Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 69,745   Posts: 1,515,607   Online: 958
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 18

Thread: Focusing

  1. #1

    Join Date
    Sep 2002
    Posts
    158
    Once I started enlarging 4x5 negatives I had trouble using grain focusers because there wasn't much grain. Is there a technique or a special type of focuser that could make it easier? Thanks.

  2. #2

    Join Date
    Sep 2002
    Location
    Nuernberg, Germany
    Posts
    214
    Fine grained film and LF negs will have this effect on anyone and just about any grain magnifier. You might want to try one that has a higher magnification such as 25X. The average ones use around a 6 or 7X I believe.

    When I have this problem of not being able to see the grain, I usually look for an area of the negative that will give me a small, fine and delineated sorce to judge the sharpness such as eyelashes, a zipper works well too.
    - William Levitt

  3. #3

    Join Date
    Sep 2002
    Shooter
    Large Format
    Posts
    4,530
    I look for straight edges. The Peak enlarging focusing gizmo is great....expensive though.

  4. #4

    Join Date
    Sep 2002
    Location
    Pikes Peak
    Posts
    205
    I find that a Magna Site image magnifier is adequate for most negatives that have detail and contrast. I also have a Peak 2 that I don't often use because while it works well (more accurate on neg with little detail) I find it harder to use and have found that the results from the Mag are mostly equal. I am glad I found a deal on a used Peak as new they are very very expensive and I would be kicking myself.

  5. #5
    Les McLean's Avatar
    Join Date
    Oct 2002
    Location
    Northern England on the Scottish border
    Shooter
    Multi Format
    Posts
    1,610
    I look for an area of the image where the highlight and shadow meet and straddle the focussing tool across both. This is particularly efficient if this happens to fall on a straight edge as suggested by Jorge.
    "Digital circuits are made from analogue parts"
    Fourtune Cookie-Brooklyn May 2006

    Website: www.lesmcleanphotography.com

  6. #6

    Join Date
    Sep 2002
    Location
    Willamette Valley, Oregon
    Shooter
    Medium Format
    Posts
    3,684
    </span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Prime @ Oct 29 2002, 10:28 PM)</td></tr><tr><td id='QUOTE'>Is there a technique or a special type of focuser that could make it easier?</td></tr></table><span id='postcolor'>
    Try a pair of the strongest reading glasses available. They are handy for
    cleaning and close inspections. Nice to have around. Ditto handled
    magnafiers. Dan

  7. #7
    edz
    edz is offline

    Join Date
    Dec 2002
    Location
    Munich, Germany
    Shooter
    Multi Format
    Posts
    685
    </span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Prime @ Oct 29 2002, 08:28 PM)</td></tr><tr><td id='QUOTE'>Once I started enlarging 4x5 negatives I had trouble using grain focusers because there wasn&#39;t much grain. &nbsp;Is there a technique or a special type of focuser that could make it easier? &nbsp;Thanks.</td></tr></table><span id='postcolor'>
    The kind of focuser assist appropriate are those with a focusing screen and less the, albeit fashionable, microscope variety. Durst and Linhof had made some excellent units with built-in magnification and Paterson once upon a time had a low cost focuser with a large screen and no magnification. They tend--- even with films and formats where the grain is more clearly defined--- to be more accurate than the arial projection designs. The microscope units I think are appropriate for less than solid enlargers with glass-less negative carriers that by virtue of their construction are ill-suited to the use of focusing negatives.
    Edward C. Zimmermann
    BSn R&D // http://www.nonmonotonic.net

  8. #8
    Ed Sukach's Avatar
    Join Date
    Nov 2002
    Location
    Ipswich, Massachusetts, USA
    Shooter
    Medium Format
    Posts
    4,520
    Images
    26
    </span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Prime @ Oct 29 2002, 08:28 PM)</td></tr><tr><td id='QUOTE'>Once I started enlarging 4x5 negatives I had trouble using grain focusers because there wasn&#39;t much grain. &nbsp;Is there a technique or a special type of focuser that could make it easier? &nbsp;Thanks.</td></tr></table><span id='postcolor'>
    I might suggest the obvious:

    It may help to focus with the enlarging lens aperture wide open. In addition to providing the most illumination possible, it will make the apparent field of focus narrower and the ideal focus will be more easily seen.

    Second, there is always the option of using a "Substiitute - Test" negative, either/ or a coarse-grained image or gray field (read: Fast film developed in Rodinal) or one with a fine pattern (lines, dots, resolution target, etc.) to be used for focusing and then replaced with the "real" negative.
    Carpe erratum!!

    Ed Sukach, FFP.

  9. #9

    Join Date
    Sep 2002
    Location
    France
    Shooter
    Multi Format
    Posts
    357
    </span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Ed Sukach @ Dec 13 2002, 03:08 PM)</td></tr><tr><td id='QUOTE'>It may help to focus with the enlarging lens aperture wide open. &nbsp;In addition to providing the most illumination possible, it will make the apparent field of focus narrower and the ideal focus will be more easily seen.</td></tr></table><span id='postcolor'>
    Ed,

    although your suggestion is based on common experience, you will find that more than a few enlarger lenses will show a significant focus shift when stopped down. Although enlarger lenses are designed for flat field projection, the practical performance is always a compromise within the variety of possible magnification factors and apertures.

    Apart from that, the performance of an enlarger lens can be bad wide open making it difficult to find any sharp grain. In my experience, it is always better to use the grain magnifier at working apertures. If the grain is sharp, your picture will be sharp, too, no matter how many degrees you can turn your focus knob around this. However, if you check the edges, too, you will see that there is usually not that much tolerance.

    Regarding the original question: if your magnification ratio is too small to get any aid from a grain magnifier, you will not need one. You will need neither the resolution nor the brightness (shorter times) of larger apertures. Simply focus with your eyes and stop down 3-4 f-stops. If your image is intentionally out of focus (i.e. contains no reference details), judge case by the case. Small magnification ratios reduce the visual impact of unsharpness and you may find it useful to add some defocus while printing. In this case, the use of a grain magnifier may even deteriorate your results.

  10. #10
    David A. Goldfarb's Avatar
    Join Date
    Sep 2002
    Location
    Honolulu, Hawai'i
    Shooter
    Large Format
    Posts
    17,135
    Images
    20
    I agree--you should always double check for focus shift at working apertures. You would be surprised, but some otherwise very good lenses have this problem.
    flickr--http://www.flickr.com/photos/davidagoldfarb/
    Photography (not as up to date as the flickr site)--http://www.davidagoldfarb.com/photo
    Academic (Slavic and Comparative Literature)--http://www.davidagoldfarb.com

Page 1 of 2 12 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin