Zeroing out a field camera (Beginner Question)

Discussion in 'Large Format' started by bradley_artigue|2, Apr 21, 2005.

  1. After reading multiple posts here and spending about six months of
    research I bit the bullet and picked up an Ebody RW45. I'm
    overwhelmed by the quality of the camera (my previous LF was an
    Omega-View monorail which lacked the finer points of precision).

    Question is - what's the right way to zero out a 4x5? By this I
    mean the front lens board is slightly offset (the lens is mounted
    off-center towards the bottom of the square). So what is the "zero"
    position, where the center of the lens strikes the center of film?

    I guess I'm asking (a) does it matter - I tend to compose with my
    eyes and not with a ruler and calculator and (b) if it does matter,
    what's the right way to establish the position?

    The Ebony has indents for zeroing everything except the lens (for
    the obvious reason that the lens can be mounted in a different
    position depending on the lens/board combination).

    Thanks in advance. I fired off a few shots and am just amazed; the
    super symmar apo i picked up with the Ebony really blows the old
    angulon I have on the monorail away.
     
  2. If I understand your question correctly I would not be concerned about the location of the hole in the lensboard. I assume that you are using an Ebony board or a generic board for the Ebony. I have the SV45U2 and just zero everything out using the marks provided for that purpose. Never a problem.
     
  3. Brad,

    The standards have "dots" on them to line up the offset boards. The difference between offset and non-offset is 8mm IIRC, so not an issue in most cases.

    Steve
     
  4. Bradley, The offset lens is not an issue. I have an Ebony 45s and on the front standard (the titanium part, I believe) has a red dot that matches with a white dot on the wooden part. That should zero out the rise. Hope that helps.
     
  5. IIRC (and I may not, it's been a while) Linhof offsets its lens boards because the design of the Linhof cameras is such that offsetting actually centers the hole on the film. Ebony (and otner) cameras are made to accept Linhof type boards and the cameras may be designed the same way (i.e. so that offsetting is actually centered). I've owned a couple Ebony cameras but I don't remember whether this is the case with their design or not. Regardless though, it isn't a question of how you see or of using a ruler and calculator to determine what will be included on the film, it's just a question of whether the center of the hole is at the center of the film or is slightly off-center. In theory, if the image circle was small enough you could lose some sharpness if you centered an offset board because a portion of the image would fall at the outer edges of the image circle where lenses often aren't as sharp as at the center. As a practical matter the difference between being perfectly centered and being slightly offsetis so small that I don't think it really matters.
     
  6. If your lens has reasonable coverage, it shouldn't matter much whether you are exactly centered or not. I generally use a rise or fall anyway to frame the picture the way I want it, so centering is not usually an issue.
     
  7. pvp

    pvp

    I agree that it just isn't very important. (Granted that there are laboratory applications where it might be, few -- if any -- of the participants on these forums are doing such photography.) The bottom line is that LF cameras are the ultimate WYSIWYG user interface. What you see on the groundglass is what the film will see. So, while it's handy to have the camera more-or-less zeroed when you begin composing, that's only to simplify the thinking process. Ultimately you're going to move things around until you like what you see. Unless you need to accurately measure and record the amount of tilt, rise, etc...

    "Close" is close enough.
     
  8. Thanks everyone, I figure that if the image is what I want on the film it really doesn't matter if the lens started, finished, or was ever at zero.
     

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