The Computar lens and ULF coverage.

[sanking]

I now have had the opportunity to measure coverage of three different Computar lenses, 210mm, 240mm and 300mm. All give coverage of close to 95 degrees. Specific coverage in mm is as follows. The measurements were made on the ground glass of my 7X17 and 12X20 cameras with the lenses focused at 50 feet and could be off by a few mm.

210mm Computar, 456mm

240mm Computar, 523mm

300mm Computar, 655mm

Though not tested the 270mm Computar should cover about 590mm.

By contrast I have never seen or heard of a Kowa Graphic lens that will cover much more than 80 degrees. From this I must conclude that these are not the same lenses at all, or if they are the glass of the Kowas is installed in such as way that results in mechanical vignetting. I have never had an opportunity to examine a Kyvytar so I can not say how they compare to the Computar.

To figure out which Computar you would need for a specific ULF format note the following coverage requirements below. This is for the actual image of the negative, slightly smaller th an the theoretical diagonal of these formats.

11X14 450mm

7X17 460mm

8X20 540mm

12X20 585mm

So, we find that the 210mm Computar covers 11X14 with just a tad to spare and just misses the corners on 7X17 by a few mm. The 240mm Computar covers 7X17 with movement, and the 300mm Computar covers 12X20 with almost three inches of movement. and in theory the 270mm Computar should cover 8X20 with movements and just hit the corners oin 12X20.

I offer this information in an effort to clear up some of the confusion about Computar/Kowa/Kyvytar lenses and in the hope that more ULF workers will discover and use these wonderful lenses. In many ways they are truly unique and provide coverage for the size that simply is not available in any other design, regardless of price. They share some characteristics with Dagors but the circle of illumination of the Computar is not only about 10 degrees larger than the Dagor, but performance at the edge of the field is much superior.

Now I have got to go find a 270mm Computar!! And if anyone has specific design information about these lenses I would be very appreciative if you would provide me with the source.

[tim atherton]

very useful stuff Sandy.

What aperture was that all done at? And were they barrel mount or shutter? (with the Kowa 210mm there is some mechanical vignetting when the lens is barrel mounted)

thanks

[Ernest Purdum]

Thank you for your worthwhile work. I hope more people will follow your good example.

[Roger Hein]

Sandy, FWIW I had an Apo Kyvitar 240mm for a short time and was able to use full rise on 8x16 (IC ~450mm) without any problem. That particular lens was also a 'convertible' (converted to something like 420mm).

[sanking]

Tim,

I used f/22 in looking at the image on the ground glass. However, I feel reasonably sure that you would have to stop down to f/32 or f/45 for optimum performance across a field this large. In any event over 95% of the negatives I make with 7X17 and 12X20 format are made at F/45 or f/64. Of course, as you know stopping down a lens improves performance at the edges but doe not increase the actual size of the circle of illumination.

The 240mm and 300mm lenses were checked in a Copal #3 S shutter. I looked at the image of the 210mm lens in its barrel mount.

Which brings me to a question. With the 240mm lenses I have something that appears to be a spacer of about 0.060" thickness, but I don 't have one for the 210mm lens. I notice on the 300mm lens, which I purchased already mounted in a Copal 3 S shutter, that the spacer is installed between the shutter and the rear element and obviously increases separation between the front and rear elements. Does anyone know the purpose of this spacer? Is it to correct for infinity focus when using the lens in a shutter? Or is it to correct for a discrepancy between spacing in the barrel and shutter? I am speculating that without the spacer the coverage of the 210mm would be slightly greater but am concerned that performance may not be as good.

[sanking]

"Sandy, FWIW I had an Apo Kyvitar 240mm for a short time and was able to use full rise on 8x16 (IC ~450mm) without any problem. That particular lens was also a 'convertible' (converted to something like 420mm)."

Roger,

That would certainly be similar in coverage to the Computar. In the back of my mind I remember someone else mentioning that they had a 240mm Kyvitar that covered 7X17, and I don't believe it was you, so it seems that the Kyvitars may cover like the Computars. But do all of them? And given the questionable lineage of these lenses it might also be presumptious to conclude that all Computars have 95 degree coverage. But the three I have tested all do, and to be a bit more specific, all three have serial numbers in the 500xxx.

[tim atherton]

Again, another bit I copied from somehwere. How accurate it is - I don't know:

"Many years ago, Burleigh-Brooks introduced a line of lenses under the name of Computar; the Kowa Lens Company of Japan made them. These lenses were a remarkable value as they were a wide-angle plasmat, excellent quality and quite inexpensive. After Burleigh Brooks folded, the lenses were briefly carried by Kyvyx and were called Kyvytar and then independently offered by Kowa a Kowa Graphic lenses, in both shutter and barrel."

Presumably it would seem some changes in contruction/design occurred over that period?

[Michael Jones]

Sandy:

The spacer is to adjust (optimize) the focus at a specific magnification. If you could find the View Camera article on the Doktor (sp?) Jena lenses of a few years ago, it explained how these process lenses are optimized for a specific focussing range and magnification and the cells are spaced accordingly with the "trimming" ring. For "landscape" work (focussing at infinity), I believe you remove the ring. Thanks for the comparison of the Computars.

Mike

[Kerry L. Thalmann]

Sandy,
Good stuff! Thanks for sharing the info. I'm currently looking for a compact lens in the 150mm - 165mm range for use on the 4x10 format. I just got a 159mm f12.5 Wollensak Extreme Wide Angle Raptar (a later coated sample in a Rapax shutter) and also have a 150mm f9 Graphic-Kowa in a barrel I plan to slip into a Copal No. 1 shutter. I haven't had a chance to shoot any tests with them yet. Obviously, the Wollensak will cover with room to spare, but I'm curious to see how the performance compares to my other newer multicoated lenses.

Based on your results, and other posts I've read, it looks like the Computars cover about 95 degrees and the Graphic-Kowas about 85 degrees. If that's the case, the 150mm Graphic Kowa will hit the corners of 4x10, but leave very little left for movements. So, does anyone know if they made the f9 Computar in the 150mm focal length. I seem to see a lot of 150mm Graphic-Kowas, but don't recall seeing any f9 Computars shorter than 210mm.

Other "similar" lenses that would be interesting to test would be the f9 Fujinon A series and f9 Germinar-W series. The Fujinons are rated to cover 70 degrees, but like many of these lenses throw a significantly larger circle of illumination. Problem is the corners get real soft at the extremes. For example, a 180mm f9 Fujinon A just BARELY misses hitting the corners of 8x10 (a VERY small amount of vignetting in the extreme corners), but the image (at f22) becomes too soft to be usable for anything larger than 5x7 with moderte movements. Perhaps it would sharpen up more (and actually hit the corners of 8x10) if I tried it at f45 or f64. Has anybody tried really pushing the coverage of the A series Fujinons? I use the 180 and 240 regularly on 4x5 and 5x7, but don't usually shoot anything larger. So, I haven't done any conclusive tests on large formats.

The Germinar-W series is very interesting. It is a very compact (similar to Fujinon A and G Claron) f9 plasmat type lens. Don't confuse it with the much more common, larger, single coated APO Germinar-W series. The (plain) Germinar-W was the last series introduced by Docter Optic before they went out of business. Unlike the earlier APO Germinars and APO Germinar W models, it is also beautifully multicoated. The shorter focal lengths screw directly into standard Copal/Compur shutters. I have a little 150mm f9 Germinar-W for backpacking with the 4x5. I mounted it in a newer style Compur 0 and it weighs only 130g. I know it will cover 5x7, and probably 4x10 (the circl;e of illumination is large enough, not sure on the corner sharpness). If you can find any of the longer (240mm, 300mm, 360mm) Germinar-W lenses (good luck!), they would probably make excellent lenses for ULF use. If you ever do get any, please let us know how they compare to your Computars.

Kerry

[sanking]

Tim,

Thanks for that information. Any idea about time line on these events?

I had pretty much concluded that the Computar had to be of Dagor or Plasmat (which is kind of a split Dagor) design, but it nice to have confirmation. That would mean they are of symmetrical design and could be used as convertibles, using the rear element alone, at about 1.75X the focal length of the combined elements. Be interesting to see how the individual cell will perform by itself.

But I am curious why this particular lens, of all the Plasmat type processes lenses made, had some wider coverage than the others?

[tim atherton]

Okay - here's the other bit I snipped (first post didn't seem to make it) - again, I'm not sure if this was actually talking about the Computars or Kowas (though apparently both were made by Kowa?)

"Some times the barrel lens will come with thin spacers. The trick is this, for center image use, the more spacers between the rear cell and the shutter the better. For the corners of the image, no spacer is best. This is why, in a shutter mount, we often see one spacer as the best overall compromise."

[tim atherton]

Kerry, I've read the Kowa 150mm is supposed to cover about 290mm? (what's the circle for 4x10?)

Also, the APO-KYVYTAR's where apparently made in 150mm - don't think I've seen a reference to a Computar 150mm.

BTW Sandy, I've bid on a couple of Computar 210's on ebay in the last six months (more out of curiosity to compare with the Kowa). I didn't win, but neither went for more than $420.00... Also, one was obviously an original factory shutter mount with the dual/convertable aperture scale.

[tim atherton]

"The Germinar-W series is very interesting"

Kerry, did they ever make a 190mm f9?

[tim atherton]

Here you go Sandy (I've got these scattered through different emails that I use to "clip" notes into...) - again, I can't remeber where I clipped it from - might have baan an ebay sale....

"The following is from the beat up information sheet, (a letter) which was packaged with my 305/537 APO-Kyvytar and in the box with the Korona.

It is not dated.

"APO-KYVYTAR lenses are made by the same people in Japan that made the convertibles under the "Computar" trademark which I used to own and which I sold to Chugai International Corporation who use the trademark for their video lenses, enlarging lenses, and the large format taking lenses (Computar Symmetrigons).

The APO-KYVYTARs are the same formula as the former Computar convertibles except that the APO-KYVYTARs are one stop faster, i.e., 6.8 instead of 9.0

The APO-KYVYTARs convert to a focal length just a little less than double the nominal focal length simply by un-screwing the front element and using the rear element.

The APO-KYVYTARs convert in focal length as follows:

>From 150mm to 264mm 210 370 240 422 270 475 305 537 360 633 480 845

The diaphragm scale is a double scale. The second scale is for use with the single rear element. The rear element alone is slightly softer and therefore good for portraits where it is desirable to shoot farther from the subject and soften the texture of the subjects faces.

Both elements together give you the sharpest picture, and flattest field, and the best color that money can buy!"

It is signed by J. Callahan, President, KYVYX Corporation, South Hackensack, NJ."

I've tried my 210 as a 370mm - it' actually pretty nice. But I have only really used it for close-ups of flowers, so the background i all out of fiocus anyway - so not really a scientific test. That said, as a 210mm lens, it's a sharp snappy little bugger

BTW - the Kowa's also become 6.8 once you put them in a shutter (I think Jim Galli forked out for a WA Kowa 6.8 only to find it was exactly the same as his barrel f9 he had, only difference was it was already mounted in a shutter...?)

[tim atherton]

lets try this:

150mm to 264mm

210 370

240 422

270 475

305 537

360 633

480 845

[sanking]

Tim, Kerry

Wow, thanks for all of the additional information. This has turned into one of those ask and yee shall receive threads.

Kerry, do you have a list of the focal length in which the Germinar-W was made?

Tim, the information about the spacers is very useful. This is just a rough estimate but I am guessing that by not using the spacers when I put the 210 Computar in a shutter the elements will be about 0.12" closer, which should result in an increase in coverage of some 10-15mm. If that is indeed the case it will hit all of the corners on 7X17, with just a tad to spare.

[Kerry L. Thalmann]

Kerry, I've read the Kowa 150mm is supposed to cover about 290mm? (what's the circle for 4x10?)

Allowing for film holder margins, about 266mm.

The 290mm figure, as well as 460mm for the 210mm focal length are from an article Gordon Hutchings did many years ago for View Camera. I believe that article is also the source of your quote above about Burleigh-Brooks and the lineage of the Computar/Kowa/Kyvytar lenses.

What's confusing about the numbers is the inconsistancy of the stated coverage. A 460mm image circle from a 210mm lens equates to 95 degrees of coverage (in line with Sandy's data for his Computars). With 95 degrees of coverage, the 150mm focal length should have an image circle of about 327mm, not 290mm. So, why does the 150mm cover so much less (if in fact it does). As both lenses are designed to fit in a Copal No. 1 shutter and both take the same size filters, I would not suspect mechanical vignetting to limit the 150mm coverage so significantly. The other possibility is the 290mm figure was for a 150mm Graphic-Kowa, and the 460mm spec was for a Computar. I have no idea of this is true, but it falls in line with Sandy's conclusion that these are indeed two different designs with the Computar having the greater coverage.

Kerry

[Kerry L. Thalmann]

Kerry, did they ever make a 190mm f9?

No, they jumped right from 150mm to 210mm.

Kerry

[sanking]

Kerry,

One more comment about the Graphic Kowas. The experience of others may be different but mine is that they do not quite hit 80 degrees of coverage. I tried several different 360mm specimens on 12X20 and they all missed the corners. My calculations are that a 360mm lens would cover 12X20 if it had a full 79 degrees of coverage so the fact that the Kowas did not puts the ones I sampled below that figure.

But maybe the ones of shorter focal length do go 80 degrees or more. It is not uncommon for lens manufacturers to reduce coverage on the longer focal length lenses. I believe this was true of the Fujinon-W, for example. I have a 180mm f/5.6 Fujinon-W that covers more than 80 degrees, but a 360mm F/6.3 I owned missed the corners on 12X20, which puts it below 79 degrees.

[sanking]

"The 290mm figure, as well as 460mm for the 210mm focal length are from an article Gordon Hutchings did many years ago for View Camera. I believe that article is also the source of your quote above about Burleigh-Brooks and the lineage of the Computar/Kowa/Kyvytar lenses."

Anyone have the year and month of this article?

[Kerry L. Thalmann]

Kerry, do you have a list of the focal length in which the Germinar-W was made?

Sandy,

Off the top of my head...

150mm, 210mm, 240mm, 305mm and 360mm. I believe all but the 360mm are direct fit in standard Copal shutters (No. 0 for the 150mm, No. 1 for the 210mm, 240mm and 305mm). I believe the 360mm requires an adapter for one of the cells to fit in a Copal No. 3 shutter.

My sources for this information are Arne Croell and Joerg Krusche. Arne had a real good two-part article on the Zeiss VEB and Docter Optic lenses in View Camera last year. I don't remember the exact issues off the top of my head (sometime in the second half of last year), but part 2 of the article covered the Docter Optic lenses, including the Germinar-W lenses.

Kerry

[Kerry L. Thalmann]

Anyone have the year and month of this article?

Sandy,

I don't have my back issues with me, but I'll check tonight.

In the meantime, if you have your back issues handy...

I believe it was in the 1992 - 1994 time frame, possibly Nov/Dec 1993.

Kerry

[sanking]

Kerry,

My god, you were right. The article is in the Nov/Dec 1993 issue.

You must have an incredible memory. I would not have remembered the information if it had been in the Nov/Dec 2003 number.

Thanks.

[Kerry L. Thalmann]

My god, you were right. The article is in the Nov/Dec 1993 issue.

You must have an incredible memory.

My siblings constantly tease me about being able to remember events that happened before I was born.

While I do have a good memory, especially for numbers (I still remember the license plate numbers for cars I drove back in the 1980s, phone numbers of my high school friends from the 1970s and birthdays of kids I went to elementary school with back in the 1960s - scary), in this case I must confess I cheated a bit. I remembered the article had the phrase "Semi-Wide Lenses" in the title. So, I went to the View Camera web site, opened their back issues index and did a search on that phrase.

BTW, a while back they converted the back issue index to PDF format, which is searchable. I have a complete collection of the magazine going all the way back to Volume 1 Issue 1. When I want to find a specific article or subject, I find searching the PDF a lot easier than wading through 16 years of back issues.

Kerry

[Steve Hamley]

Sandy,

I believe the 360 Kowa is not a plasmat. The reflection pattern I get from the front and rear cells of my 360 Kowa Graphic are two inverted very close images, and two wider spaced upright images. I get exactly the same pattern from my 19" Artar.

In contrast, my 240 Computar has exactly the same reflection pattern as my 270 G-Claron: 4 evenly spaced upright images. I do get a ghost on the G-Claron that I can't see in the Computar, but the Computar's area is much smaller and maybe I'm just not seeing the ghost.

Anyway, I think the probability is that the 360 Kowa is a dialyte.

Steve

[sanking]

"Anyway, I think the probability is that the 360 Kowa is a dialyte."

Steve,

I wonder if the entire Kowa line was not changed at some point to the dialyte design?

[tim atherton]

"I wonder if the entire Kowa line was not changed at some point to the dialyte design?"

I'm not sure. My experience with the Kowa 210mm is about the same as Jim Galli's with the same lens I think.

I get at least 380+ mm of coverage/usable image circle @f22 with mine - not as much as the 460mm listed for the Computar 210, but much more than I got with a G-Claron 210mm - which I found gave about to be about 325/335mm at most @f22 (and starting to go slightly soft at that)

(example - today I was out using the Kowa 210 on 8x10 and at one point I used at least 2 1/2" of fall (with focus over 50') and I wasn't running out of image circle @f32 - not a hint of darkening or softenss in the corners of the neg)

[tim atherton]

I meant to add... so if it was a dialyte design, I wouldn't be likely to be getting that kind of coverage with the 210mm would I?

[Steve Hamley]

Sandy,

Maybe, or maybe just the long ones? Tim posted on the other ULF thread that his Kowa 210 had coverage that would indicate it was not a dialyte.

Thanks!

Steve

[Dan Fromm]

Steve, about those reflections. Spacing doesn't matter, count by brightness does.

A plasmat should show four bright reflections and one dim one in each cell. The dim one may be very hard to see. That's four air-glass interfaces, one glass-cement-glass.

Dagor types should show two bright and two dim reflections in each cell. Again, the dim ones may be hard to see. Two air-glass interfaces, two glass-cement-glass.

Dialytes, e.g., Apo Artar, Apo Ronar, and four element double Gauss types, e.g., WF Ektar, Process Nikkor, should show four bright reflections in each cell. Four air-glass interfaces.

Tessars should show four bright reflections in the front cell; two bright, one dim in the rear cell. Reversed tessars have'em the other way 'round.

And so on.

FWIW, by this logic my 150/9 Konica Hexanon GRII and 160/5.6 Pro Raptar are plasmats and, as Tim Atherton and I have discussed, the 210/9 GRII, which has six bright reflections on each side, is 3,3 with no cemented elements.

Any coverage measurements/SWAGs for GRIIs or Pro Raptars out there?

Yours for the spread of confusion in ever widening circles,

Dan

[Colin Myers]

Hi Sandy

A small piece of additional information regarding the Computar lens in 210mm focal length, or a little something to further muddy the waters. I have a 210mm/f6.3 lens marked apo computar symmetrigon, aperture range f6.3 to f90, mounted in a contemporary Copal 1 shutter, lens # 17xxxx. Only today a friend of mine purchased a near identical 210mm computar, marked computar symmetrigon, again mounted in Copal 1 shutter , aperture range f6.3 to f64 with similar 17xxxx number. It will be interesting to see if the image circle and performance of these two lenses will be the same. Is the "apo" a selling / marketing gimmick, or what? I think the subject of these Graphic Kowa/Computar/Kyvitar lenses, their history, performance etc, would make for a fine article in View Camera by someone like Kerry Thalmann. How about it Kerry.

[Michael S. Briggs]

The f6.3 Computar Symmetrigon mentioned by Colin is a different lens from the plain Computar that most of the other posts have referred to. When people talk about the coverage of Computar lenses, they should be clear whether the lens is a Symmetrigon or not. The Symmetrigons seem to be more common on the used market. They can also be distinguised by the f6.3 max apertures.

I have a brochure on the Computar Symmetrigon. The lens is four elements in four groups. The design cross-section is _roughly_ like the famous Metrogon. Strangely, despite the name, the optical design of Symmetrigon is definitely non-symmetrical. The brochure specs the coverage as 72 degrees.

Probably the Apo Computar Symmetrigon is the same as the Computar Symmetrigon, with the "Apo" designation added for marketing reasons.

[Colin Myers]

Michael, Thanks for the clarification on the Symmetrigon name. What sort of information does your brochure include, anything on usable image circle? I would think, that as a direct function of the smaller angle of view, the image circle would also decrease and be less than the 90degree Computar lenses. On a practical note, how does one go about measuring the image circle of a lens? Colin Myers

[Ernest Purdum]

Colin, you are correct in thinking that the angle of view and the image circle size are directly related.



The usual way of measuring the image circle is to put the lens on an oversized camera, set it at infinity and preferably, take a picture, so that the circle can be directly measured off the negative or print. This is better than measuring off the groundglass because you can get a more accurate idea of how much of the circle is usable image and how much is too soft or too poorly illuminated to use. There are two major problems, though. If the lens is for an 8" X 10", you probably don't have a camera big enough to display the whole circle. If the lens is a wide angle, a camera large enough for the job may not be able to close up enough to focus the lens at infinity. If you have a camera with large shift movements, you may be able to use these to obtain your measurement. There have been special cameras made for this purpose, but they are useless for anything else.



Sometimes the image circle for process lenses is measured when focused for 1:1 magnification instead of at infinity. If so, you can convert the figure just by dividing by two.



Manufacturers are often conservative in their image circle claims. As a result, you will find users saying that their lenses exceed the published figure.

[Ernest Purdum]

I should have mentioned that most commonly image circles are measured at f22.

[Michael S. Briggs]

Trigonometry gives an equation relating angle of view theta and the diameter of the circle of coverage d (at infinity) for a lens of focal length f:

d = 2 f tan (theta / 2)

For 72 degrees stated by the manufacturer for the Computar Symmetrigon, this is d = 1.453 f. The results from this equation agree within a couple of mm with the values given in the brochure.

[Arne Croell]

Wrt to the Docter Germinar-W's, the focal lengths (150,210,240,305,360mm) and shutter sizes (150: size 0, 210-305: size 1, the front cell of the 360mm fits a size 3 shutter, but the back cell needs an adapter) Kerry quoted are all correct. Another proof of his excellent memory. All are f/9. My articles he referred to appeared in the July/August (Carl Zeiss Jena) and Sept/Oct. (Docter Optics) 2003 issues of VC. The only correction I have to make is that the Apo-Germinar W's (150, 210, 240mm, f/8, but MUCH bigger than the "plain" Germinar W's) are also multicoated, not single coated. Actually, these were even multicoated in their earlier Carl Zeiss Jena incarnation, since they are not Plasmats like the Germinar -W's, but use 8 uncemented lens elements = 16 glass-air surfaces.

[Kerry L. Thalmann]

Arne,

Thanks for the the additional info on the APO Germinar-W lenses. When looking for a compact wide angle for my 4x10, I dismissed the 150mm APO Germinar-W due to the limited coverage. You list the image circle as 370mm at 1:1 in your article, which would make it about 185mm at infinity - barely enough for 4x5 and way too small for 4x10 (or even 5x7).

The little Germinar-W seems to be a much more useful design. As you noted, it was a late introduction from Docter Optic after they acquired the former Zeiss VEB assets. As it was smaller, lighter, fit in smaller shutters and had more coverage, perhaps it was slated to replace the older APO Germinar-W line that was a carry over from the old Zeiss days. Too bad Docter went out of business so soon after the introduction of the Germinar-W line. I really think it would have been a good seller for them.

Kerry

[Kerry L. Thalmann]

OK, now I'm really starting to get confused regarding the whole Computar - Graphic-Kowa issue. I briefly checked the reflections in some of my lenses over the weekend and could not make any definitive conclusions. Note, when I'm talking about the reflections I observed, I am referring to the single front cell only. I believe all the lenses I checked are symmetrical. So, they should show similar reflections in the rear cells as well.

With my 180mm and 240mm Fujinon A and my 210mm G Claron, I could definitely see the faint fifth reflection from the cemented surface Dan mentions above. So, four bright reflections and one faint, just like you'd expect from a plasmat design.

With my 9½" Red Dot Artar, I could see the expected four bright reflections. However, I noted that two of the reflections were very closely spaced, practically on top of each other. From some angles, it looked like only three reflections total. Turning the lens slightly would reveal that it really was four reflections.

Confusion set in when I got to the 150s. As hard as I tried, I could NOT get a fifth reflection on my 150mm f9 Graphic-Kowa. It had four very distinct, separate reflections (without any overlapping like the Artar). So, to me, it looked like this lens consists of four elements in four groups. The 150mm G Claron was an enigma. No matter how hard I tried, I could only see TWO bright reflections and one dim, when I should see four bright and one dim. I suspect this was due to the very small size of this lens. The two groups of two probably had enough overlap that it just looked like two reflections instead of the expected four. With the 150mm Germinar-W, I could easily see the four bright reflections, but no matter how hard I tried, I could not see the dim reflection. Perhaps the front element was just too small to show all the rfelections simultaneously.

So, back to the Computars and Kowa-Graphics... Does anybody have ANY original literature on these lenses? Based on the discussion and Sandy's results, it appears that they are not, (at least in all cases) identical designs. It also appears that the possibility exists that there might be two different designs for the Graphic-Kowa series. I was all set to hypothesize that perhaps the 150mm and 210mm Graphic-Kowas were f9 6/4 process plasmats and the longer focal lengths were 4/4 dialytes. That would help explain the conflicting reports of covrage regarding the various focal lengths. Then my 150mm Graphic-Kowa threw me for a loop with the absence of the faint fifth reflection. It sure would be nice to get some definitive info straight from the source.

So, what about the Computars? I don't have any currently to check reflections. Sandy could you check yours and let us know what you see? Perhaps they might all, including the longer focal lengths, be 6/4 process plasmats, which traditionally have more coverage than 4/4 dialyte designs. However, even that doesn't account for the ~95 degree coverage Sandy has measured. I have a theory to toss out here. It's just a hunch, based more on intuition than data. Another popular 4/4 design is the wide field Gauss. The most famous example is the Wide Field Ektar series with about 85 degrees of coverage. However, other 4/4 wide field Gauss designs have claimed coverage up to 100 degrees (Cooke Series VIIb). Could, perhaps, these Computars (and maybe some of the Graphic-Kowas) be modfified wide field Gauss designs? That might also explain why the reflections in my 150mm Graphic-Kowa and 9½" Red Dot Artar, while identical in number, are grouped differently (four distinct separate non-overlapping reflections vs. two groups plus two with significant overlap). Unfortunately, I don't currently have a Wide Field Ektar in my possession to compare reflections to my 150mm Graphic Kowa. FWIW, the elements in my Graphic-Kowa are significantly larger than my 150mm G Claron and 150mm Germinar-W - which in addition to the difference in reflections, leads me to believe they are of dissimilar design.

In lieu of original literature, I'd appreciate it if others would check their lenses for reflections and compare their Computars and Graphic-Kowas to lenses of known contruction and report their findings here. Perhaps with our collective inventory of lenses we can come up with an answer to this mystery.

Thanks, Kerry

[Dan Fromm]

Kerry, re y'r wide angle Gauss thought, I'm sure you know that f/10 Process Nikkors, e.g., the 260/10 that's growing dust in one of my drawers, are 2,2 wide angle Gausses. It seems to me that there's considerable confusion between dialyte and w/a Gauss. There's a common, unfortunately mistaken, assumption that all 2, 2 lenses are dialytes.

Both types are symmetrical. In the dialyte, the front cell's elements are () )(, in the w/a Gauss they are (( ((.

Dialytes can have slightly wider coverage than most of us think. Per the Vade Mecum, TTH recommended using f/4.5 Series IIB Aviars as normal lenses, i.e., using the 150/4.5 on 4x5.

Cheers,

Dan

[Arne Croell]

Due to the difference in construction as described by Dan, the reflections of the dialytes and the Gaus WA design, although the same in number, behave very differently. In the dialyte, 2 surfaces are convex towards the viewer, and 2 are concave. In the Gauss, all are convex towards the viewer. So if one tilts the lens or moves the light source, all reflections move in the same direction in the case of the Gauss (although at different relative speeds), whereas in the case of the classic* dialyte 2 reflections move in one direction, and 2 in the opposite one.

* I know of a russian dialyte process lens having a positive and a negative meniscus instead of a bikonvex and a biconcave lens as in the classic dialyte, but that is an unusual example.

[Jim Galli]

I'll add a little to the confusion. After a couple of disappontments I've decided it's too expensive to buy these and not have the additional coverage. For instance I've bought a 270mm and 305mm Graphic Kowa to mount in Copal 3S only to discover as has Sandy that they definitely are not the same animal as the earlier branded lenses. The 270 would clip the corners on 11X14. Who needs a relatively heavy 270mm in an expensive heavy shutter that won't cover 11X14? No one. Here is what I surmise happened over time. I had (still have the front group) a 210 Graphic Kowa that was so stuck in it's mount that I had to chuck it into a lathe jaw to break it loose. I got three chips in the outer glass as a result of the pressures. So I took it apart. It is 3-3 construction each cell. 3 glasses / all air spaced. That would account for a reduction in coverage whenever Kowa went to that design from the wide field plasmat of the earlier Computar. But wait. There are Kowa's and there are kowa's and no physical way to tell them apart. I have another 240mm Graphic Kowa that I was going to list on Ebay. So I took it upstairs just last night and put it on the 8X20 and made a photograph on film. At f90 it actually covered 8X20. Un-useable but covered. Certainly useable on 11X14 and 7X17 I should think. Having just finally read this thread this AM I don't have my collection here in front of me to check reflections with a pen light source but will do so tonight.

[Jim Galli]

Checked reflections in 4 qualifying lenses. 240 f9 Graphic Kowa (covers 820) 210 Graphic Kowa f9, 210 Kyvytar f6.8 in factory mount Copal 1, and 210 f9 (identical to the Kyvytar) in factory Copal 1. All reflected identical. Blew up my theory of a change later on by Kowa. They appear to have 4 surfaces reflecting just like Kerry says. All 4 the same. But the broken 210 Kowa is the one I've taken apart and there are 3 air spaced glass elements in 3 distinct groups with spacers between each. It's a mystery. With the 3 together I see 4 reflections. OK 5 at best if you count the giant one from the source that takes up the whole top. Don't know if that helps or just adds to the confusion. It is NOT a wide field gauss. Air spaced plasmat?

[Arne Croell]

Jim, you have to count every reflection including the big one. It could be that one is masked by two elements being close together and having nearly the same curvature - an example for that is the front group of the old Voigtländer Telomar; only 3 strong reflections can be seen, although there are 2 elements with a thin airspace. The reflections of cemented interfaces can be hard to see if the refractive indices of the glass are close to each other. Also expectations can play a role in perception - I believed for a while that all of Meopta's older enlarging lenses where Tessar types and when a Meopar came my way I checked the reflections and found 4 in the front cell and 2+1 in the back, as I was expecting. Later I learned they are actually Heliar types and rechecked, and sure enough there was the additional faint reflection from a cemented interface in the front group which I had initially overlooked, because I only checked for Tessar vs. Triplet or Plasmat. Btw, some of the Konica GRII process lenses are also 6 elements airspaced.

Kerry, wrt the Apo-Germinar W 150mm, it sure does not cover 4x10. The 185/370mm is Docters official number; now the MTF curve at that angular coverage is still up high so more coverage seems possible, but I cannot get more than 25mm of rise with 4x5 in portrait orientation out of the shuttered version; after that the mount vignettes for good. That should be equal to about 200mm image circle, not so far from the official value. The interesting trend with the Apo-Germinar W's is that the coverage goes up with focal length, which is opposite to other lenses, but even with the 240mm (72° officially) it is a far cry from the 95° we're talking about here. I haven't checked the coverage (officially 70°) for the Germinar W's yet.

Strange occurence with your 150mm G-Claron - I could see all 4 main reflections and the dim one in mine. But the reflection counting is a finicky business and depends a lot on the lighting used. It is advisable to have only 1 light source, and the distances from the lens to the light source as well as to the eye are important. Some reflections can only be found with the light source (flashlight) close to the lens. I have found that the white LED's used in the new light weight flashlights for backpacking (Petzl and other manufacturers) make a great source for this purpose. I usually have the lens steady on the table and move the flashlight around as well as up and down (including close to the lens) to do this.

[Arne Croell]

I just popped both my 150mm G-Claron and the 150mm Germinar W on my 4x5 and checked visually their circle of illumination. Both are quite similar and allow about 55mm of rise with 4x5 in portrait orientation before the mount vignettes; this is equivalent to a circle of about 250mm diameter, or 80 degrees coverage for the circle of illumination. And the reflection of the cemented interface on the Germinar W can be seen, but is one of those where it just has to have the exact angle between illumination and viewer - when visible, it covers the entire lens area as an out of focus image. This is usually the case when the surface is very shallow concave towards the viewer, close to flat.

[sanking]

"So, what about the Computars? I don't have any currently to check reflections. Sandy could you check yours and let us know what you see? Perhaps they might all, including the longer focal lengths, be 6/4 process plasmats, which traditionally have more coverage than 4/4 dialyte designs. However, even that doesn't account for the ~95 degree coverage Sandy has measured. I have a theory to toss out here. It's just a hunch, based more on intuition than data. Another popular 4/4 design is the wide field Gauss. The most famous example is the Wide Field Ektar series with about 85 degrees of coverage. However, other 4/4 wide field Gauss designs have claimed coverage up to 100 degrees (Cooke Series VIIb). Could, perhaps, these Computars (and maybe some of the Graphic-Kowas) be modfified wide field Gauss designs? "

Kerry,

This is an interesting idea. Unfortunately I will be on the road for the next couple of weeks and don't be able to have a look at the Computars until then. But I will do so as soon as I return home.

[Annie M.]

Reflections in the 240 9.0 Computar

Not exactly sure about how to read the reflections but here are my observations. I removed the front lens cell and with a point light source there appear 5 reflections in a line down an axis into the lens (hope this makes sense)..... 2 smallest front and centre... then one on its own also small... Then another on it's own but a bit larger....then at the very back the largest one, not bright but 'ghostly' and about 3x the diameter of the one proceeding it...... The rear cell shows the same.....I have no idea if this tells you anything but thought I would give it a shot.

Cheers Annie

[Jim Galli]

Sandy, Sorry, one of the 4 above is Computar 210 f9. Everything about it is identical to the Kyvytar and both Graphic Kowa's. All reflect the same. On my way upstairs to do 2 shots on the 8X20 with both Computar and Kyvytar 210's.

[Jim Galli]

OK. Drum roll please. Oops nobody's here anymore. Oh well. Made my 2 8X20 photos. On film. 210 f6.8 Kyvytar in mid '80's 2nd type Copal 1 came in at a solid 385mm and useable right to the edge pretty much. The Computar 210 f9 is in the early 1st type Copal 1. 420mm with about 390 useable. What you're seeing out past the 420 is a halo. Very weird. Like the image stops at 420, then there's 7mm blank un-exposed, then theres this halo that goes out to maybe 450 but no image. Both were at f64 focused at infinity. Both are dandy 8X10 lenses. Neither is ULF.

[Harold Clark]

I thought I would weigh in on the Kowa debate. I picked up 150 & 210mm Kowa f9 lenses in barrel very cheaply, and screwed them into #1 shutters. Here are my abservations: 210mm- on my 8x10 Deardorff using maximum rise(66mm) I photographed my favorite test subject, the back of my house from a distance of about 30 ft. @f45. The 210 covered and was considerable sharper than a 210 g claron I tested at the same time. The 150 just clipped the corners of the negative. I also tested the 150 on my 5x7 sinar with 45mm of rise, shooting a stand of cherry trees at the edge of my yard. The negative shot with the spacer was considerable sharper in the corners than the one shot without, although I can't remember now whether the cell spacing in shutter was the same as the barrel. The Kowas are exceptionally sharp lenses. I enlarged the central portion of a 4x5 negative 10 times (210mm f22) and it looked like a 35mm print.

[John Z.]

A question for Jim Galli and the others, at risk of reviving a long old thread; I have moved up to 11x14, and am studying my options for a few wide angle lenses--meaning perhaps a 300mm and a 240mm lens. Since you have experience with so many lenses, would I be better off with a Kowa combination of the 240, 300 and possibly adding the 360 lenses, which are 1) very sharp, 2) very compact, and 3) not too expensive, or should I look for a few Dagors in the 240 and 300mm focal lengths? My question comes down to asking if you think the Kowa lenses are comparable to Dagors in image quality for wide angle photos. Thanks for your input.

[Kerry L. Thalmann]

More Reflection Confusion

OK, I did some more checking of reflections on various lenses. This time I used more controlled conditions - a single white LED in a dark room. I removed my glasses to eliminate any reflections off the eyeglass lenses. I also observed the reflections with one eye closed to eliminate any double vision caused by crossing of the eyes when tying to focus up close. By moving the LED light source around, I made the following observations:

150mm f9 Germinar-W - OK, now I see the faint fifth reflection (four bright, one dim - as expected for a plasmat). All five reflections move in the same direction when the light source is moved. BTW, the multicoating on this little lens is just beautiful - every reflection is a very distinctly different color.

150mm f6.8 APO Kyvytar (no serial number) - Again, classic plasmat five reflections per half (4 bright, one dim), all move in the same direction when the light source is moved. Single coated (all reflections white to light magenta)

150mm f9 Computar (serial number 500xxx) - Ditto

150mm f9 Graphic Kowa (serial number 153xxx) - Ditto, except the coatings on this one are definitely more "brilliant" and colorful. Two of the bright reflections (the first and last) are bright lavendar (more purple and more brillant than the pale magenta reflections common to single coated lenses from the 1970s). This, combined with the other two reflections almost lead me to believe this lens is multicoated - one is bright yellow (the second bright reflection) and the other (third bright reflection) is a brilliantly bright light blue (cyan). These improved coatings would seem to indicate a later manufacturing date than my APO Kyvytar or Computar. So, is it possible late Graphic Kowa lenses are multicoated? Anybody else have one with brilliant, multi-colored reflections? (Note: someone once told me in an email that his Graphic-Kowa was muticoated. I was skeptical and told him all the ones I'd seen were single coated - which was true at the time. Now I'm wondering if he was right and I was wrong).

180mm f9 Fujinon A - Five reflections per half (4 bright, 1 dim). The one dim reflection moves in the opposite direction as the four bright ones when the light source is moved. Multicoated.

210mm f9 G Claron - Ditto, except single coated.

210mm f9 Graphic Kowa (serial number 226xxx) - Here's where it gets interesting - and this may also explain the greater angle of coverage quotes in the Hutching’s article for the 210mm (~95 degrees = 460mm IC) vs. 150mm (~88 degrees = 290mm IC). In the Hutching’s article, he doesn't differentiate between the three "brands" (Computar, Kyvytar or Graphic Kowa). So, it's hard to determine where his numbers come from and which lenses they apply to. In any case, this particular 210mm f9 Graphic Kowa is DEFINITELY of different construction than my 150mm f9 Graphic Kowa (or any of the other plasmats mentioned in this post). This lens definitely has SIX bright reflections per half. This would indicate an air spaced design (no cemented elements) of three elements per half (six elements total in six groups or 6/6 in the common notation). This appears to be similar construction to the 210mm f9 Konica GRII mentioned by Dan above, and also matches Jim's observation on the damaged 210mm Graphic Kowa he disassembled. The reflections on this lens are the standard white/straw and magenta of a single coated lens – indicating an earlier manufacturing date than my 150mm Graphic Kowa. Also, the largest two reflection overlap significantly and move in unison. However, they are definitely two separate reflection. This is definitely a single coated lens of 6/6 construction.

So, an interesting new data point. However, keep in mind that I have exactly ONE sample of each lens mentioned - and NO 210mm f6.8 APO Kyvytar or 210mm f9 Computar to compare.

My next experiment will be to compare coverage of several of the 150mm lenses (G Claron, Germinar-W, APO Kyvytar, Computar, Graphic Kowa, APO-Sironar-W and any others I can get my hands on) by shooting them on 8x10 film. My main interest is to compare the coverage and sharpness of these 150s to pick the best one for 4x10 shooting. The results will probably also be of interest to 5x7 shooters, but none are likely to have enough coverage to hit the corners of 8x10.

In an ideal world, I'd like to repeat the experiment with the same lens types in the 210mm focal length shot on 11x14, but I don't have nearly the variety of lenses in the 210mm focal length (right now I have only a G Claron and the Graphic Kowa). Finding a 210mm that covers 4x10 is pretty easy (just about any plasmat will do). So, I haven't been trying to acquire a vast assortment of compact 210mm lenses. Nor do I have an 11x14 camera (although the effect could probably be simulated using front rise and shift on the 8x10). I'm sure a lot of 8x10 users would be interested in the results of such a test. I just don't have the lenses to conduct the experiment. Anybody else? Jim? Sandy? If nobody has a big assortment of compact 210s, perhaps several of us could bring our lenses to the large format conference in May and conduct the experiment there. I’d certainly be willing to bring my 210mm G Claron and 210mm Graphic Kowa.

Note: I have mounted my 150mm and 210mm Graphic Kowas in Copal No. 1 Press shutters, adapted them to take 52mm filters and have done a little shooting on 4x10 Velvia recently. I haven't really pushed the coverage, but they both easily cover 4x10 with no vignetting. Also, I was pleased that the fall-off with the 150, while detectable, isn't as offensive as I'd anticipated. If you have an even-toned blue sky, you may want to use a center filter, but in many cases you won't find one necessary. I'm thrilled that these lenses cover 4x10, especially the 150mm. I really like this focal length on 4x10, and was worried I'd need to go with some huge, expensive Nikkor SW, Super Symmar XL or Grandagon-N to get something in the 150mm range that covered 4x10. In a No. 1 Copal Press shutter, the 150mm Graphic Kowa only weighs about 180g - the 210mm, about 205g. Not bad for lenses with this much coverage.

Kerry

[tim atherton]

Kerry

My 210mm f9 Graphic Kowa is serial number 231xxx and gives the same set of reflections you list above.

Now, ahve you tried mixing and matching the 150mm and 210mm elements to see if you really can get some kind of usable 165mm-ish lens that covers at least 8x10? :-)

[Kerry L. Thalmann]

Now, ahve you tried mixing and matching the 150mm and 210mm elements to see if you really can get some kind of usable 165mm-ish lens that covers at least 8x10? :-)

Nope, not yet. I'll give it a try when I do my 150mm shoot out (150mm G Claron, 150mm Germinar-W, 150mm APO Kyvytar, 150mm Computar, 150mm Graphic Kowa, 150mm APO-Sironar-W and maybe 150mm Super Symmar HM if I can get my hands on one).

I'm still a bit baffled by the divergent coverage claims of the Computars vs. Graphic-Kowas. I don't dispute the claims, but I would like to understand exactly how the coverage varies and why. The only Computar I have is the 150mm and it looks idendentical (other than the coatings) to my 150mm Graphic Kowa. I'll know more once I finish my shoot-out. If anyone has a 210mm Computar and access to an 11x14 camera, I'll gladly bring my 210mm Graphic Kowa (and G Claron) to the LF Conference in Springfield so we can do a 210mm shoot-out.

Jim already did something similar with his two lenses, but I'm wondering if there is more than one version of the Computar lenses. Maybe we can get multiple samples for the shoot out. Perhaps one that is capable of covering 11x14, plus a one or two that don't. If we get enough samples, maybe we can correlate the coverage to the serial numbers.

Kerry

[Jim Galli]

Hi again all. Don't expect to make it to the LF conference but would gladly forward my lenses to Kerry's care for testing. It would be nice to get some reliable data points. A poster above asked about image quality of Computar vs Dagor. Nolo Contesto! Computar wins hands down by a wide margin. I have some other interesting 210's in the collection not the least of which is a JML. Interesting lens and breathtaking quality but I think the possibility of a modern shutter is likely the biggest driver in all these lenses. I'd love to see some data points on my "dagor type" 210 G-Claron's while we're at it. Had that one on the camera yesterday.

[Ernest Purdum]

Jim,

I'm not sure what "data points" you are looking for, but if you want Schneider's ratings of the earlier (Dagor type) G-Clarons, here they are. (Infinity at f9 and f22.)

150 166.1 192.2

210 224.7 299

240 258.1 320.7

270 289 359

305 332.1 412.5

355 385.2 478.5

Schneider gave the angle of view at full aperture as 57 degrees, the increase at f22 as 64 degrees for the 150mm and 68 degrees for the others. These figures are a little greater than those for the later (airspaced) g-Clarons. Coverage at 1:1 would, of course, be twice that of the diameters shown.

[Jim Galli]

Ernest, I have to assume Schneiders conservative data is for the original intent which is near perfect mtf across a flat field for reproduction. Our uses for general photography can widen out quite a bit as we can generally tolerate quite a bit more mtf fall off for enlarger use and more still for contact printing. I have a single 7X17 test image with the 240 for instance where illumination very nearly covers the sheet, (460mm) and acceptable definition for a contact print easily reaches out to 410-420mm. A long way from Schneider's figures. I suppose different photographers will have different tolerance levels. I find the 210 dagor type G-Claron useable for my purposes out to 370mm and the 240 out to 420. I've yet to locate a decent early example of the 270mm. I have a 150 but haven't had time to play with it yet.

[Harold Clark]

I have the 150mm & 210mm Kowa graphic lenses. Both came in barrels and I have mounted them in copal 1 shutters. They are definitely of different construction though. I disassembled them to clean a bit of haze from the internal elements. The 210 is of 6/6 construction which I soon realized when I had all the spacers and elements strewn about the table. I managed to reassemble it correctly after two attempts. The 150 has 6 elements in 4 groups like a typical plasmat. My 305 g claron is the same construction as the 150.

The 150 will just clip the corners on 8x10, while the 210 still covers with maximum rise on the Deardorff. This confirms what others have reported regarding coverage of these lenses.

[Kerry L. Thalmann]

Harold,

Thanks for the additional data points concerning the construction and coverage of the Graphic Kowa lenses. It's nice to have positive confirmation of what I saw when I was counting reflections (which can be a bit tricky if you aren't careful). I was surprised to see that the 150mm and 210mm Graphic Kowas were different designs, but this confirms it beyond any doubt.

That still leaves the questions about Computar vs. Graphic Kowa coverage. Jim has offered the loan of his lenses for a 210mm shoot out at the LF conference, and I can bring my Graphic Kowa and late (6/4) G Claron. However, we still need someone with an 11x14 camera, holders, film and the means to develop it to complete the experiement. Anybody?

Kerry

[luca_3797]

"210mm Computar, 456mm

240mm Computar, 523mm

300mm Computar, 655mm

Though not tested the 270mm Computar should cover about 590mm.".....

Only if they are optimized at 1:1, I suppose.
Or is this list below wrong?

http://216.109.117.135/search/cache?p=computar+240&toggle=1&ei=UTF-8&u=www.seanborman.com/personal/photo/LF_lens_list.html&w=computar+240&d=7A3D91192E&icp=1&.intl=us

thanks for any clarification

[Kerry L. Thalmann]

Only if they are optimized at 1:1, I suppose. Or is this list below wrong?

Luca,

The numbers Sandy quoted are for infinity. I have seen the specs in the link you provided before and they are very conservative in the case of the Computars. For example, I have a 150mm Computar that I have shot on 4x10 - which requires an image circle of abour 266mm just to hit the corners of eth format. From my experience, I can say that the 150mm f9 Computar covers 4x10 easily, with room for movements. In this case, the actual coverage is much greater than the 218mm image circle listed in the link you provided.

This situation is similar to the G Clarons. Schneider conservatively listed the coverage as 64 degrees, but many people happily use them out to 80 degrees of coverage.

As these lenses were originally intended for reproduction work at magnifications around 1:1, a very demanding application, the manufacturers tended to be very conservative in their coverage specs. While the performance may taper off gradually beyond the manufacturer's specs (64 degrees for the G Claron, 72 degrees in the case of the 150mm f9 Computar), it can still be more than adaquate for less demanding general pictorial use - especially if the final result is a contact print.

Kerry

[Kerry L. Thalmann]

More Reflections...

Today I received a 210mm f9 Computar and can say without a doubt that the construction is different than my 210mm Graphic Kowa (see above - six reflections per half = 6/6 construction).

Here's the info on the new lens:

210mm f9 Computar (serial number 503xxx) - Five reflections per half in the classic plasmat pattern (4 bright, 1 dim). Also, the lens elements are slightly smaller in diameter than my 210mm f9 Graphic-Kowa.

At first glance, these lenses appear identical, but further inspection reveals that they are different both optically and mechanically.

So, what about coverage? The largest camera I currently have is an 8x10. I do expect to be getting an 11x14 in the next month for review. When I do, I will put both lenses on it and do some test shots.

Kerry

[Kerry L. Thalmann]

Rather than start yet another Computar/Graphic-Kowa thread, I thought I'd revive this one in an effort to keep all the info in one place.

This evening, I won an eBay auction for a 270mm f9 Graphic-Kowa. I was the only bidder and the price was reasonable (the seller had listed it twice previously with a starting bid 2x what I paid for it). As anyone who has followed this thread knows, there is quite a bot of confusion regarding the coverage of the various permutations of the Computar/APO Kyvytar/Graphic-Kowa lines. Consenus seems to be that all (or at least most) f9 Computars are 6/4 designs that cover ~95 degrees. Sometime around 1980, give or take, during the brief period when these lenses were sold under the APO Kyvytar, the design of some focal lengths changed to 6/6 and usable coverage was reduced to ~85 degrees. Some Graphic-Kowas (most, or all 150s and a few 240s, according to user reports) were the older, higher coverage 6/4 design, but most Graphic-Kowas (including my 210mm) are the newer 6/6 design. I bought this 270mm Graphic-Kowa hoping that it:

a) fits directly in a Copal No. 3S shutter
b) is the higher coverage 6/4 design

Given the limited data set, I have no way of knowing if either of these will be true until I get the actual lens in my hands. Thankfully, I didn't pay an exhorbitant amount ofr this particular sample. In other words, I placed a bid on a hope and a prayer.

This got me thinking, given the collective wisdom of this forum, and the number of Computar/APO Kyvytar/Graphic-Kowa owners who have posted in this thread, perhaps we could begin accumulating enough data to take the guess work out of buying these lenses sight unseen. I'm thinking of a database based on lens serial numbers - I've noticed there seem to be multiple serial numbering sequences employed over the years/brands and am hoping with enough data maybe we can establish some patterns.

So, if you own any of these lenses, please post:

1) Focal Length (150mm, 210mm, 240mm, 270mm, 305mm, 360mm, 480mm)
2) Maximum Aperture (usually f9, but some of them in shutters were labeled f6.8)
3) Brand Name (Computar, APO Kyvytar, Graphic-Kowa)
4) Lens serial number (all six digits would be most helpful, but if that makes you uncomfortable, the first three digits followed by xxx is better than nothing. Or, email me the full serial number and I'll use it to help establish trends, but not post it publically)
5) Are the cells a direct fit in a standard shutter (Copal No. 1 or Copal No. 3S)
6) Approximate coverage (I know this is a bit subjective, but if a lens vignettes the corners of 8x10, then is obviously doesn't cover the format. So, post the results of actual tests in the form : covers 7x17 with some movement, covers 8x20 straight-on, clips the corners of 8x10 by about an inch. These types of results are close enough to differentiate between ~95 and ~85 degrees of coverage)
7) Lens Construction (6/4 or 6/6) based on the number and type of reflections (counting reflections can be tricky - see earlier posts in this thread. If you're not sure, just say NA fpr Not Available).

Who knows, it may take years to accumulate a signifcant data set, and we still may not know anything more than we do now. Or, perhaps we will be able to establish some patterns, hopefully based on serial numbers.

Thanks in advance for your help.

Kerry

[tim atherton]

I've got two of the Kowa 210's and a Kowa 150mm - when I've got time I'll put the info together

[Kerry L. Thalmann]

I've got two of the Kowa 210's and a Kowa 150mm - when I've got time I'll put the info together

Tim,

Thanks. I probably should have had my own data ready to share before I made my post, but I wanted to get people thinking about testing their lenses and sharing the results. I personally have 150mm samples of all three brands, 210mm in both Computar and Graphic-Kowa, a 240mm Computar and now the 270mm Graphic-Kowa on the way. I've only used the 150mm and 210mm lenses on 4x10 so far and I know the 240mm covers 7x17, but haven't pushed the movements to see how much headroom it has. I need to test these guys on bigger film to see just how large their image circles are.

Kerry

[Diane Maher]

Kerry,
I have a 210 Graphic-Kowa which I intend to use on my 5x12, but it's at Grimes at the moment, getting a scale made for it and also having the shutter/aperture adjusted. The lens is in a Prontor Press Polaroid shutter. Lens serial number is 228xxx.

[sanking]

Kerry,

Here is what I have. If you need the full serial numbers contact me by email.

Sandy


1) Focal Length.

I have 210mm, 240mm, 270mm and 305mm Computars.

2) Maximum Aperture (usually f9, but some of them in shutters were labeled f6.8)

All my Computars in barrel were f/9. In shutter they will open up to about f/6.8 if the shutter allows it.

3) Brand Name (Computar, APO Kyvytar, Graphic-Kowa)

Computar all.

4) Lens serial number (all six digits would be most helpful, but if that makes you uncomfortable, the first three digits followed by xxx is better than nothing.

210mm 5031**
240mm 5005**
270mm 5009**
305mm 5005**


5) Are the cells a direct fit in a standard shutter (Copal No. 1 or Copal No. 3S)

The 210mm fits directly in a Copal 1, the others directly in Copal 3.

6) Approximate coverage (I know this is a bit subjective, but if a lens vignettes the corners of 8x10, then is obviously doesn't cover the format.

210mm Covers (just) 11X14 at infinity, 7X17 (just) at hyperfocal distance
240mm Cover 7X17 with about two inches of movement.
270mm Covers 8X20 with movement, 12X20 (just) at hyperfocal distance.
305mm Covers 12X20 with about two inches of movement

7) Lens Construction (6/4 or 6/6) based on the number and type of reflections (counting reflections can be tricky - see earlier posts in this thread.

All are plasmat or split-Dagor design.

[Kerry L. Thalmann]

Darr,

Please post the info on your lens once you get it back and hve a chance to use it.

Kerry

[Kerry L. Thalmann]

Sandy,

Thanks for sharing the info on your lenses. I was hoping you'd chime in. That's quite a set you've got there. If you know any other ULFers that have Computars, APO Kyvytars and/or Graphic-Kowas, please encourage them to share the info on their lenses. I'm especially interested in data on the 240mm Graphic-Kowas. Some online reports suggest that at least some of them have as much coverag as the 240mm Computars. I'd like to get confirmed coverage and serial number data from owners of these lenses.

Kerry

[Kerry L. Thalmann]

I don't have complete coverage data on my lenses, yet. Nor has my 270mm Graphic-Kowa arrived, but I'll share what I have now and update it when I have the complete data.

150mm f9 Computar Convertible
Serial Number 5005xx
In original Copal No. 1 shutter with dual (150mm/264mm) aperture scales
Covers at least 4x10, possibly more
6/4 construction (based on counting reflections)

150mm f9 Computar
Serial Number 5009xx
In non-original Copal No. 1 shutter with improper aperture scale (likely originally a barrel mount lens transferred to a shutter from another lens)
Covers at least 4x10, possibly more
6/4 construction (based on counting reflections)

150mm f6.8 APO-Kyvytar Convertible
No Serial Number
In original Copal No. 1 shutter with dual (150mm/264mm) aperture scales
Covers at least 4x10, possibly more
6/4 construction (based on counting reflections)

150mm f9 Graphic-Kowa
Serial Number 1530xx
Originally supplied in barrel, remounted in a Copal Press No. 1 shutter by SK Grimes
Covers at least 4x10, possibly more
6/4 construction (based on counting reflections)

210mm f9 Computar Convertible
Serial Number 5030xx
In original Copal No. 1 shutter with dual (210mm/370mm) aperture scales
Covers at least 8x10
6/4 construction (based on counting reflections)

210mm f9 Graphic-Kowa
Serial Number 2261xx
Originally supplied in barrel, remounted in a Copal Press No. 1 shutter by SK Grimes
Covers at least 8x10
6/6 construction (based on counting reflections)

240mm f9 Computar
Serial Number 5005xx
In original Copal No. 3 shutter
Covers at least 7x17
6/4 construction (based on counting reflections)

270mm f9 Grapjic-Kowa
Serial Number 5205xx
In original barrel
Coverage unknown
Construction unknown

That's what I've got so far. I''ll try the 270mm Graphic-Kowa cells in a Copal No. 3 shutter and check the construction when it arrives.

Please keep the data coming (tell your friends). We're off to a great start, but definitely need a lot more data to establish any patterns.

Kerry

[Uli Mayer]

I have those:

Graphic-Kowa 1:9 / 305
# 512355
in original barrel with filter slot
stops 9-45
flange thread 60.7mm
covering 8x10 plus 6cm shift to each side ( camera's limits)
5 reflections with each cell

Graphic-Kowa 1:9 / 210
# 227538
in non-original shutter Synchro-Compur # 1
covers 8x10 plus 2,5cm shift to each side (then strong vignetting occurs)
4 reflections with each cell

and this heavy beast:

Graphic-Kowa 1:4.5 / 150
# 522271
in original barrel
total length 53mm
filter thread 55mm
mounting thread 60,7mm
stops from 4.5 - 45
covers an image circle of approx. 260 mm
4 reflexions / cell

A big THANK YOU! to you ,Kerry, for initiating this compilation endeavour!
Uli

[sanking]

Sandy,

Thanks for sharing the info on your lenses. I was hoping you'd chime in. That's quite a set you've got there. If you know any other ULFers that have Computars, APO Kyvytars and/or Graphic-Kowas, please encourage them to share the info on their lenses. I'm especially interested in data on the 240mm Graphic-Kowas. Some online reports suggest that at least some of them have as much coverag as the 240mm Computars. I'd like to get confirmed coverage and serial number data from owners of these lenses.

Kerry

Kerry,

I applaud your efforts in trying to solve this enigma. My primary motivation in starting this thread was to bring the qualities of Computar lenses to the attention of eveyone so that certain persons would not continue to hoard them and sell them at exhorbitant prices. Since *some* Kowa Grahic lenses have the same formula, and are often availabel for considerably less than Computars, I really appreciate what you are doing.

I have personally tested some 8-10 Kowa Graphics in 240mm and 270mm that folks sent me to see if they measured me to the Computar. About half did, so there are really some bargains out there for astute buyers. So far, none of the 305mm Kowa Graphics I have tested have as much coverage as my 305mm Computar.


Sandy

[Kerry L. Thalmann]

Kerry,

I applaud your efforts in trying to solve this enigma. My primary motivation in starting this thread was to bring the qualities of Computar lenses to the attention of eveyone so that certain persons would not continue to hoard them and sell them at exhorbitant prices. Since *some* Kowa Grahic lenses have the same formula, and are often availabel for considerably less than Computars, I really appreciate what you are doing.

I have personally tested some 8-10 Kowa Graphics in 240mm and 270mm that folks sent me to see if they measured me to the Computar. About half did, so there are really some bargains out there for astute buyers. So far, none of the 305mm Kowa Graphics I have tested have as much coverage as my 305mm Computar.


Sandy

Sandy,

Thanks for your kind words and support. It is exactly the reasons you describe that lead me to solicit input from others to see if any patterns can be established to help determine which lenses have large coverage and which do not.

With that in mind, here's an additional data point for my recently acquired 270mm Graphic-Kowa:

270mm f9 Graphic-Kowa
Serial Number 5205xx
In original barrel - Cells are not a direct fit in any standard shutter. The front cell is to big for a Copal No. 3S and too small for a regular Copal No. 3. To make matters worse, the rear cell is an integral part of the lens barrel and cannot be removed without cutting it free from the barrel.
Coverage unknown - haven't had a chance to test it yet
Construction - based on the reflection, it appears to be a 6/4 plasmat. So, I'm hopeful it will have the same generous coverage as Computars.

As an additional point of reference, it sounds like the same design Tracy Storer describes in a different thread on this subject:

"I have a 270mm Graphic-Kowa. I checked mine ages ago at f/22 and found it to throw about a 19" circle. 11x14, but not 12x20. There were different variations at least in the mounting of these lenses. The rear cell of my 270, for example, is integral to the barrel, and the front cells threads don't fit a #3 or #3S shutter. (at least I got it cheap)".

So, I'm hoping it will cover at least 7x17, which needs an image circle of about 18". Maybe it will cover a bit more stopped down to f45.

Kerry

[Oren Grad]

Kerry - I have a 270 Graphic Kowa, S/N 5201xx, in an odd barrel-mount with very wide "skirts", one of which is integral with the aperture-setting ring. It's marked, and closes, only to f/45. Haven't had a chance to cobble it on to a lensboard and test it yet.

Looking at the reflections of the overhead incandescent lamp in the front cell, I see four: a very small one that looks purplish or bluish depending on the angle; a closely-spaced very small pinkish one; a larger, more distantly-spaced yellowish one, and a still larger, distantly-spaced neutral one. Rear cell looks similar.

With the front cell removed, the opening in the front of the barrel measures just a hair less than 57mm.

I don't know about the rear cell - I can't get it to budge just by twisting with my hands, and I'm not inclined to attack it with a strap wrench just now.

At least I got it cheap... ;)

Thanks to you, Sandy and all for compiling and sharing this information.

[Kerry L. Thalmann]

Oren,

Other than the reflections (which can be tricky to count - more on that below). yours sounds exactly like my "new" 270mm Graphic-Kowa. As far as mounting it to a lens board, if yours is like mine, the "mounting flange" complete with raised lip is a perfect fit in a lens board drilled for a Copal No. 3 shutter. That was a pleasant surprise. I'll need to drill and tap four small holes for the screws to mount the flange to the board, but fortunately I've accumulated a small stack of Sinar/Horseman lensboards over the years and three just happen to have Copal No. 3 holes in them (I mount most of my barrel lenses on Sinar boards to use with a Sinar behind-the-lens shutter).

Counting reflections can be tricky business. If the light source is too large or too far from the lens you can miss one or more reflection. For that reason I use a small single white LED held close to the lens surface when counting reflections. Using this method, I definitely see five reflections per cell for my 270mm Graphic-Kowa, not the four you observed. The colors of my reflections are different (probably due to the differing color temperatures of our light sources). I see four bright reflections that are all similar in color (pale lavendar) and a fifth larger, dimmer reflection (when moving the LED closer to the lens cell) that is a bit more yellow than the other four. You may be missing this fifth refection (the one from the cemented surface) due to your light source being further away. I had the same problem the first time I tried counting the reflections in some of my 150mm lenses (including my G Claron, which I KNOW is a plasmat and my 150mm Graphic-Kowa). If you get a chance, try re-counting the reflection in your lens using a small "point source" closer to the lens.

A smal light source held close to the lens also helps eliminate missing a second closely-spaced overlapping reflection. For example, my 210mm Graphic-Kowa has six reflections per cell (indicating three air-spaced elements per cell for a 6/6 contstruction), but two are practically right on top of each other. With the small LED held close to the surface of the lens, I can definitely tell that they are two distinct reflections (probably the result of a very thin air-space between two adjacent glass surfaces). With a larger light source further from the lens cell it's easy to mistake these two overlapping reflections for one single reflection, or miss them all togther if the light source is more than a few feet away.

Kerry

[Diane Maher]

Kerry,
I got my lens back from Grimes today. See below. The lens is in a Prontor-Press Polaroid shutter.

Diane

1) Focal Length: 210mm
2) Maximum Aperture: f9
3) Brand Name: Graphic-Kowa
4) Lens serial number: 228095
5) Are the cells a direct fit in a standard shutter: The lens cells fit directly into a Copal 1 (it is the same Copal 1 that my 240 G-Claron is in)

6) Approximate coverage: Not sure yet, haven't had time to shoot. Will try and do some testing with it soon on my 5x12.

7) Lens Construction (6/4 or 6/6) based on the number and type of reflections (counting reflections can be tricky - see earlier posts in this thread. If you're not sure, just say NA fpr Not Available). I'm not sure, but it looks like there are five reflections (front and rear), and that is counting the one of the source on the surface of the lens when it is blinding me.

[Joe Forks]

Sorry to resurrect another old thread, but does anyone know the answer to these two questions:

1) what is the image circle on Graphic Kowa 360 F9 in a copal 3s shutter?
2) will the 360 F9 become F6.8 in a 3s shutter?

Thanks in advance, I've been reading these old threads for over an hour and so now it's time to just ask! :)

Best
Joe

[rob]

I have kowa 360 f9 in barrel. It has similar reflections as my repro-claron. Therefore, it is a 4 element, 4 group dialyte construction, so coverage is probably about 50 degrees.

[Joe Forks]

I have kowa 360 f9 in barrel. It has similar reflections as my repro-claron. Therefore, it is a 4 element, 4 group dialyte construction, so coverage is probably about 50 degrees.

Thanks Rob,
I was considering a shutter to share between 305 and 360 cells but I think I'll leave em in barrel.

Best
Joe

[Asher Kelman]

Sorry to resurrect another old thread, but does anyone know the answer to these two questions:

1) what is the image circle on Graphic Kowa 360 F9 in a copal 3s shutter?
2) will the 360 F9 become F6.8 in a 3s shutter?

Thanks in advance, I've been reading these old threads for over an hour and so now it's time to just ask! :)

Best
Joe

What's the answer anyone?

Thanks,

Asher

[Tracy Storer]

What's the answer anyone?
Thanks,
Asher

Asher, I have been meaning to check the coverage of my 360 Kowa.....will do soon. Then will sell either the 360 Kowa or the 355 G-Claron. Ditto my 305 Kowa and GC.

[Steve Hamley]

Tracy,

I bet you keep the G-Claron....

Cheers, Steve

[Asher Kelman]

Could be that the Kowa has a better coating, LOL! After all, these were the most mature of the line. Next, if the G Claron has more money locked inside, does that really show in the picture or in the portrait taken with just the rear element.

If not, then it makes more sense to keep the Kowa and harvest the hidden $ in the G-Claron.

Asher

[Tracy Storer]

When I get a chance to do the side by side comparison, "usable" coverage will be a factor for sure, but will not be the only deciding factor for me.

[Kerry L. Thalmann]

I've never seen a 360m Graphic Kowa that wasn't a 4/4 construction with MUCH narrower coverage than the 6/4 Computars and also considerably narrower angle of coverage than the 6/6 210mm Graphic-Kowas.

In terms of coverage, the 360mm Graphic-Kowa will be much closer to a 14" Red Dot Artar than the ULF-capable Computars (about 95 - 96 degrees), or even a G Claron (about 80 degrees). I know some sellers on eBay, who have never actually shot with one of these lenses, will make all kinds of crazy inflated coverage claims, but it's basically a very nice, compact, single coated 8x10 lens that's a direct fit in a reasonably modern Copal 3S shutter. It might be usable on 11x14, if you don't mind the corners going a little soft, but if you need 11x14 (or greater) coverage, there a LOT of better choices in the 355mm/360mm/14" focal length range (355mm G Claron, 14" f7.7 Dagor, 14" f11 Trigor, 355mm/360mm Convertible Symmar, 360mm APO Gerogon, 360mm f6.3 Fujinon-W, etc.).

The problem is all of these lenses (f9 Computars, f6.8 APO KYVVYTARs and f9 Graphic-Kowas) all look exactly alike, but unless you count reflections and determine the construction of the lens (6/4, 6/6 or 4/4 - in descending order of coverage), you won't really know what they cover.

Obviously, I haven't seen every sample of every lens in every focal length, but all f9 Computars I've seen, in all focal lengths, are 6/4 construction with enormous coverage. All 150mm f6.8 and 150mm f9 Graphic-Kowas I've seen are 6/4 construction with an observed usable image circle of about 290mm (I shot for years with a 150mm f9 Graphic-Kowa on 4x10 and it covered with room for modest movements). All 210mm f9 Graphic-Kowas I've seen are 6/6 construction with a usable image circle of around 380mm (compared to about 450mm for the 210mm f9 6/4 Computar). Some 240mm Graphic-Kowas I've seen are 6/4 and some are 6/6. And, as I said above EVERY 360mm Graphic-Kowa I've seen is a 4/4 design with much narrower coverage.

Better even than counting reflections is putting the lens on a camera and exposing some film and examining the results with a loupe. If possible, compare a few different types of lenses (Graphic-Kowa, G Claron, Fujinon-W, Dagor, Convertible Symmar etc.) with the lens centered and again with a couple inches of front rise and/or shift and examine the corners of the negatives with a loupe to determine which offers the most usable coverage.

On the longer focal length Computars (240mm, 270mm and 305mm), my experience echos the coverage numbers Sandy quoted earlier in this thread.

In my experience, in this focal length range, the G Claron offers the best compromise in terms of size, cost and coverage. If you don't mind the heavy weight and enormous filter size, the 355mm/360mm Convertible Symmar (officially, just plain Symmar) offers the best combination of price and coverage. Sany clued me into this one several year ago. It is readily available in barrel and a variety of shutters (Compound, Ilex and Copal - depending on age) at VERY reasonable prices and offers huge coverage - even more than the smaller G Claron. The only bad things I can say about the 355mm/360mm Symmar are: it's big and heavy; and it tends to develop contrast robbing haze on the inner surfaces of the air-spaced elements. This is easily removed by any competent lens repair technician.

Kerry

[Asher Kelman]

From the large format department of Lens and Repro we are offering this 360mm f9 Graphic Kowa in excellent condition. The lens is mounted in a Copal 3S shutter. Glass is clean with no cleaning marks, scratches, haze or recementing issues. Shutter works properly and the aperture scale is calibrated in 1/3 stops with stops indicated down to f90 with 1 1/2 more uncalibrated stops. The Graphic Kowa lenses were the 3rd reincarnation of the original Computar lenses imported by Jack Callahan of KYVYX Korporation in the early 1980's. They were later called the Apo-Kyvytar and then the Graphic Kowa. They are 6 element symmetrical Plasmats with an image circle which increased to 86 degrees as the lenses were stopped down. Great for ultra large formats they are physically small as well. Now is your chance to buy one of these highly regarded lenses. Original lens hood, front and rear lens caps and the mounting flange are included. Check our ebay store and www.lensandrepro.com for more large format cameras, accessories and the largest selection of used view camera lenses in the US (including a 305mm f9 Graphic Kowa). Sold as described, final sale."



whereas Jm Galli advertises one for us in APUG as a more sober price of $595 and no one is taking it! I have suggested to him it might move faster next to this so well hyped up lens and repro specimen! Amazingly, the price direct from the Lens and Repro store is $1550, whereas on ebay one can grab it for a mere $1300!

I have one on the way for myself for $560 total, lens and Copal S shutter. My needs are satisfied with 8x10 but I'd have preferred to have a much wider coverage. I have yet to see any pictures with these lenses! I'd love the flexibility of being able to use this for 11x14, 16x20 and even 20x24! That would be a great lens!

Asher

[Steve Hamley]

I've owned one example, and it was not a plasmat. The 360mm Kowas were 4/4, like the Artar. They're great lenses, but trying to get much, if any more sharp coverage out of the 360mm Kowa than a 14" Artar is most likely wishful thinking.

If you buy a 360mm Kowa with the expectation you'll have 90 degrees or more of sharp coverage, be sure you can return it.

Cheers, Steve

[Asher Kelman]

I've owned one example, and it was not a plasmat. The 360mm Kowas were 4/4, like the Artar. They're great lenses, but trying to get much, if any more sharp coverage out of the 360mm Kowa than a 14" Artar is most likely wishful thinking.

Steve,

I've chose the 360mm Graphic Kowa just to cover generously 8x10 at its focal lengths; rear cell and complete lens. My current lenses have limitations in uniform, non-vignetting coverage, so this 360mm Graphic Kowa, for just $315 for the pristine lens & hood, (and Copal 3S on the way), is going to be my general workhorse, where I can have whatever movements I need, without limitations. What's interesting is the many statements of ownership. Even Jim Galli! However, I've searched and haven't found any pictures taken with this so much praised optic!

Still, I'm happy to learn of other such lenses with giant FOV and stellar optics! That's for my Camera Obscura where film or Cibachrome paper will go on a vacuum board and there are no film holders.

Asher

[Chauncey Walden]

Kerry, to add one more to your list, I have a 270mm Graphic-Kowa and it appears to be a 4/4. Never tried it on a camera, was keeping it around to use on an enlarger someday.

[Kerry L. Thalmann]

From the large format department of Lens and Repro... The Graphic Kowa lenses were the 3rd reincarnation of the original Computar lenses imported by Jack Callahan of KYVYX Korporation in the early 1980's. They were later called the Apo-Kyvytar and then the Graphic Kowa. They are 6 element symmetrical Plasmats with an image circle which increased to 86 degrees as the lenses were stopped down. Great for ultra large formats...

Don't belive everything you read...

I bought my 360mm f9 Graphic-Kowa from Lens & Repro many years ago based on the same optimisitc coverage claims. I tracked down a Copal 3S sutter and had custom engraved aperture scales made by the late Steve Grimes. My goal was a nice 360mm lens for 11x14, and possibly larger formats.

After all this trouble and expense, when I actually put the lens on the camera and tested it, I was very disappointed in the actual usable coverage. It was MUCH less than the claimed 86 degrees, and not really suitable for ULF (MAYBE 11x14 contact printing, definitely 10x12, if that's considered ULF). As I mentioned in my previous post, there are many better choices in this focal length range for 11x14 and larger formats. The tested lens illuminated 11x14 and 7x17, but that was the max. Chris Perez tested it on his 12x20a and it wouldn't come close to covering that format.

I verified that the construction was 4/4, and definitely NOT a 6/4 plasmat. Several other owners of this lens have also veriified that their samples are also 4/4 construction with coverage similar to a 14" Red Dot Artar. Other than inflated advertising claims, I'm not sure why this issue is still being debated.

The 360mm Graphic-Kowa is a 4/4 design with coverage consistent with other lenses of similar construction - no more, no less. It does have the advantage that the cells are a direct fit in a modern Copal 3S shutter, and it takes standard threaded filters. It makes a very fine lens for 8x10.

I happen to have a Kyvyx Korporation Katalog from 1980 that has specs and comments from Jack Callahan on these lenses. The specs are comments are full of inconsistencies, peculiarities and errors. The design and construction of these lenses was in flux at that time, and I suspect Jack Callahan himself didn't even know exactly what changes the OEM that produced these lenses was implementing at any given moment. But, from his comments, he knew the 305mm and 360mm APO Kyvytars he was selling had substantially less coverage than the some of the shorter focal lengths in the same series.

In a letter signed by J. D. Callahan, he states the coverage of the APO-Kyvytar lenses as:

"The 1/2 field angle is 38 degrees".

This is equal to a coverage angle of 76 degrees.

In the price sheet, the coverage is listed as:

"The field angle is up to 86 degrees".

The spec sheet is where things get really confusing. The Field Angle for all focal lengths from 150mm - 480mm is listed as "up to 86 degrees". However, the Image Size at Inifinity (image circle) is inconsistent. For the 150mm, 210mm and 240mm focal lengths, the specified image circles (277mm, 386mm and 438mm) are pretty close to what you'd get using an 86 degree coverage angle. However, the listed image circle for the 270mm APO-Kyvytar is much bigger (591mm) and equates to 95 degrees of coverage. BTW, this is consistent withe the usable coverage Sandy reported for the 270mm f9 Computar and also my own personal experience with the 270mm f9 Computar. The image circle specs listed for the 305mm, 360mm and 480mm APO Kyvytars are much smaller (relative to focal length). They are 443mm, 523mm and 698mm - which correspond to an angular coverage of 72 degrees for these focal lengths.

And, there is an asterisk in the 270mm column of the spec table. The note associated with that asterisk says:

"It should be pointed out that the APO-KYVYTAR CONVERTIBLE 6.8/270 in Cop III covers more than either the 305mm or 360mm and costs far less".

There are no details provided anywhere in the catalog about the construction of the lenses, or why some focal lenths cover substantially less than others. But, from the above quote, it is very clear that Jack Callahan knew some of the lenses performed differently than others. Given that this was a transitional period between the f9 Computars and the Graphic-Kowas, I wouldn't really believe any of the specs listed in the table and would recommend testing the coverage of any lens you plan to buy - or ask any seller that claims enormous coverage to put it on a 12x20, or larger camera, focus at infinity, take a test shot and either scan the negative or send it to you for inspection.

From the anecdotal evidence, it's clear that the construction of some of these lenses changed over time (the 210mm F9 Computars were 6/4, the 210mm Graphic-Kowas were 6/6 - some for the 240mm Computar and SOME 240mm Graphic-Kowas were 6/4). Since the vast majority of these lenses were sold in barrels, I suspect many were targeted for use on process cameras, and were probably built to order based on the required specs of these large customers. That may explain why some of the designs changed over time.

In any case, not all Computars, APO-Kyvytars and Graphic-Kowas are created equal. Count those reflections and test those lenses. It's the only way to know for sure what they are capable of covering.


"Sold as described, final sale."

So, what if the lens received is not as described. What if the 360mm purchased from Lens and Repro is not a 6/4 wide field plasmat? What if it is a 4/4 with much narrower coverage. One would hope they would take it back and issue a full refund. After learning the true coverage of the 360mm Graphic-Kowa I purchased from them, I never tried to get my money back. I just kept it for a while and used it on 8x10. It was a fine lens for that application.

[/quote]My needs are satisfied with 8x10 but I'd have preferred to have a much wider coverage. I have yet to see any pictures with these lenses! I'd love the flexibility of being able to use this for 11x14, 16x20 and even 20x24! That would be a great lens![/quote]

And, it wouldn't be a 360mm Graphic-Kowa. The 305mm f9 Computar easily covers up to 16x20. I had two and they were absolutelyt amazing. I recently sold both. Off the top of my head, I can't think of any lens in the 300 - 360mm focal length range that covers 20x24 at infinity. Maybe a long Series V Protar, but the coverage specs of those lenses tended to decrease with focal length. In the 360mm focal length, you'd need a lens with 96 degrees of coverage to hit the corners of 20x24. A 300mm would need 106 degrees of coverege for 20x24.

Kerry

[Asher Kelman]

Don't believe everything you read...

I bought my 360mm f9 Graphic-Kowa from Lens & Repro many years ago based on the same optimisitc coverage claims. I tracked down a Copal 3S sutter and had custom engraved aperture scales made by the late Steve Grimes. My goal was a nice 360mm lens for 11x14, and possibly larger formats.

After all this trouble and expense, when I actually put the lens on the camera and tested it, I was very disappointed in the actual usable coverage. It was MUCH less than the claimed 86 degrees, and not really suitable for ULF (MAYBE 11x14 contact printing, definitely 10x12, if that's considered ULF).

It's unfortunate to hear your disappointment with the description and performance that differ so much. I had taken Lens & Repro as a reputable firm source and I feel let down as i have always believed their descriptions.


I verified that the construction was 4/4, and definitely NOT a 6/4 plasmat. Several other owners of this lens have also veriified that their samples are also 4/4 construction with coverage similar to a 14" Red Dot Artar. Other than inflated advertising claims, I'm not sure why this issue is still being debated.

Exactly! It's the ads that really piss me off! LF is a community thing!


The 360mm Graphic-Kowa is a 4/4 design with coverage consistent with other lenses of similar construction - no more, no less. It does have the advantage that the cells are a direct fit in a modern Copal 3S shutter, and it takes standard threaded filters. It makes a very fine lens for 8x10.

That is perfect for much of my use! Also there's the claimed bonus of using the rear cell as a longer portrait lens. I hope that, at least is a valid proposition.


[/B]I happen to have a Kyvyx Korporation Katalog from 1980 that has specs and comments from Jack Callahan on these lenses. The specs are comments are full of inconsistencies, peculiarities and errors.

From the anecdotal evidence, it's clear that the construction of some of these lenses changed over time (the 210mm F9 Computars were 6/4, the 210mm Graphic-Kowas were 6/6 - some for the 240mm Computar and SOME 240mm Graphic-Kowas were 6/4). Since the vast majority of these lenses were sold in barrels, I suspect many were targeted for use on process cameras, ....

That might also explain the disparity in claimed coverage as process lenses are often specified for coverage at 1:1 and not at infinity, hence that major difference?



My needs are satisfied with 8x10 but I'd have preferred to have a much wider coverage. I have yet to see any pictures with these lenses! I'd love the flexibility of being able to use this for 11x14, 16x20 and even 20x24! That would be a great lens!


And, it wouldn't be a 360mm Graphic-Kowa. The 305mm f9 Computar easily covers up to 16x20.

At what magnification?


Off the top of my head, I can't think of any lens in the 300 - 360mm focal length range that covers 20x24 at infinity. Maybe a long Series V Protar, but the coverage specs of those lenses tended to decrease with focal length. In the 360mm focal length, you'd need a lens with 96 degrees of coverage to hit the corners of 20x24. A 300mm would need 106 degrees of coverege for 20x24.

Kerry

My needs for such a extraordinary wide coverage lens are for one learning stage in my transition to new studio portrait work with my camera obsucra. In this use, the film is on a vertical vacuum board in the next room, but not in a film holder, so I can change from one format to any other. I'd be happy being able to work at lens to subject distances of 4ft to 12ft and get coverage up to 20x24 of a person initially. (Subsequently, using much longer process lenses, I'll be using 50" wide paper, 74"-80" or so high). For now, now, 20x24 is all I'm aiming for. That's the max size I'm set up to process myself. So your suggestions of a 305mm Computar or the long series V Protar are much appreciated and worth considering for this stage of my Camera Obscura work.

Thanks for so generously sharing your hard-earned experience on the entire series of Computar to Kyvyx and Kowa lenses! This will be a great resource for a lot of folks to come.

Asher

[Lynn Jones]

Hi Guys,

I worked for DO/Fujinon/Graphic-Kowa, Later VP of BBOI/B&J, still later stareded my own company in Texas.

The Graphic Kowa's and APO Computars with 150, 210, 240, 305 were all 6 element plasmats covering around 85-90 degrees. The were wonderful lenses (I still have 4 or 5 of them). In those days (up until around 78-80) the 360 was a very different lens designed for some kind of special graphic arts camera that only covered around 5x7 or so.

After the demise of BBOI/B&J, the owner/president and my career long friend, J.D. "Jack" Callahan started Kyvytar in Jersey and then moved to California. He had a deal with Kowa and he may have had some additional KGraphics made under his name.

By the way, the Computar Symmetrigons were 4 element metrogon/topogon types covering about 70+ degrees optimized between 1:2 to inf, f 6.3. The principal developers were JanTerLuow, Dr. John Lawson, and to a lesser extent me. These were created to be competitive with typical plasmats at lower cost and were quite successful until the loss of the above companies.

Lynn

[Jim Graves]

... The Graphic Kowa's and APO Computars with 150, 210, 240, 305 were all 6 element plasmats covering around 85-90 degrees. ...


Lynn ... You don't mention the 270mm ... plasmat also???

[Lynn Jones]

Lynn ... You don't mention the 270mm ... plasmat also???

Yes, sorry, that one too.

Lynn

[Vaughn]

...
By the way, the Computar Symmetrigons were 4 element metrogon/topogon types covering about 70+ degrees optimized between 1:2 to inf, f 6.3...
Lynn

One of these (210mm/6.3) came with my new 4x5 (Indian clone of a Deardorf Special) back in the early 1980's. What a sharp crisp lens it was! I use one for 5x7 now.

Vaughn

PS -- Jim, I'll give that 270mm a work-out this week-end!

[Asher Kelman]

Don't belive everything you read...

I bought my 360mm f9 Graphic-Kowa from Lens & Repro many years ago based on the same optimisitc coverage claims. I tracked down a Copal 3S sutter and had custom engraved aperture scales made by the late Steve Grimes.

Hi Kerry,

My Copal 3S arrived, (with a pristine 300 mm Congo lens that I'll likely sell). The cells of the 360mm Graphic Kowa fit perfectly into the 3S shutter. I didn't know whether or not to use the thin brass ring spacers.

Did S.K. Grimes use the spacers? On the scale, what was the aperture range? Was it to 6.8? I don't feel I can accurately measure the front cell diameter to determine the lowest f-stop. Did you make a second aperture scale for just using the rear element and what would that focal length be, if you remember?

360mm f9 Serial number 600208
Graphic Kowa
Copal 3S Shutter
Construction: Unknown

Reflections observed:

4 reflections front and rear elements, 2 of them appear as one. So, at first one might think there are just 3. However, one reflection splits as lens is tilted and reflections approach edge and the pair appear separately and there are a total of 4 reflections.

Asher

[John Schneider]

I just got this Computar brochure and thought it might be good to post it here. Interestingly, it only gives the half-field angle, rather than image circle, but the usable image circle has been discussed at length previously in this thread.

[John Schneider]

last page:

[hoffner]

Some useful stuff John, thank you.

[neil poulsen]

This is interesting information. I considered this lens for 8x10. But, after searching and querying, I could not learn whether the reputed, huge coverage of these lenses could stand up to enlarging. Most of the commentary related to contact prints.

[Dan Fromm]

Thanks for posting this John. I've added a link to this page to my list of useful lens-related links, which can be found at: http://1drv.ms/1urNWXL

[ic-racer]

Here you go Sandy (I've got these scattered through different emails that I use to "clip" notes into...) - again, I can't remeber where I clipped it from - might have baan an ebay sale....

"The following is from the beat up information sheet, (a letter) which was packaged with my 305/537 APO-Kyvytar and in the box with the Korona.

It is not dated.

"APO-KYVYTAR lenses are made by the same people in Japan that made the convertibles under the "Computar" trademark which I used to own and which I sold to Chugai International Corporation who use the trademark for their video lenses, enlarging lenses, and the large format taking lenses (Computar Symmetrigons).

The APO-KYVYTARs are the same formula as the former Computar convertibles except that the APO-KYVYTARs are one stop faster, i.e., 6.8 instead of 9.0

The APO-KYVYTARs convert to a focal length just a little less than double the nominal focal length simply by un-screwing the front element and using the rear element.

The APO-KYVYTARs convert in focal length as follows:

>From 150mm to 264mm 210 370 240 422 270 475 305 537 360 633 480 845

The diaphragm scale is a double scale. The second scale is for use with the single rear element. The rear element alone is slightly softer and therefore good for portraits where it is desirable to shoot farther from the subject and soften the texture of the subjects faces.

Both elements together give you the sharpest picture, and flattest field, and the best color that money can buy!"

It is signed by J. Callahan, President, KYVYX Corporation, South Hackensack, NJ."

I've tried my 210 as a 370mm - it' actually pretty nice. But I have only really used it for close-ups of flowers, so the background i all out of fiocus anyway - so not really a scientific test. That said, as a 210mm lens, it's a sharp snappy little bugger

BTW - the Kowa's also become 6.8 once you put them in a shutter (I think Jim Galli forked out for a WA Kowa 6.8 only to find it was exactly the same as his barrel f9 he had, only difference was it was already mounted in a shutter...?)

I was searching for info on Copal #3 shutters and came across this image from a video. I was very curious about the lens rather than the shutter. Turns out it is a picture of a 6.8 305-537 Apo-Kyvitar.
I guess a somewhat rare lens. The only picture of it I could find and one of the few mentions of it was in this old thread.

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