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  1. #11

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    Quote Originally Posted by Aron View Post
    For the test I was using the ISO 12233 test chart as it is easier for me to work with it than the USAF 1951 chart.

    On the test chart the width of the lines simply are constantly getting lower and I take the value (1-2-3-4 in my case as the distance between the camera and the chart was fairly high (2.5-2.8m) to minimize the my printer's resolution limit (1200 dpi) and that of the film causing trouble) where I still can count all of the lines (5 black and 4 white), then I multiply this number with 100 and devide it by the height of the test chart on my negative. No need for camera-test chart distance measurments and this way I think it is also more accurate.

    Aron
    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

  2. #12
    lxdude's Avatar
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    I'd just like to add to comments on the lens.
    My first good camera and lens in 1974 were the ST801 with the 55/1.8. It's all I used for about 3 years, including with extension tubes and/or reversed. To this day that lens' results hold up to anything I've used from the other makers. The other EBC lenses I've had (no zooms) have all been sweet performers. Color, contrast, sharpness, all great. Focus and aperture still smooth and reliable. Something I've noticed is, after all this time, they all have very little dust inside.
    So whether your numbers are accurate or not, expect great results from that lens.

  3. #13
    RalphLambrecht's Avatar
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    I'm not questioning your experience, but why is it, you think, that I have never measured a resolution that high. Not with a Mamiya lens, a Hasselblad lens or any other lens. I get 65 lp/mm with Hasselblad and up to 90 p/mm with Mamiya lenses. My test targets have a higher contrast than yours, and still, nowhere close to your numbers. I don't use high-acutance developers (D76 1+1) but the same films you mentioned. Are we counting differently?
    Regards

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

  4. #14
    RalphLambrecht's Avatar
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    Quote Originally Posted by Henning Serger View Post
    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.

    Best regards,
    Henning
    Henning

    With this you mean that each line is 0.5 mm wide, correct?
    Regards

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

  5. #15
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    Quote Originally Posted by lxdude View Post
    I'd just like to add to comments on the lens.
    My first good camera and lens in 1974 were the ST801 with the 55/1.8. It's all I used for about 3 years, including with extension tubes and/or reversed. To this day that lens' results hold up to anything I've used from the other makers. The other EBC lenses I've had (no zooms) have all been sweet performers. Color, contrast, sharpness, all great. Focus and aperture still smooth and reliable. Something I've noticed is, after all this time, they all have very little dust inside.
    So whether your numbers are accurate or not, expect great results from that lens.
    I just read this thread and coincidentally I had just printed a negative from my archive for a friend. The negative was from 1974 and my camera at the time was a ST701 with the EBC 55/1.8. I remember commenting to myself when printing the negative that it was very sharp. Seem like I have come full circle because the ST701 is long gone but my favorite Large Format lenses are Fujinons.

  6. #16

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    Quote Originally Posted by RalphLambrecht View Post
    I'm not questioning your experience, but why is it, you think, that I have never measured a resolution that high. Not with a Mamiya lens, a Hasselblad lens or any other lens. I get 65 lp/mm with Hasselblad and up to 90 p/mm with Mamiya lenses. My test targets have a higher contrast than yours, and still, nowhere close to your numbers. I don't use high-acutance developers (D76 1+1) but the same films you mentioned. Are we counting differently?
    Hello Ralph,

    probably the difference is because of the following reasons.

    1. In general medium format lenses have a bit lower resolution values than lenses for 35mm (yes, there are some exceptions from this rule). The bigger the lens diameter, the more difficult it is for the optic designer to design a lens.

    You may have a look at these medium format lens tests:

    http://www.hevanet.com/cperez/MF_testing.html

    These tests were made with TMX. Just have a look whether you find the lenses you have tested.
    But there you find some Zeiss and Mamiya lenses with resolution values of 100 lp/mm - 120 lp/mm in combination with TMX (system resolution).

    LF lenses: http://www.hevanet.com/cperez/testing.html

    2. If we photograph a test chart in a distance of 2 or 3 meters, absolutely exact focussing is necessary to achieve more than 100 lp/mm resolution. The focus must be exactly down on the millimeter.

    The problem with focusing is, that we don't have really exact focusing systems. Neither our manuel focusing systems (split image, matte screen, microprism) nor the AF systems deliver the precision we need to exploit the capabilities of our lenses and films.

    Therefore we have to do a simple, but effective trick: "Focus bracketing". Shooting several frames, each frame newly focused with a sligtly different focus. We make a series and choose the pictures were the focus is dead on.

    When I do my lens and film tests, e.g. with TMX, then always some negatives have resolution values of only 80 or 90 lp/mm. Because the focus is a bit in front of or behind the flat test chart.
    But some shots of the test series are absolutely precise in focus, because of the "focus bracketing".

    And with focus bracketing you can also avoid another problem with lens resolution tests: Focus shift when stopping down. A lot of lenses have this characteristic (have a look at Dr. Nasses report about the lens MTF tests I have mentioned in my first post).

    3. To exploit the full resolving power of our lenses and films we have to avoid camera shake completely. That means very stable tripod ( I am using a Berlebach Report 3032) and MLU and short shutter speeds (1/250 or even shorter).
    Vibrations make a big difference in resolution. I have compared my F90X with my F6. Even at 1/250 on the Berlebach tripod I get much higher resolution with the F6, because mirror and shutter are much better damped and have less vibration (even with the MLU not activated). And with MLU the difference is much more significant of course.

    My English ist not the best, I hope my explanations were helpful for you. Your German is much better than my English , so if you are interested in further information, let us continue per pm. And Leverkusen is not so far from me, if you want to see my test pictures, than it is no problem at all to show you.

    Best regards,
    Henning

  7. #17

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    Quote Originally Posted by RalphLambrecht View Post
    Henning

    With this you mean that each line is 0.5 mm wide, correct?
    Yes, correct. One millimeter with one 0,5mm black line and one 0,5mm white line
    = one linepair.

    Best regards,
    Henning

  8. #18
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    Henning,
    I will not be able to continue testing for a week, but i'll continue after using your advices.
    I'm just getting even more interested on the topic with the help of the already many helpful posts. Can you recomend me some articles where I can find more info on the topic of lens resolution and how different lens designs can affect it?

    Aron

  9. #19

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    Quote Originally Posted by Aron View Post
    Henning,
    I will not be able to continue testing for a week, but i'll continue after using your advices.
    I'm just getting even more interested on the topic with the help of the already many helpful posts. Can you recomend me some articles where I can find more info on the topic of lens resolution and how different lens designs can affect it?

    Aron
    Hello Aron,

    at first step you probably find some interesting information in the Zeiss camera lens news number 17, 19, 20, 24 (resolution), and 30, 31 (reports of Dr. Nasse concerning lens design and MTF). I think that is enough to read for the beginning .

    Best regards,
    Henning

  10. #20
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    Quote Originally Posted by Henning Serger View Post
    Hello Aron,

    at first step you probably find some interesting information in the Zeiss camera lens news number 17, 19, 20, 24 (resolution), and 30, 31 (reports of Dr. Nasse concerning lens design and MTF). I think that is enough to read for the beginning .
    Henning, my mistake, you already recommended these articles in your first post. Maybe also my eyes are needed to be checked.

    Aron
    Last edited by Aron; 09-10-2009 at 11:45 PM. Click to view previous post history.

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