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  1. #21
    RalphLambrecht's Avatar
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    Henning

    I'll go PM from here!
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  2. #22
    Ed Sukach's Avatar
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    ??? Are we talking about LENS resolution, or FILM resolution?

    In LENS testing (at least in the old, Luddite, Optical Bench way), no film or ground glass is used: the microscope is focused on the aerial image - much the same as "Grain Focusing" in the enlarger.
    Introducing film into the testing provides the opportunity for a number of elements that will invariably degrade the results: flm flatness, emulsion/ developing charactersitics, mechanical "shake" of the support system ...

    Is it possible to see exteremly high resolution in any area of any given lens? Absolutely, but maximum resolution, by itself, is an incomplete test of the performance of a lens.
    Carpe erratum!!

    Ed Sukach, FFP.

  3. #23

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    As you say, testing lens resolution by itself is an incomplete test. So we are talking both lens and film resolution.
    Real life lens use involves both a lens and film anyway.

  4. #24

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    Quote Originally Posted by Henning Serger View Post
    Aron,

    it is difficult to write formulas here with this text format, therefore I have done the calculation for you and will try to explain it as simple as possible:

    1. Measure the lines on your test chart: Most likely there will be one black line and one white line per millimeter, and the number 1.
    And at the next pattern two black lines and two white lines on one millimeter and the number two. And so on.
    So the numbers give the linepairs per millimeter on the original test chart.
    Check whether this is the case with your test chart.

    2. Your distance test chart - film plane was 2,50 meters.

    3. Focal length of your lens 50mm.

    4. Resolution: If you can seperate the lines of number 2 on the negative, than the resolution is 96 linepairs per millimeter.

    If you can seperate the lines of number 3 on the negative, than the resolution is 144 linepairs per millimeter.
    Number 3,5: 168 lp/mm.

    Best regards,
    Henning
    Hello Aron,

    I have just seen a little mistake: Your Fuji lens has 55mm, not 50mm.

    Here are the corrected calculations:

    - Number 2: 87 lp/mm
    - Number 3: 130 lp/mm
    - Number 3,5: 152 lp/mm

    Best regards,
    Henning

  5. #25

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    Quote Originally Posted by RalphLambrecht View Post
    Henning

    I'll go PM from here!
    Ralph,

    I have send you a pm.

    Best regards,
    Henning

  6. #26

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    There are interesting things to discuss we may not know about?
    Yet we should be told that you two discuss them in private?

  7. #27

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    Quote Originally Posted by Henning Serger View Post
    Hello Ralph,

    probably the difference is because of the following reasons.

    1. ....

    2. .....

    3......

    Best regards,
    Henning
    Let me just add another relevant points:

    4. The resolution values I have described refer to our tests with the new Zeiss Makro-Planar 2/50 ZF. This lens surpassed all of my other very good prime lenses so far. Probably it is one of the best 35mm lenses on the market.

    Have a look at these data:

    http://www.zeiss.de/C12567A8003B8B6F/EmbedTitelIntern/MP_2_50ZF_DE/$File/MP_2_50ZF_DE.pdf

    http://www.photozone.de/nikon--nikko...w--test-report

    5. With BW film, developers have visible influence on resolution. Not huge, but visible. Due to our tests the best developers concerning resolution deliver about 5-10 % higher resolution values.

    6. To achieve better focus accuracy, a test chart with integrated Siemensstern is very helpful. The Siemsstern gives much better indication of focus accuracy than the line patterns.
    A viewfinder magnifier (2x loupe) is also very helpful to improve focus accuracy.

    Best regards,
    Henning

  8. #28

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    Quote Originally Posted by Ed Sukach View Post
    ??? Are we talking about LENS resolution, or FILM resolution?
    Hello Ed,

    to be precise: We are talking about system resolution. Aron tested his 55m Fuji lens in combination with Ilford Delta 100.
    I have tested the Zeiss 2/50 (and other lenses) in combination with Delta 100 (and lots of other films). And with other films, the resolution values differ, of course. In each case a more or less different system resolution dependant on the film used.

    Best regards,
    Henning

  9. #29
    Ed Sukach's Avatar
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    Quote Originally Posted by Henning Serger View Post

    to be precise: We are talking about system resolution. Aron tested his 55m Fuji lens in combination with Ilford Delta 100.
    I have tested the Zeiss 2/50 (and other lenses) in combination with Delta 100 (and lots of other films). And with other films, the resolution values differ, of course. In each case a more or less different system resolution dependant on the film used.
    The original title was "Very High Resolution LENS" , not "Camera" or "System".

    Of course, far more often than not, we will use our lenses in cameras, but I think it is a grave error to judge the value of a LENS from a test with so many potential biases possible from an entire SYSTEM ... and this is done all too frequently in photography. I am NOT trying to be anally "pecise", just clinging, hopefully, to reality.
    Carpe erratum!!

    Ed Sukach, FFP.

  10. #30

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    Quote Originally Posted by Ed Sukach View Post
    The original title was "Very High Resolution LENS" , not "Camera" or "System".

    Of course, far more often than not, we will use our lenses in cameras, but I think it is a grave error to judge the value of a LENS from a test with so many potential biases possible from an entire SYSTEM ... and this is done all too frequently in photography. I am NOT trying to be anally "pecise", just clinging, hopefully, to reality.
    Hello Ed,

    reality for us photographers in most cases is that we are using our lenses in combination with film. A lens designer will be interested in the fact that an excellent prime lens at f4 can have an aerial resolution of about 400 Lp/mm (near its diffraction limit).
    A photograper probably is not interested in this single value.
    He wants to know what will be on the film in the first step, and on the print in the second step.

    And that is what Aron is interested in: He has a lens he likes, and with Delta 100 a film he likes, and he wants to know what resolution at which aperture he can achieve with his preferred combination.
    He started a test, and he has asked us whether his results may be reasonable.
    For his photographic reality that is a question he is interested in. And there is nothing wrong with that I think.

    Best regards,
    Henning

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