Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,548   Posts: 1,544,538   Online: 995
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 16

Thread: Focus Movement?

  1. #1

    Join Date
    Sep 2013
    Location
    Omaha, NE
    Shooter
    Medium Format
    Posts
    46
    Images
    6

    Focus Movement?

    I have noticed that when I turn on the enlarger focus the grain, turn it off for a moment, and turn it back on while looking through my grain magnifier the grain is not sharp until the light has been on for a few seconds. Is this normal?

  2. #2

    Join Date
    Jan 2014
    Location
    California desert
    Shooter
    35mm
    Posts
    740

    no

    Does not sound right. Maybe you have some creep in the darkroom --- whoops, I mean some creep in the enlarger. Is there a focus lock? The focus knob or mechanism should be a bit stiff, so there won't be any creep.

  3. #3

    Join Date
    Sep 2013
    Location
    Omaha, NE
    Shooter
    Medium Format
    Posts
    46
    Images
    6
    Quote Originally Posted by snapguy View Post
    Does not sound right. Maybe you have some creep in the darkroom --- whoops, I mean some creep in the enlarger. Is there a focus lock? The focus knob or mechanism should be a bit stiff, so there won't be any creep.
    I thought about that, but the focus comes right back to where I had it properly adjusted after a few seconds with the light source on. The focus knob is quite stiff, and the elevation knob clamps down tight. The effect is very slight and can only be seen through the magnifier. I only noticed because I began looking through the magnifier before I turned on the enlarger once.

  4. #4

    Join Date
    Jan 2009
    Location
    Los Angeles
    Shooter
    Multi Format
    Posts
    1,914
    Images
    54
    Can only think about the negative UN-buckling when the light source is turned off . The light has been on for a little while when I focus the the neg so it is probably all ready buckled by that time. Although now I have a glass carrier so no buckling. One other thing I recall when focusing was flexing of the negative in the carrier, due to the fact the bellows is almost air tight which caused a slight difference of air pressure inside to that of the outside air making the negative flex while focusing.
    Last edited by mike c; 07-19-2014 at 10:27 PM. Click to view previous post history.

  5. #5
    ic-racer's Avatar
    Join Date
    Feb 2007
    Location
    Midwest USA
    Shooter
    Multi Format
    Posts
    6,219
    This is normal behavior when not using a glass carrier.

  6. #6

    Join Date
    Sep 2013
    Location
    Omaha, NE
    Shooter
    Medium Format
    Posts
    46
    Images
    6
    Quote Originally Posted by ic-racer View Post
    This is normal behavior when not using a glass carrier.
    Okay. So, I suppose optimum results using a normal carrier involve turning on the enlarger with a piece of cardboard over the lens, waiting, and quickly moving the cardboard out of the way while starting the timer?

  7. #7
    winger's Avatar
    Join Date
    Jan 2005
    Location
    Page County, IA
    Shooter
    Multi Format
    Posts
    2,419
    Images
    47
    Quote Originally Posted by Nathan King View Post
    Okay. So, I suppose optimum results using a normal carrier involve turning on the enlarger with a piece of cardboard over the lens, waiting, and quickly moving the cardboard out of the way while starting the timer?
    No, the normal way to use a glass-less carrier is to turn it on to focus and leave it on for a bit before focusing. It's the heat from the lamp that's warming the negative and then the negative pops a bit. If you warm it up, then focus, then get the paper ready quickly so it doesn't pop back while the light is off, you should be able to expose the print with the neg focused. Or buy a glass carrier. If you take a long time between focusing and getting the paper in place, the negative cools back off and pops into its original spot. This is more common with 120 or 4x5 than with 35mm. I've actually never had it happen with 35mm. I would also never do 4x5 without glass.

  8. #8
    Jim Jones's Avatar
    Join Date
    Jan 2006
    Location
    Rural NW Missouri
    Shooter
    4x5 Format
    Posts
    1,816
    Negatives tended to pop in my Omega B-22 during lengthy darkroom sessions. One way to eliminate this is to leave the enlarger on all the time and control the exposure with the red focusing filter.

  9. #9

    Join Date
    Feb 2004
    Location
    Maryland
    Shooter
    Multi Format
    Posts
    97
    This was a problem with my D-2 until I installed heat absorbing glass. Eliminated the problem once and for all when I replaced the PH211 with an LED head.

  10. #10

    Join Date
    Sep 2013
    Location
    Omaha, NE
    Shooter
    Medium Format
    Posts
    46
    Images
    6
    I will have to get some heat absorbing glass. I have remedied the issue in the interim by loading the paper, turning on the enlarger with a gray card covering the lens, letting it warm for five or so seconds and beginning the exposure. I tried preheating the negative, but the time it takes me to situate the fiber paper (which curls upwards and doesn't want to fit into the slot) and make sure it is perfectly situated for an even border allows the negative to cool enough to become an issue. I have compared prints with a loupe and have found slightly sharper grain allowing the negative to heat prior to exposure.

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