Do you adjust your aperture?

Discussion in 'Large Format Cameras and Accessories' started by malcao, Sep 14, 2009.

  1. malcao

    malcao Member

    Messages:
    55
    Joined:
    Dec 29, 2008
    Location:
    Sweden
    Shooter:
    Multi Format
    I'm aware of that the shutter speed isn't exact but how about the aperture? It never crossed my mind until I bought my second Schneider 360mm (400€ looks like new, couldn't let it pass :smile:
    When comparing them I notice that they differ by about 1/3 stop.
    Anyone had any thoughts about this and do you adjust your aperture?
     
  2. EASmithV

    EASmithV Member

    Messages:
    1,925
    Joined:
    Aug 22, 2008
    Location:
    Maryland
    Shooter:
    Multi Format
    Is it possible that while maintaining the same overall appearance, there was a slight modification in the design and the aperture was changed? The only thing I can think of is to stick a flat art incident meter in the back of your view camera, and use it to re-mark your f stop markings. Alternatively, it's possible that the f stop scale can be loosened with a set screw and then rotated to be calibrated, but I'm, not familiar with your particular lens.

    PS; I'm surprised that no one else has commented on this yet... Unusual for APUG...
     
  3. Ian Grant

    Ian Grant Subscriber

    Messages:
    18,030
    Joined:
    Aug 2, 2004
    Location:
    West Midland
    Shooter:
    Multi Format
    Well an Uncoated, Single coated and Multi-coated lens design of the same aperture will pass differing amounts of light.

    In practice there's very little difference between my single (& well) coated 1950's 150mm T CZJ Tessar and my Multi-coated Schneider's & Rodenstock's. So there's no need to make any adjustment.

    Ian
     
  4. bsdunek

    bsdunek Subscriber

    Messages:
    1,351
    Joined:
    Jul 27, 2006
    Location:
    Michigan
    Shooter:
    Multi Format
    This comes under knowing your equipment. If you are in a situation where exposure is very critical, you know the differences in your lenses and can compensate accordingly. I have an old Gossen light meter that reads about 1/2 stop high. Otherwise it is fine, so I just remember that.
     
  5. ic-racer

    ic-racer Member

    Messages:
    7,470
    Joined:
    Feb 25, 2007
    Location:
    Midwest USA
    Shooter:
    Multi Format
    Your aperture scale may not be the correct one for the lens. Making aperture scales and /or calibrating them is certainly somethig LF photographers are interested in. There are many threads on this topic.
     
  6. Ed Sukach

    Ed Sukach Member

    Messages:
    4,518
    Joined:
    Nov 27, 2002
    Location:
    Ipswich, Mas
    Shooter:
    Medium Format
    It may be of use to rememebger that the exposure is determined by the ACTUAL f/stop, where f/= distance to film plane / aperture diameter. The lens, accompanied by the aperture, is normally extended out beyond the "Infinity Focal Length" when taking anything closer than "infinity focus" - most noticable in "close-up" photography. Many "bellows equiped cameras wil have an exposure compensation scale linked to the bellows.
    Most lenses have the apertures marked for infinity focal length, and will automatically underexpose.

    Another photographic anomally, "inaccurate f/stops", worthy of consideration.
     
  7. BrianShaw

    BrianShaw Member

    Messages:
    6,656
    Joined:
    Nov 30, 2005
    Location:
    Los Angeles,
    Shooter:
    Multi Format
    I have never been bothered by the minor exposure differences except those of greater magnitude from poor shutter speed performance. So, no, I have never even thought of adjusting (calibrating) aperture.
     
  8. John Koehrer

    John Koehrer Subscriber

    Messages:
    6,368
    Joined:
    Apr 3, 2004
    Location:
    Montgomery,
    Shooter:
    Multi Format
    I'm not sure you can adjust the aperture. The blades are fixed to the blade operating ring & that's it.
    You might be able to fudge with the maximum aperture but it wouldn't have any effect on the rest of them.
    Grimes may be able to test the lens & make you a new f-stop plate for $$$.
     
  9. Mike1234

    Mike1234 Inactive

    Messages:
    1,884
    Joined:
    Jul 6, 2009
    Location:
    South Texas,
    Shooter:
    4x5 Format
    I'm just repeating others here but... if need be you could make a new aperture scale calibrated to the lens (or have one made), or you could tape a paper one over the existing scale, or you could just keep a chart of corrections and adjust by that. As others have stated, the scale "should" be very accurate unless there's something awry.
     
  10. malcao

    malcao Member

    Messages:
    55
    Joined:
    Dec 29, 2008
    Location:
    Sweden
    Shooter:
    Multi Format
    On the 360/6.8 Symmar-S you can adjust the aperture at both the start point and end point. I changed one of the lenses so they appear to be more or less the same. Before you could just notice the aperture blades at 6.8 if you move the stop screw one pinhole you will have a full opening and go past 6.8 on the aperture scale, I'm not sure if this mean 5.6 anyway it's nice to have the option to shoot wide open.