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View Full Version : G-Claron: is it as sharp as a lens optimized for infinity?



chris jordan
25-Jan-2004, 19:54
Been thinking about getting a 305 G-Claron for 8x10 use and it seems a great lens-- nice and small, big image circle, and fairly cheap. But I've read that it's optimized for 1:1 and you have to stop down to f/22 to correct for optical problems when shooting at infinity. So my question is, assuming you shoot it at f/22 or a smaller aperture, is it JUST as sharp as a lens optimized for infinity?

And, what happens if you shoot it at infinity wide open-- how bad is the image compared to a lens optimized for infinity? Would if be a bad lens to get if I'm planning to do almost all of my shooting at infinity and virtually never closer than about 50 feet?

Do people have a recommendation for a better all-around landscape lens for 8x10 in the 300mm range?

~cj

tim atherton
25-Jan-2004, 20:06
Hi Chris,

try

http://www.wisner.com/myth.htm

for some info - The Myth of the "Flat Field" Lens - lots of math and a short extract below

"Let us begin by listing a few of the common myths and wives' tales regarding "flat-field" lenses.

How many of you have been told that you shouldn't photograph three dimensional objects in the studio with such a lens? How about the admonition that flat-field lenses are not good at infinity or for landscapes? In a related subject, have you been told that in order to photograph a group of people it is necessary to place them in a semicircle so that they will all be in focus? Every one of these statements is bunk, and using a little theory, we will explain why. We will also explain how to use such a "tricky" lens.... etc

....More recently the G-Claron and Fuji AS lenses have come into use, both as long 4x5 lenses and as wide field 8x10 lenses, in both cases offering the advantage of light weight, and also with excellent results. In the case of the former lenses, there are no detectable aberrations when used at infinity even wide open. As one would expect after our discussion, the latter lenses should be stopped down two to three stops for use at infinity.

In closing, I would like to say that I object to the term "flat-field" lens. It is the fervent goal of the designer to be sure that every lens has as flat a field as possible. Therefore, we should agree to call all lenses (particularly modern lenses) "flat-field" lenses, or with the knowledge that Petzval sums and astigmatic surface corrections are a matter of degrees and not absolutes, we should agree that no lens has a flat field. I prefer to speak in terms of degrees, but even so, there should be no question that the flatter the better."

Michael Mutmansky
25-Jan-2004, 20:14
Chris,

The G Clarons that Schneider has produced since the early '90s in shutter are spaced to be optimized at infinity. I was directly told this by an engineer at Photo+Expo last fall. He said that they recognized that most of the in-shutter lenses were being used for infinity work, so the adjusted that spacing to that use.

If you want to use the lens in the field, I can think of no 'better' lens for that use. You will have to be a little more careful about flare due to the single coating, but otherwise, you will likely find no differences that a normal viewer will appreciate.

---Michael

Jim Galli
25-Jan-2004, 20:18
Or sharper! Somewhere on Tuans LF info page is an area about lenses that mentions a 305 G-Claron that was resolving 67 LP / mm. That's an awesone number for a 150 and almost unreal for a 305. My 270 and 305 G-Clarons are probably my sharpest 8X10 lenses. Love the 270 but they're harder to find. And if you get the inkling for 7X17 or 11X14 you won't have to go shopping. The 305 G-Claron will cover with movements. I had the 305 on the 7X17 in Death Valley a week ago yesterday. Haven't got the film developed yet.

Ernest Purdum
25-Jan-2004, 20:20
I suppose a comparison would have to be made against some particular lens optimized for infinity. Probably some would be better, some worse. I doubt if you would notice a difference unless under huge enlargement.



As to shooting with it wide open, maybe somebody has done it, but I'm not sure why one would, aside from curiosity or perhaps to see if it produced a desired softness. A bad lens to get for if you are planning to sshoot from fifty or more? I don't think so and I think most people that have used them would agree.



Regarding alternatives, there are many, but the light weight, good image circle, small size, ready availability and (usually) moderate price make the G-Claron an attrractive proposition.

chris jordan
25-Jan-2004, 20:42
Thanks for your thoughts guys. I must admit I'm pretty confused with all of the types of modern lenses-- some new Schneider and Rodenstock lenses in the 300mm range cost more than two thousand dollars but they are much faster with huge front elements. The only thing I care about is sharpness-- I want the best possible optics so I can make tack-sharp 700MB scans from my 8x10 originals. If an f/5.6 Apo-Ronar is sharper at f/22 than the G-Claron, I'll get it. But most of my work is done at smaller apertures so I don't need the speed of an f/5.6. Given these considerations would you still go with the G-Claron?

Michael Kadillak
25-Jan-2004, 21:19
From your other posts, I understand that you are now shooting primarily color negative film. The only concern I had before I got my G Clarons was the fact that they are single coated lenses. Until I saw results produced from the lens, I was skeptical to say the least. Now I know that this lens is as sharp as a hand full of razor blades. I know other professionals that also shoot color neg film with 1960's vintage single coated lenses that do not appear to resolve anywhere near the G Claron and they are pleased with their choice in optics and the results that they produce. The best judgement you could make would be to put the 305 on a lensboard and make a few exposures. Only then will have the hard data in front of you to inspect under your set of operating criteria (scanning, large prints, etc.).

Let us know what you end up with in your search.

Michael S. Briggs
26-Jan-2004, 00:15
Comparing a G-Claron to a Rodenstock Apo-Sironar-S (for example), the Apo-Sironar-S should give better results: it is designed for distant objects, uses extra-low dispersion glass and has multicoating. How large will the difference be at typical taking apertures for 8x10 (e.g., f22, f32)? Probably quite small. How many people really know the answer from having taken simultaneous test photos using both lenses? Probably very few.

I have used G-Clarons on 4x5 with nearby and distant results and have been pleased with the results.

A 300 mm Apo-Ronar wouldn't be an ideal choice for distant objects with the 8x10 format because it has rather narrow coverage. If you want to consider another lens beside the 305 G-Claron or a large, heavy and expensive f5.6 lens, another good possiblity is the 300 mm f8.5 Fuji-C. This lens is small, multicoated and still made, but only unofficially imported to the US. Fuji's specs give it coverage similar to the 305 G-Claron. I haven't used it but have used the 450 mm version.

jonathan smith
26-Jan-2004, 03:46
Every shot I've taken with my 270 G Claron has been very sharp, including one shot at f/22. They also seem to have a lifelike quality missing in some other lenses. Could just be luck, but might have something to do with the coatings.

phil sweeney
26-Jan-2004, 05:01
Good to know the 305 covers 7 x 17! And oddly enough there are 3 270s on ebay right now.

Arne Croell
26-Jan-2004, 06:30
At least 2 of those 270's on ebay are G-Claron WA's though. These should not be mixed up with the regular G-Clarons. The WA's are wide angle process lenses like the process Nikkors, with big bulging lens elements (double Gauss construction similar to the WF Ektars). They are also good and can be adapted to a shutter (the 270 f/11WA fits Copal 3 threads, but has a different spacing), but are much bigger and heavier.

Paul Schilliger
26-Jan-2004, 09:51
Sharp and much better coverage than a 300 Nikkor M. The 305 screws directly into a Copal #1.

Christian Olivet
27-Jan-2004, 20:59
I have two, the 210mm. which barely covers 8x10, and the 355mm. which is mounted on a barrel. Both have served me very well. I have always been impressed with the sharpness, more even so when I start getting closer to things. By the way, I am sick of using the lens cap as a shutter. Michael you said that G Clarons on shutters are optimized for distant shooting. I heard that the 355mm. I have will screw right up on a copal 3 shutter. Now I wonder if this would be a wise move. Will the distance between elements change and if it does, will it affect the performance of the lens? Any comments on that? Thanks!!

Michael Mutmansky
28-Jan-2004, 05:26
Christian,

Not sure. What you may find is that the cell spacing when in the shutter is different than the cell spacing when in the barrel. That may be all they did, but I really have no information on that.

You can try emailing Schneider to determine if converting to a shutter will pose any issues.

It is my understanding that the Schneider representative was basically telling me that the elements were spaced to perform optimally at infinity, and that it won't require stopping way down to get the lens to perform at it's best. In the case of the 305 (which is a great lens for 8x10, and also is quite excellent on 7x17), the best aperture will probably be larger than f22, maybe f16 or so.

However, the center of the field will be quite sharp even wide open, I suspect, because of the spacing being optimized for infinity.

For an 8x10 field lens, I don't think there is a better option out there, because the other choices are so much bigger (Copal #3 shutters), and heavier (f5.6 glass, for example) and really have no better coverage to speak of. I think it would be an extreme user that would run out of coverage with the G Claron on an 8x10 camera. I barely ever hit the corners when using it on the 7x17. However, as you get out towards the edges, you will have to stop down further to ensure adequate sharpness. Not an issue when contact printing, but for enlargements, you have to be concerned about diffraction.

---Michael

Jim Galli
28-Jan-2004, 06:47
Christian, I've mounted several G-Clarons from barrel to shutter for resale at auction etc. I have a machinists caliper that is accurate to 10 thousandths inch and I always check first in barrel and then in shutter. They're always dead on and I've never had to use a spacer. You will have good success mounting it in a Copal 3 yourself. Whether Schneider actually changed cell placement I don't know. It makes a good story but their literature on-line doesn't indicate it. If they did, it was by moving glass groups within the barrels, not by changing to a different barrel. This is observation only from stuff I've worked on from very early to fairly late. It would be interesting to get some actual facts from Schneider. My experience has been that G-Claron's of any age are great performers. Your 355 will cover 8X20 and I think 12X20 if you need it to.

Christian Olivet
29-Jan-2004, 19:29
I think I will go for the copal 3 shutter. I guess it will take just a few negatives to see the truth about it. My guess is that the lens will continue to shine.

Thanks