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Thread: Determining Film Resolution

  1. #21

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    Re: Determining Film Resolution

    Thanks for the citation, do read the piece again.

    It says that resolutions in the table you presented are theoretical and can't be attained by real lenses. Also that the best color films can resolve 140 lp/mm and that some Zeiss lenses deliver that resolution on these films at f/5.6 and f/8.

    And it says "Objects of 4 millimeter in size (approximately 1/6 of an inch) have been imaged from almost 400 meters distance (more than 1.000 feet) with a 100 mm Carl Zeiss Makro-Planar lens at f/5.6 and a Contax RTS III 35 mm SLR camera featuring the
    unique Contax vacuum pressure plate." I'm sorry, but this isn't at all the same as separating two objects 4 mm apart 400 m away. Resolution is about separating objects, not about imaging a single object.

    Please think more about what resolution means and why we measure it in lp/mm or cycles/mm. If you want to be astronomical, think about the difference between capturing an image of a single star and seeing two stars as two stars and not a single blob of light.

    If you want to see a newer, grander claim that still doesn't attain the levels you gave, see http://www.zeiss.de/C12567A8003B58B9...256CED0054968D . Camera Lens News #24.

  2. #22

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    Re: Determining Film Resolution

    Well without getting into splitting hairs, it did say ektar 200 lp/mm and I take the point that resolution is not the same as a single object. But getting back to the original point, and as I said, you can expect only 70 lp/mm or less on 4x5 film at f22. i.e. far less than people such as myself thought until I started doing some reading.
    And that is why resolution is important. If you want fine detail in a print then you better pay attention to resolution.

    Now I better get myself one of those 400 lp/mm lenses...

  3. #23

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    Re: Determining Film Resolution

    Nope, if you want fine detail in a large print you need to start from a large negative. If the goal is 8 lp/mm in the print -- some people here claim 5 lp/mm is good enough; I suspect their visual acuity is going -- then resolution on film has to be somewhat greater than 8 * enlargement. Practically speaking, the results of enlarging film more than 10 times won't bear close scrutiny. Same goes for the sensors in digital cameras.

    Do you remember the hoopla about H&W Control Film (another way of spelling Agfa Copex) and H&W Control Developer (another POTA developer, I think)? The leicanuts who went really gaga over Control film/developer shot hand-held, thereby pissing away all of its possible advantages.

    400 lp/mm lenses? Not that cover very much. I have a useless little 100/2.8 Era-7 that Russian sources claim will beat 400 lp/mm wide open with monochromatic light. It covers rather less than nominal 6x6. My neighbor C. Barringer has a heap of Zeiss Oberkochen stepper lenses that will beat 400. Tiny coverage, short back focus, huge and heavy. He has a stack of them, nicely boxed, whose job is to keep his garage's back wall from falling over.

    If you want good big prints, move up in format and improve your technique. Or stay where you are and improve your technique.

    Or wake up and realize that a strong image will usually please even though not as sharp as you'd like.

  4. #24
    Cooke, Heliar, Petzval...yeah
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    Re: Determining Film Resolution

    IMHO I believe it could be important to know what your equipment is capable to achieve with respect to best resolution, however it's not important to achieve highest resolution with each photograph you're taking.
    Last edited by SAShruby; 12-Jun-2009 at 16:00. Reason: Slight edit...
    Peter Hruby
    www.peterhruby.ca

  5. #25

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    Re: Determining Film Resolution

    Fred Picker used to say that a good exercise is to make and print the same picture with 35mm, 4x5 and 8x10 at the same size and compare them. Now there's a practical exercise to actually see what resolution and grain are doing for or against you. I've done it, making 8x10 prints b'cuz I can't enlarge 8x10.

    Interesting results, and no, I won't tell.
    Bruce Barlow
    author of "Finely Focused" and "Exercises in Photographic Composition"
    www.brucewbarlow.com

  6. #26

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    Re: Determining Film Resolution

    Quote Originally Posted by Bruce Barlow View Post
    Fred Picker used to say that a good exercise is to make and print the same picture with 35mm, 4x5 and 8x10 at the same size and compare them. Now there's a practical exercise to actually see what resolution and grain are doing for or against you. I've done it, making 8x10 prints b'cuz I can't enlarge 8x10.

    Interesting results, and no, I won't tell.
    I think Charles Cramer does this in some of his workshops. I haven't attended any but I've read about them. I'm not sure why you're reluctant to give away the results, they're not surprising if what I've read is correct. The bigger the negative the better the results (technically that is).
    Brian Ellis
    Before you criticize someone, walk a mile in their shoes. That way when you do criticize them you'll be
    a mile away and you'll have their shoes.

  7. #27

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    Re: Determining Film Resolution

    Quote Originally Posted by Brian Ellis View Post
    I think Charles Cramer does this in some of his workshops. I haven't attended any but I've read about them. I'm not sure why you're reluctant to give away the results, they're not surprising if what I've read is correct. The bigger the negative the better the results (technically that is).
    I'm reluctant because:

    1. People should actually do this for themselves, unless they're afraid of actually learning something. They might even learn things unrelated to the actual exercise.

    2. It's clear to me that you haven't done it, based on your speculation about the results.

    Let's not be lazy now, folks. (My, am I grumpy these days!)
    Bruce Barlow
    author of "Finely Focused" and "Exercises in Photographic Composition"
    www.brucewbarlow.com

  8. #28

    Re: Determining Film Resolution

    Quote Originally Posted by Bruce Barlow View Post
    Fred Picker used to say that a good exercise is to make and print the same picture with 35mm, 4x5 and 8x10 at the same size and compare them. Now there's a practical exercise to actually see what resolution and grain are doing for or against you. I've done it, making 8x10 prints b'cuz I can't enlarge 8x10.

    Interesting results, and no, I won't tell.
    He would also tell you to photograph a white building with pealing paint as part of the test.
    Richard T Ritter
    www.lg4mat.net

  9. #29

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    Re: Determining Film Resolution

    Quote Originally Posted by Bruce Barlow View Post
    I'm reluctant because:

    1. People should actually do this for themselves, unless they're afraid of actually learning something. They might even learn things unrelated to the actual exercise.

    2. It's clear to me that you haven't done it, based on your speculation about the results.

    Let's not be lazy now, folks. (My, am I grumpy these days!)
    No, I haven't done it. I thought it was clear that I based my statement on something I read about demonstrations done in Charles Cramer's workshop, which I said I hadn't attended.

    I don't think most of us here are afraid of learning something, nor are most of us lazy. Unfortunately I no longer have a 35mm camera or a medium format camera or an 8x10 camera so I'm unable to do the testing myself. Others here are probably in a similar situation. I'd certainly be interested in knowing the results of your testing, especially if I'm wrong in what I thought I remembered reading from Charles Cramer's workshop. I imagine others would also be interested. But if you want to keep the results of your testing a secret that's certainly your right.
    Brian Ellis
    Before you criticize someone, walk a mile in their shoes. That way when you do criticize them you'll be
    a mile away and you'll have their shoes.

  10. #30

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    Re: Determining Film Resolution

    Quote Originally Posted by Dan Fromm View Post
    Thanks for the citation, do read the piece again.

    It says that resolutions in the table you presented are theoretical and can't be attained by real lenses. Also that the best color films can resolve 140 lp/mm and that some Zeiss lenses deliver that resolution on these films at f/5.6 and f/8.

    And it says "Objects of 4 millimeter in size (approximately 1/6 of an inch) have been imaged from almost 400 meters distance (more than 1.000 feet) with a 100 mm Carl Zeiss Makro-Planar lens at f/5.6 and a Contax RTS III 35 mm SLR camera featuring the
    unique Contax vacuum pressure plate." I'm sorry, but this isn't at all the same as separating two objects 4 mm apart 400 m away. Resolution is about separating objects, not about imaging a single object.

    Please think more about what resolution means and why we measure it in lp/mm or cycles/mm. If you want to be astronomical, think about the difference between capturing an image of a single star and seeing two stars as two stars and not a single blob of light.

    If you want to see a newer, grander claim that still doesn't attain the levels you gave, see http://www.zeiss.de/C12567A8003B58B9...256CED0054968D . Camera Lens News #24.
    140 lp/mm?

    That's 1000:1 contrast ratio, the best colour gets 80 at 6:1 contrast, and there's also much much higher than 140 for 1000:1 in colour, such as the discontinued Royal Gold 25 which is astounding, or Provia and Velvia which go 160.

    A lens which reaches or nearly reaches the resolution of the film or sensor means that the resolution of that lens at that f-stop is in fact much much higher than the film/sensor.

    As kodak states (and there is formula for) if you want to achieve the full resolution of a system (either the full lens or full film resolution) then the other must be 3x higher, given the uniform nature of a bayer sensor and the random nature of film grain and grain sizes I dont think it'd be quite 3x for digital, but it'd still apply in some way.

    Such high resolution lenses are also not unheard of, the Canon 70-200 f/4L IS (definately neither of the 2.8's nor the non-IS) and the Nikkor 24-70mm f/2.8 come to mind, as does the Canon G10 (at least on the wide end) which achieves it's full resolution of a staggering ~1.7 micron (sensor density) under optimum conditions - just so we're clear that would be a 114 megapixel sensor in Canon APS-C format, and 292 megapixel in 35mm format, if such a large size of such a fine process could actually be cut with any kind of yield at all and not all thrown away.

    There are ridiculously high resolution films too - including one which measures up to that level and even surpasses it - Adox CMS 20, of course every step has to be optimal.

    Again, its the right tool for the right job, there are many subjects wihch only require a small resolution - such as silhouettes against a sunset background, though of course that may benefit from granularity of larger formats which lend more effective resolution due to imaging area size, and can have smaller steps between each tone change as a side effect too.

    Though there are obviously many applications where high resolution is the right tool too.

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