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05-23-2016, 11:34 AM   #46
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QuoteOriginally posted by HoustonBob Quote
Is this a fair test? Or do the rest of you have problems with it?
Again, I don't see the rational of doing this. Did you click through on the links I provided? Did you read the second half where methods and results are discussed? The issue is not whether film can resolve, but whether the lens can resolve. The answer is yes. The lenses that made 100+ lp/mm on the test were all commonly sold as kit and are fairly representative of the better lenses of the time.

Since it is lenses you want to test, I suggest:

PDML Lens Testing Procedure

Edit: -- or --

http://bobatkins.com/photography/technical/lens_sharpness.html

...with these modifications:
  • I would strongly suggest other than color film. After all, I don't believe any manufacturer claims better that 50 lp/mm at 50% contrast for any color material. After all, we are testing lenses, not films. I suggest TMax 100 as representative of a modern emulsion. It is rated to ~130 lp/mm at 50% contrast by Kodak.
  • Best of ten focus attempts at each of your chosen apertures*
  • If possible, don't use the MZS. Use a camera with split image focus screen. If you don't have a body with that feature, limit your focus attempts on the K-1 to the optical viewfinder to level the playing field. The optical viewfinders on both cameras are equivalent in regards to focus sensitivity.
  • Don't use the focus confirm on either camera (PDAF on the MZS has focus sensitivity of about f/5.6 vs. f/2.8 on the K-1)
  • No pixel shift
  • Repeat the test using your best "modern made-for-digital" lens
Again, I don't see the rational. If you want to support your claim of inferior design for FA-series and older, it should be enough to test old against new on your K-1 using magnified live view. Whether film can capture same is irrelevant to your initial claims; unless, of course, you merely want to prove your critics on this thread wrong on a point-by-point basis. If so, I wish you the best of luck** and deep pockets. Drum scans at 8000 dpi are expensive (~$50 USD per frame).

Why I stated that doing a head-to-head test is "not worth the effort" may be summed up by the conclusions of the staff at Modern Photography in 1978 (see links in comment above):

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Steve

* The big challenge to doing resolution testing is attaining accurate focus. Depth of field is no help here. (Magnification defeats DOF.) That is why multiple focus attempts and/or focus bracketing are essential when doing lens tests.
** Folk on online forums can be amazingly tenacious. Strangely, they also lose interest quickly and drift away.


Last edited by stevebrot; 05-23-2016 at 12:09 PM.
05-23-2016, 12:14 PM   #47
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@HoustonBob FA50/1.4 is a good lens choice for your experiment given its known 97 lp/mm resolution on TMAX 100 in the center from f/5.6 - f/11. Of course, you would want to test several examples to control for sample variation, using standard resolution targets, under tightly-controlled studio lighting conditions. A lens bench would actually be better.

Though imperfect, here is a link to the methodology Yoshihiko Takinami used when testing the various lenses twenty or so years ago. It was a modification to the accepted PDML test procedure created by the best users and thinkers of the time in the Pentax global community.

Last edited by monochrome; 05-23-2016 at 12:20 PM.
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