Page 4 of 5 FirstFirst ... 2345 LastLast
Results 31 to 40 of 47

Thread: My LF-prints less crisp compared to my MF

  1. #31

    Join Date
    Jan 2017
    Posts
    6

    Re: My LF-prints less crisp compared to my MF

    Sorry for my silence; been too busy the latest couple of days.

    Just to clarify. I did a test to verify that the GG vs film-plane distance is ok. For that purpose I built a test-rig, see below

    Click image for larger version. 

Name:	target_full_800px.jpg 
Views:	21 
Size:	39.5 KB 
ID:	183242

    I used a piece of sheet aluminium onto which I glued a high-contrast target. There is also a "ruler" that is slanted by 45 degrees in the z-direction (= optical axis). The zero mark on the ruler is aligned with the aluminum plate (not very clear in this image, but they are). I set-up my camera an focused on the plate/zero mark, using a very sturdy tripod and a focusing loupe (and of course the GG+fresenel combo (Wista original by the way)). After exposure, I verified that the focus was still spot on. Attached below is a close up on the resulting sheet-film negative.

    Click image for larger version. 

Name:	target_crop_800px.jpg 
Views:	28 
Size:	50.6 KB 
ID:	183243

    It is a quite lousy scan, but as far as I can tell, the focus is pretty spot on, right? I don't think I have a problem with GG alignment!

    Next-up to test is my enlarger setup...


    By the way, how to verify that the taking lens of the camera is properly assembled in terms of disance between front- and back- module?

  2. #32

    Join Date
    Jul 2016
    Posts
    4,566

    Re: My LF-prints less crisp compared to my MF

    Quote Originally Posted by henpe View Post
    By the way, how to verify that the taking lens of the camera is properly assembled in terms of disance between front- and back- module?
    You can print a USAF 1951 resolution target (http://www.takinami.com/yoshihiko/ph..._test/USAF.pdf) and evaluate the optical performance of your glass. Your lenses (Schneider Symmar-S 135 / Fujinon SW 90 / Fujinon NWS 210) should yield around 50 to 70 Lp/mm, with comparable results like here: http://www.hevanet.com/cperez/testing.html

  3. #33

    Join Date
    Jan 2017
    Posts
    6

    Re: My LF-prints less crisp compared to my MF

    A short follow-up.

    I have not tested my taking lenses yet, but I did run a few tests on my enlargers and found some interesting results.
    I was able to acquire a transparency USAF 1951 resolution target. I put the target in both of my enlargers and made prints with both my Nikon 80mm and my Schneider Componon-S 150mm. In all tests, I printed the target to x5 times magnification. When inspecting the prints with a loupe, I found that prints made with my Durst L1200+CLS450 are less sharp compared to prints made on the LPL. This is down to the very fine details of the resolution target. When looking with my naked eye, I cannot spot a difference. I suspect the difference is due to the fact that the LPL is fan-less, while the Durst is not....

  4. #34
    Jac@stafford.net's Avatar
    Join Date
    Dec 2012
    Location
    Winona, Minnesota
    Posts
    5,413

    Re: My LF-prints less crisp compared to my MF

    Quick question - do you examine the image on the base board (with sample of paper bemeath) using a grain focus device, and if you do, what brand/model number of the device? Thank you.

  5. #35

    Join Date
    Jan 2017
    Posts
    6

    Re: My LF-prints less crisp compared to my MF

    I made prints on RC paper and then inspected the prints using my eye, but also with a x40 stereo-loupe. When focusing the enlargers, I used both my Peak and my Bestwell Optics Micro-Sight (they both agree with each other, it turned out). I must admit though that obtaining critical focus was a bit tricky.

    Next time in my darkroom, I will make new test prints with the Durst but with the fan temporarily disconnected and see if there is a difference....

  6. #36

    Join Date
    Jul 2016
    Posts
    4,566

    Re: My LF-prints less crisp compared to my MF

    Quote Originally Posted by henpe View Post
    I made prints on RC paper and then inspected the prints using my eye, but also with a x40 stereo-loupe.
    To evaluate ultimate resolving power you have to ensure paper flatness. You can place a piece of glass on the easel sprayed with 3M Re Mount glue, this should ensure paper flatness. To test the corners you also have to ensure a perfect alignment, and/or focusing again for the corner.

  7. #37

    Join Date
    May 2015
    Location
    SooooCal/LA USA
    Posts
    2,802

    Re: My LF-prints less crisp compared to my MF

    There's other factors to examine too, like if the film is popping in the neg carrier during exposure, as mentioned paper flatness, easel or other movement issues, is your grain magnifier really right on, etc... Or maybe something about you like not wearing your glasses with your magnifier setting, or not seeing the grain clearly, as it is different looking from smaller formats... And really go over your enlarger settings if something is not set right...

    I have also seen on some enlargers when the bellows are extended that they create a pull that changes the focus settings sooner or later, or other locks that drift...

    Test, test, test...

    Good luck!!!

    Steve K

  8. #38

    Join Date
    Jun 2015
    Location
    Glasgow
    Posts
    1,009

    Re: My LF-prints less crisp compared to my MF

    Quote Originally Posted by henpe View Post
    I made prints on RC paper and then inspected the prints using my eye, but also with a x40 stereo-loupe. When focusing the enlargers, I used both my Peak and my Bestwell Optics Micro-Sight (they both agree with each other, it turned out). I must admit though that obtaining critical focus was a bit tricky.

    Next time in my darkroom, I will make new test prints with the Durst but with the fan temporarily disconnected and see if there is a difference....
    The Durst column should really be braced to a solid wall, otherwise you've got a big inverted pendulum wobbling around. May make a significant difference in sharpness, more than any lens.

  9. #39
    Jac@stafford.net's Avatar
    Join Date
    Dec 2012
    Location
    Winona, Minnesota
    Posts
    5,413

    Re: My LF-prints less crisp compared to my MF

    Quote Originally Posted by henpe View Post
    I made prints on RC paper and then inspected the prints using my eye, but also with a x40 stereo-loupe. When focusing the enlargers, I used both my Peak and my Bestwell Optics Micro-Sight (they both agree with each other, it turned out). I must admit though that obtaining critical focus was a bit tricky.
    Did you or not place a piece of enlarging paper under your Peak?
    After using a focusing device properly do you change aperture? (Do not do that)
    Finally, just how accurate is your stereo-loupe?

  10. #40

    Join Date
    Jul 2008
    Posts
    3,901

    Re: My LF-prints less crisp compared to my MF

    Enlarger check list:

    *Absolute alignment between enlarge head to base board. This is a must and cannot deviated by more than fractions of a mm over the entire travel distance of enlarger head to base board. The planes between enlarger head film holder to base board must be absolutely parallel at all times.

    *Enlarger stability. The table supporting this enlarger absolutely rigid and stable? The enlarger column properly supported? Much the same as a flimsy tripod trying to support a view camera vibrations and more is easily transmitted to the optical printing system causing out of focus or appearance of problem like this. This is also why the preference to a floor standing enlarger, the entire enlarger-projection system tends to moves together as a unit which helps negate some of the potential vibration problems.

    *Flatness of paper holding easel. If the easel holding the paper to be projected on is not flat some areas will be out of focus.

    *Longer enlarging times can help reduce the effects of vibration. This is much the same technique used by the microscope photographer folks. By allowing the projected image information to integrate over time on the projected media, it can help negate some of the vibration problems. Consider using a print time of 20 to 40 seconds.

    *Wrong condenser set for a given enlarger lens focal length if a condenser enlarger is used. This can result in light fall off at the edges of the print to poor optical performance of the light source to projected image to the print. The light source must be properly aligned to the condenser systems and enlarger lens. If a diffusion enlarger is used, this does not matter. Based on experience with both condenser and diffusion enlargers, the condenser enlargers when properly set up with the very best enlarging lens can project more optical information on to the printing paper that can be resolved-presented in the finished print.

    *Projecting the image to print paper using the near optimal aperture of the enlarging lens. Typical good printing aperture of an enlarging lens is two stops down from full aperture. Avoid stopping down the aperture any more than needed beyond two stops from full aperture. There is no need and will only degrade the projected image. Better to adjust the exposure time to achieve lens projection aperture of about two stops down from full.

    *Grain focuser working properly? Thickness of the print paper added when grain focuser is being used?


    Bernice

Similar Threads

  1. Why are my pictures not crisp
    By Raffay in forum Darkroom: Film, Processing & Printing
    Replies: 39
    Last Post: 25-Apr-2013, 12:10
  2. Best scanner for crisp, high magnification..
    By walkerbl in forum Digital Hardware
    Replies: 7
    Last Post: 15-Jan-2010, 17:40
  3. DD-X compared to XTOL?
    By Ron Marshall in forum Darkroom: Film, Processing & Printing
    Replies: 6
    Last Post: 16-Feb-2007, 07:44
  4. FP4 compared to Plus-X?
    By Erik Asgeirsson in forum Darkroom: Film, Processing & Printing
    Replies: 11
    Last Post: 9-May-2001, 02:25

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •