lens test question

[zsolt]

Greetings Folks!
could i install my taking lens from my camera to my enlarger,and make (some sort of a)lens resolution test at its different f-stops?
just primitive way put a negative in the enlarger(enlarger setup with the taking lens) make a big enlargement,take a small crop from that, and print that in all the f-stops,and see what it has to say about "sharpest apperture"..maybe focus shift too..
does any of you here see a problem in this idea?
Thanks for your time!

[zsolt]

or the light-film-paper distance difference from the light/subject-lens-film would mess it up?

[Bob Salomon]

Won't tell you anything. Just go outside and shoot images of a brick wall on full daylight at 50' or so and use different apertures. 22 will probably be the best. Use a good tripod and a cable release.

[zsolt]

Thanks for the answer Bob!just thought to give it a try before i "waist" some film..
tripod and release i got steady as the brick wall i will photograph:)
Best!

[Jac@stafford.net]

When you put the camera on the enlarger you can find the best printing aperture by using a focusing scope.

[Ken Lee]

Outdoors, you can use a strong pair of reading glasses or a focusing loupe. No need to shoot any film. Just inspect the groundglass. If you shift the lens sufficiently off-center, you can watch the image quality change too.

[Jim Jones]

I've tested 35mm camera lenses by projecting a high resolution target through the lens onto a large flat white surface. It is quick and reveals gross defects in the lenses performance. A conventional lens test on film provides numerical data for comparison. This technique would be awkward with large format.

[fishbulb]

Unless you want to use the lens for very close images, testing it via an enlarger will only tell you how well it performs at those distances.

My normal test when I get a new lens is to go out and use it as I intend to use it. Then I check the images and see if they match my expectations based on how I took the shot.

[zsolt]

Ken Lee: i tried that Ken,with a loupe,but couldnt see a thing,but will go out today and will have another good look.
fishbulb ,guys,i tried the lens on film in action,and im not that satisfied with the results.. that is the reason i was thinking to make a test to find the best working apperture.maybe i got a lemon,and its just a bad sample from this line of lens.dont know..
we are talking about "normal" landscape situations f22 and a Nikkor M 300mm f9 lens.on a Wisner Zone VI on a a heavy aluminium Gitzo tripod with the biggest Manfrotto ball head,cable release.so the lens and film is rock solid steady..and a pain in the ass to carry around;)i made enlargements,they were around 40x50 cm,inspected with naked eye and loupe.
i got other lenses too and they perform better than the Nikkor.i will go to travel tomorrow,but if im back i will make a simple wall brick test,and see.(but first of all i will try again what Ken sad )
Thanks Everyone!

[Jac@stafford.net]

Unless you want to use the lens for very close images, testing it via an enlarger will only tell you how well it performs at those distances.

You are right, of course. I misunderstood the OP's question. I thought he was thinking of using a taking lens as an enlarging lens.
.

[Bob Salomon]

Ken Lee: i tried that Ken,with a loupe,but couldnt see a thing,but will go out today and will have another good look.
fishbulb ,guys,i tried the lens on film in action,and im not that satisfied with the results.. that is the reason i was thinking to make a test to find the best working apperture.maybe i got a lemon,and its just a bad sample from this line of lens.dont know..
we are talking about "normal" landscape situations f22 and a Nikkor M 300mm f9 lens.on a Wisner Zone VI on a a heavy aluminium Gitzo tripod with the biggest Manfrotto ball head,cable release.so the lens and film is rock solid steady..and a pain in the ass to carry around;)i made enlargements,they were around 40x50 cm,inspected with naked eye and loupe.
i got other lenses too and they perform better than the Nikkor.i will go to travel tomorrow,but if im back i will make a simple wall brick test,and see.(but first of all i will try again what Ken sad )
Thanks Everyone!
If you were not satisfied with the results on film, and were shooting within the optimal range and aperture of the lens then you have already tested your lens and it failed. Get a better lens. And while you are at it check the parallism of your camera.

[Peter De Smidt]

And whether the film plane of your holder is at the proper depth.

[Ken Lee]

Ken Lee: i tried that Ken,with a loupe,but couldnt see a thing,but will go out today and will have another good look.

As Bob suggested, focus on a subject with discrete lines and edges (like a brick wall). Make sure the light is clear and "scraping": late afternoon on a cloudless day is good. Look through the loupe and slowly stop-down the lens. You will see sharpness gradually increase until you reach the optimum aperture, then start to decline as you exceed it.

With some lenses that exhibit focus-shift when stopped-down, you will be able to detect the need to refocus.

[Mark Sawyer]

Thanks for the answer Bob!just thought to give it a try before i "waist" some film...

I'd shoot paper negatives; they'd tell you all you need to know...