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robertraymer
16-Dec-2018, 19:52
Does anyone have experience with the Kodak 12" Ektar 4.5 (not the apparently more common Commercial Ektar 6.3)?

I understand that it is a continuation/renaming of the Kodak Anastigmat lens design after it was put in a shutter, in this case an Ilex 5. I have also heard that is supposed to be an excellent performer, which would make sense, as I am a big fan of the Kodak Anastigmats I have. Sadly though, I have been using the one that came with my B&J 8x10 and am somewhat disappointed. Looking through the ground glass the image never appears terribly sharp, and I had originally chalked this up to needing new ground glass, but the small number of frames I have had the chance to shoot on FUJI HR-U X-ray have all been very soft, despite being as sharp as possible on the GG. As for the lens itself it is cosmetically beautiful, no scratches, haze, fungus, coating loss, etc. I took it apart and the insides are as nice as the outsides. All elements are in their correct positions and the lens was assembled properly.

I did a small test to try and determine if the issue was with the film, the GG, or something else, not expecting to be questioning the lens itself, but after holding my Fujinon-W 180 5.6 and Dallmeyer 8" Pentac which I love but is not known for its sharpness per se up to a lens board in front of the front standard (not properly mounted and not likely light tight) I found that the Fuji was tack sharp on the GG and even the Dallmeyer performed far better, even wide open at 2.9. So I am wondering if there is something else that could be going on or if I just have a bad copy of the lens.

Thoughts?

Mark Sawyer
17-Dec-2018, 00:09
I have one, a great lens. It was Kodak's top-of-the-line Tessar at the time, but they made more f/6.3 Commercial Ektars, which were also great lenses, but the f/4.5 was the more expensive and arguably more desirable lens in its day. But there was a 14-inch f/6.3, and therefore Commercial Ektar, which is the most popular, and (I think) accentuated the Commercial Ektar's reputation.

Had Kodak made a 14-inch f/4.5 Ektar, would it have eclipsed the 14-inch CE? But there wasn't a timed shutter being made big enough, so Kodak didn't make one. Too bad, because Tessars seem to get better the longer they are. Wollensak made the longest f/4.5 Tessar I know of, 19.5 inches. I'm lucky enough to have one, and it's spectacular.

Mark Sampson
17-Dec-2018, 22:15
I've never seen a bad Ektar, and I've used quite a few (if never the 12" f/4.5). Your lens is at least 51 years old- who knows what may have happened to it? Mechanical damage is not always obvious, and it's also possible that Kodak did send out a bad one. Maybe you could find another example and do an A/B comparison. Without that, or sending your lens to a good repair shop, you may never find out.

leighmarrin
18-Dec-2018, 04:18
I have a 1930s 3x4 Graflex SLR. Its 6" Kodak Anastigmat barrel lens was a little hazy, so I took apart the front cell and cleaned it. When I put it back together, the resulting image was really mushy. I finally realized that I had installed the rear element of the front cell BACKWARDS. Assembled correctly, it is a fairly sharp lens. Could that be what happened to your 12" Ektar?

Mark Sawyer
18-Dec-2018, 11:55
BTW, Kodak got into serious lens making first with the Kodak Anastigmat, which encompassed several designs including the f/6.3 and f/4.5 Tessars. Then they re-named them the Kodak Ektars, which also encompassed multiple designs and speeds. The Commercial Ektars were among the last, and all CEs were f/6.3 Tessars.

Bernice Loui
19-Dec-2018, 08:51
Have two of these 12" f4.5 Ektars, sharp enough at f4.5, by f6.3 - f8 lens performance is Very GOOD..
This focal length combined with the large aperture of f4.5 makes a really GOOD 5x7 head & shoulder_ish portrait lens.

Very possible there is something not proper with the example in question or something not proper with the camera, film holder and other related factors.



Bernice

Mark Sawyer
19-Dec-2018, 10:23
I agree with Bernice, there's something wrong with your particular lens. Kodak had very good quality control, and I doubt they'd let a bad lens out. I'd guess it's misassembled or an element is out of alignment.

robertraymer
21-Dec-2018, 08:33
Thanks everyone.

Im not sure what the issue is. I have a number of the earlier anastigmats and love them, especially their sharpness and quick fall off wide open. I was hoping/expecting the same from the 12" 4.5 and from the sound of it that expectation wasn't wrong.

Im not sure where to go from here. The outside has no damage, even cosmetic, and even if it did it should not effect optical performance. I have unscrewed the front and rear cells to inspect them, but both look very good. Not scratches, haze, fungus, bubbles, separation or anything else that should effect image quality. It also doesn't look as if the cells themselves have ever been taken apart and the elements do appear to be positioned properly. Until I get/make another couple lens boards for my B&J I won't be able to do any side by side comparisons with my other lenses to rule out other factors (film plane, holders, film, etc), but honestly, seeing how I am noticing the difference and softness on the ground glass itself Im thinking maybe I just got a less than perfect copy.

blue4130
21-Dec-2018, 15:56
Could be a spacer was lost over the years? I'd try not fully threading the front element in and see if it improves the sharpness, if so, make some spacers and add as needed until optimal sharpness is found.

robertraymer
22-Dec-2018, 07:19
Could be a spacer was lost over the years? I'd try not fully threading the front element in and see if it improves the sharpness, if so, make some spacers and add as needed until optimal sharpness is found.

I have not known Kodak to use spacers in their lens designs, at least not on any of their other lenses I own or have used, but I was worried that maybe one of the elements was too loose or too tight, so that was one of the first adjustments I tried. Made sure both the front and rear elements were screwed in hand tight (normal tightness for a lens) then slowly loosened each element one at a time while checking the ground glass for sharpness. The lens performs at its best with both elements tightened properly.

Until I have some time for side by side comparisons with my other lenses to completely rule out other factors involving the back or holders I won't know for sure, but Im thinking I may just have one of the rare less than optimal lenses that slipped through Kodak's quality control.

Bernice Loui
22-Dec-2018, 10:56
Kodak Ektars were not made with spacers, Kodak trimmed the lens cell to shutter tube or trimmed the lens barrel which the lens cells to make up the finished lens. If one were to measure the front-rear lens cell spacing on a number of Kodak Ektars, one will discover each one is slightly different in length. This is just one of the many hand crafted and hidden factors that made Kodak Ektars what they are.

Some Ektars still have pencil marks on their lens cells which are assembly notes from when the lens was made.



Bernice

robertraymer
21-Feb-2019, 16:32
Finally had a chance to shoot again today. Im actually thinking that maybe it was just my expectations that are the problem. I have a few of Kodak's earlier anastigmats that I use on my Graflex RB and SpeedGraphic, both of which perform exceptionally wide open. The Ektar, not so much. I compared it to a Rodenstock Sironar N 210 5.6, which is the only other lens I have that will (mostly) cover 8x10 and noticed that the Sironar was tack sharp wide open (much like the anastigmats), where the Ektar did not match it in sharpness until f 11-16. I must say Im a bit disappointed, since I was really hoping to use this lens wide open shooting wet plates, and instead I think Im going to be limited to studio with flash or very bright days.

Jac@stafford.net
21-Feb-2019, 16:58
Kodak Ektars were not made with spacers, Kodak trimmed the lens cell to shutter tube or trimmed the lens barrel which the lens cells to make up the finished lens. If one were to measure the front-rear lens cell spacing on a number of Kodak Ektars, one will discover each one is slightly different in length. This is just one of the many hand crafted and hidden factors that made Kodak Ektars what they are.

Some Ektars still have pencil marks on their lens cells which are assembly notes from when the lens was made.


Solid gold information! Thanks for that.
It should be front page FAQ.

Greg
21-Feb-2019, 17:12
These most probably will not apply to you, but think they are worth mentioning. Three things. 1. Make sure that the rear set of elements is the correct one. Bought a Fujinon lens last year. Image it produced was terrible. Turned out that the rear optics were from another focal length Fujinon. 2. Does it have shims? Once acquired a lens with a lot of shims. Image it produced was mediocre. For the heck of it, removed the shims and the optic demonstratively improved. Who knows why they were added, but I don't think shutter was the original shutter that was sold with the lens. 3. Last off... once bought a lens that gave me a mediocre image at best. Turned out that the front element's retaining ring was very unscrewed and the front element was stuck at its most foward point (think Wollensak Velostigmat with variable soft focus ring), so didn't rattle when you shook the lens.

Tin Can
21-Feb-2019, 17:15
Could we infer from your knowledge that shutter replacement may affect lens performance if not 'zeroed' by an expert?


Kodak Ektars were not made with spacers, Kodak trimmed the lens cell to shutter tube or trimmed the lens barrel which the lens cells to make up the finished lens. If one were to measure the front-rear lens cell spacing on a number of Kodak Ektars, one will discover each one is slightly different in length. This is just one of the many hand crafted and hidden factors that made Kodak Ektars what they are.

Some Ektars still have pencil marks on their lens cells which are assembly notes from when the lens was made.



Bernice

Bernice Loui
22-Feb-2019, 20:35
KODAK 12" F4.5 Ektars came in Kodak Ilex# 5 shutters with threads unique to Kodak Ilex shutters. Think these Kodak-Ilex shutters are mostly the same. It is the Kodak lens cell collars that are made to the needs of the lens cell set.

At some point it might worth while to measure a number (Have a few here and micrometer that would do this nicely) of Kodak Ilex# 5 shutter lens cell mounting distance to see how consistent they are.


Bernice


Could we infer from your knowledge that shutter replacement may affect lens performance if not 'zeroed' by an expert?

Tin Can
23-Feb-2019, 01:28
Bernice,

You have good logic. Cutting cell metal to adjust is wiser than boring shutters to size. Kodak was smart.

I have a couple dissimilar Ektars I use on one shutter.

Thank you



KODAK 12" F4.5 Ektars came in Kodak Ilex# 5 shutters with threads unique to Kodak Ilex shutters. Think these Kodak-Ilex shutters are mostly the same. It is the Kodak lens cell collars that are made to the needs of the lens cell set.

At some point it might worth while to measure a number (Have a few here and micrometer that would do this nicely) of Kodak Ilex# 5 shutter lens cell mounting distance to see how consistent they are.


Bernice

Bernice Loui
23-Feb-2019, 10:28
Folks who designed lenses at Kodak back in those days were far more than smart, they were wise and very practical in the optics they created.

Over the decades of using Kodak Ektar LF lenses, they have given me a very deep appreciation for their work.

Folks like Prof. Rudolf Kingslake no only had a very deep and broad understanding of optics design, they understood human visual perception in profound ways. It is one thing to design then craft a lens by math alone, these folks took the design process that many steps further by tweaking the design using visual assessment. Their production Ektar lenses were hand tweaked-adjusted individually with remarkable quality control.

Rudolf and Hilda Kingslake, both professors with no kids. They dedicated their life to educating others and optics work.

"Rudolf Kingslake was born in 1903 in England. His father was an amateur photographer and young Rudolf became curious about how the lenses on his cameras worked. He had read Photographic Lenses, A Simple Treatise by Conrad Beck and Herbert Andrews that showed sections of lenses; Rudolf wondered why some lenses required six elements and some only four. He soon learned that Imperial College (London, UK) had a department of optics where lens design was taught, so decided to follow up on what was becoming more than just idle curiosity to him."
http://spie.org/newsroom/rudolf-and-hilda-kingslake?SSO=1


The image personality of Kodak Ektars are not for all as the images they produce is not a one size fits all, it does fit some.

The tedious math required to create Kodak Ektar lenses was done by a room full of human "computers". These were gals working together on mechanical calculators to solve a much larger math problem. These were the same gals who worked on various government WW-II programs like the Manhattan Project.

At some point, due to curiosity, I'll take a few of the Kodak Ilex#5 shutters and measure them on the granite surface plate with digital height gauge and post the findings. Think it would be good for any who are interested.



:)
Bernice

-Just noticed this is post# 1000 !



Bernice,

Kodak was smart.

Thank you

Whir-Click
23-Feb-2019, 11:12
We are all deeply in Professor Kingslake’s debt. Quite apart from his role designing some of Kodak’s very best lenses, his book “A History of the Photographic Lens” gives tremendous perspective and insight. His 1974 paper "The Rochester Camera and Lens Companies" is one of the best (and only) resources for understanding the breadth, complexity, and interrelationships of the Rochester optical industry in the 19th and 20th century.