Testing 35mm lenses on APS camera?

runswithsizzers

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When evaluating used 35mm SLR camera lenses, is it valid/wise/practical to test the image quality on a crop sensor camera when the intended use of the lens is on a film camera?

Is it possible that some defect - like decentering - which is usually seen more at the edge of the frame - might not be noticeable on the crop sensor camera, but might be noticeable on the full frame negative?

The reason I ask is, some eBay sellers have a 14 day return policy. For me, it would be a tight schedule to shoot a test roll and get it processed within the return period. I realize that some mechanics like stopping down from full aperture viewing must still be tested on the film camera, but that can usually be done without film in the camera.

* I mention the crop sensor camera only as a tool for testing analog lenses, and not as part of my analog work flow. I hope this is acceptable in the analog section(?)
Thank you
 

MattKing

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You would only be testing the centre of the imaging - problems like mechanical vignetting wouldn't be revealed.
Some aberrations are also more pronounced near the edge of the frame.
It would also be difficult to detect barrel or pincushion distortion.
 
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runswithsizzers

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Thanks for your reply. I should explain, I am not wanting to do serious testing to evaluate the design/manufacture of the lens. Design limitations like vignetting, barrel/pincusion, and abberations, are usually known issues, as these older lenses have been around long enough to have a reputation. My testing is only for the purpose of discovering if a particular lens is decentered, or otherwise damaged.

Paul Howell said:
With a 14 day return policy why not shoot a roll of film?
Click to expand...
If the lens shows a problem on the digicam - it might save me the price of film and chemicals, and a couple of hours work.

But if the digicam check does not show any significant defects, then maybe I should shoot a test roll(?) That is what I am trying to decide.
 

MattKing

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Actually, I think the problems I listed can arise from damage or something like improper re-assembly, and thus the concern.
 

benveniste

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I assume you are thinking of testing using an APS-C digital camera rather than something like, say, a Nikon Pronea.

Using an APS-C camera can tell you about center sharpness, and some idea of distortion and decentering. It can't tell you anything about light falloff. If you think you know enough about the design of the lens to extrapolate from what's there, cool. But personally? I'd shoot a test roll.
 

reddesert

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If you can develop a short roll of B&W at home, then it doesn't take too long to take and develop a few test shots. It's more of a PITA if you have to send the film out.

However, assuming we are talking about an APS-C digital camera with a crop factor of 1.5x, then the digital sensor reaches 2/3 of the image height of full frame 35mm. That should be enough to detect some major problems, like a lens assembled wrong or out of alignment that has excessive spherical aberration and coma. (I don't know how people keep getting lens elements in backwards, but it has been posted about a couple of times recently, although I think it was in the medium format forum). You wouldn't learn about vignetting or distortion at the very corners, but some of that you can probably see on the ground glass in an SLR.
 

Paul Howell

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Question I should have asked, what system, what lens? Reason I ask if you are shooting Nikon, Canon, Minolta, Pentax late model AF, I don't see much of chance that you will get a bad lens, and there are lots sites that rate individual lens. If their are issues with a lens that had been dropped or miss repaired a cropped sensor D body should let you if you have trouble in River City. If you are shooting older MF lens, per 70s, then there was some issues with design from lens to lens and shooting a roll makes sense. When I was was shooting Nikon F then F2, and 3 I upgraded my lens AI set to AIS, but I dropped my older AI 28mm and replaced it with a AIS 28mm. In those days I tested my lens, and the new out of the box was off, I took the test shots to the store I bought from and the next new out of the box was spot on. That was a late 70s lens, lens that are even older, it would good to test with film, or buy a first generation full frame body.
 

flavio81

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runswithsizzers said:
When evaluating used 35mm SLR camera lenses, is it valid/wise/practical to test the image quality on a crop sensor camera when the intended use of the lens is on a film camera?
Click to expand...

In my opinion, no. Definitlely not. Great full-frame lenses might test as mediocre om APS cameras. Or, mediocre full-frame lenses can test great on APS cameras by virtue of great central definition (!)
 

reddesert

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When talking about lens testing, it's important to decide several things:
- what is the goal of the test?
- what is the measurement method?
- is the measurement capable of translating into real-world results, to meet the goal?
I was trying to make these points in the "medium format lens tests" thread but I got tired of the arguments, although perhaps I should post this three point summary in it.

Anyway, it's my impression that the OP's goal is to determine "is this lens in optical condition to perform as originally intended?", and not to decide is lens A better than lens B or whatever. The assessment of condition is hopefully easier to reach, because most of the things that would damage a used lens should show up in the central 2/3 of the field as well as on the full frame.
 
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runswithsizzers

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@Paul Howell, At present, I have been shopping for a Konica Hexanon AR lens in the 35mm-40mm range to be used on a Konica Autoreflex T4. So far I have bought two copies of the 40mm f/1.8 Hexanon AR lens and both had issues. The first one had significant haze and a small patch of fungus. Of course, I did not need a test photo (digital or otherwise) to see that, only a bright light.

The second 40/1.8 lens I bought looked pretty good upon visual inspection, and it passed the flashlight test. I already had an adapter to mount a Hexanon lens on my Fuji APS-C digital camera, so I took a few test shots - and they were blurry. I don't mean slightly soft, but seriously blurry. The center of this second lens at f/5.6 was significantly softer than the corners of the first (hazy) lens at f/1.8. Fortunately, that eBay seller allowed returns, so I'll get a refund except for return postage.
 
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Paul Howell

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By now you may have already sent the lens back, but, how did it look though the T4, and how does your 50 1.7 look with the adaptor on your Fuji? I would have thought a lens that was really out of focus would show when viewing?
 
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runswithsizzers

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Paul Howell said:
By now you may have already sent the lens back, but, how did it look though the T4, and how does your 50 1.7 look with the adaptor on your Fuji? I would have thought a lens that was really out of focus would show when viewing?
Click to expand...
I tested the 40mm on the Fuji first, and after seeing the results, I knew I was going to send it back, so I never even mounted it on the Konica T4. I did not notice the image as out-of-focus when viewing through the Fuji's viewfinder. Probably because: a. the fine detail in my test scene was somewhat far away and smallish in the viewfinder, b. the Fuji electronic viewfinder is above average compared to other digital cameras, but is pitifully small and dim compared to a proper SLR pentaprism viewfinder, and, c. some bright clouds were causing glare on my eyeglasses. Now, I do wish I had checked the view of the 40mm through the T4 viewfinder.

The Hexanon 50/1.7 looks pretty good on the Fuji with an adaptor, I think. You can see some results <here> I was impressed with not only the sharpness of the 50/1.7 but also the color rendition.

Thanks to a generous donation by a kind Photrio member, I have another copy of the 40mm f1.8 Hexanon AR on its way to me - and, I think I will buy a 35mm f/2.8 as well. I am looking forwards to shooting the Konica T4, and it will be interesting to compare results to my Pentax MX and Pentax lenses.
 

Paul Howell

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I've have Pentax, M42 and K, dating back to 1966, then Konica, followed by Nikon, then Sigma SA, then Minolta A, Minolta MC/D and bunch of all ran cameras and lens for fun, Petri, Topcon, Kowa, Argus, Chinon, Cosina, Yashica. Off all the lens I owned or own and tested Konica rates as the best from lens to lens, I don't know of a bad Konica lens. The Konica Hextar M lens are very collectable. Too bad the later model AR bodies have only so so build quality. I traded in my T with my set of lens including a 57 1.2, one of the few lens I really do miss for a Nikon F and motor drive. The 1.2 was not as sharp as the 1.7 or 1.4 stopped down, but wide open, do miss it, but not enough to get another one. I'm out of hearing aid batteries, next time at the supermarket will pick some up so I can shoot a few rolls with my current T3 and 4.
 

Alan Edward Klein

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Paul Howell

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Tempe Camera no longer offers E6, I think Photo Forum will send out, Phoenix Photo Lab, develop and scan C41 and black and white, no E6, Wilson Camera is now processing E6, don't know what their turn around time is, and I don't think OP lives in Arizona let alone Scottsdale. But for those living the Metro Area, Tempe Camera is now processing C41 5 days a week with a one day turn around.
 
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