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Thread: Focusing 90mm

  1. #1

    Join Date
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    Focusing 90mm

    Hi,

    I'm still new to LF, yet to expose my first frame. I bought 'Using the View Camera' but was very disappointed with it, far too much information about lenses and theory and almost nothing about how to set up and use the camera in the real world.
    I didn't want to ask this question until I had read it, not wanting to sound stupid, but how do I focus my 90mm? With my 210mm it focuses fine but the front standard doesn't go back far enough
    with the 90mm, I'm using a Tachihara 45.
    I'm assuming that I have to move the back standard forward across the camera bed, but how much, to what point, etc, etc?
    Another question, how do I know when I've focused past the point where I need to add compensation for bellows draw, is there a set distance or do I just need to be careful when I start out focusing to make sure I haven't run past infinity?

    On an aside, I've seen in use cameras that have a compacting bellows arrangement on the back for use with the focusing screen. It would seem to me that using such a hood would be great for the intial composing of the image while swopping to the hood for focusing, less tedious than having to come out of the hood each time to adjust composition. Does such a thing exist or are they all mono/binocular view arrangements?

    Many thanks.

  2. #2

    Join Date
    Sep 2003
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    1,791

    Re: Focusing 90mm

    Each lens is a little different. But a 90mm needs about 90m to focus. Likely a little more. I think mine needs 98 mm to make infinity focus.

    Bellows factor can be handled by the formula. Odds are in landscape use you'll not need it. OTOH for macros or other closer work some think like the disc works fine.

    http://www.salzgeber.at/disc/

  3. #3

    Re: Focusing 90mm

    Move the back standard all the way forward, you can always rack the front standard out to then make focus at infinity.

  4. #4

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    Re: Focusing 90mm

    Like Dean, I move the back standard all the way forward and pull back the front standard past the focus point, about 5cm. From there you can rack out using the focus knob.

    As a simple way to find the Bellows Factor, you can add 1/2-stop of exposure for every additional extension (from infinity) of 1/4 the focal length.

  5. #5
    kev curry's Avatar
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    Re: Focusing 90mm

    Ben I use my 90mm mounted in a recessed lens board on my Tachi and find it straight forward to focus. Once the camera is set up and the lens is mounted the first thing I do
    is push the rear standard all the way along the bed till it stops then use the front standard to focus as normal. Remember than you can unlock the front standard and move it along the bed closer to the rear standard and once locked down begin using the focusing knob to achieve focus. This is assuming I'm doing landscape shots.
    If you go back and have a read through 'Using the View Camera' under the heading 'Calculating the right exposure' page 70 in my copy, theres a very clear and simple explanation on how to calculate for bellows extension. I say simple but I have to read things like this about ten times till it 'clicks'! The 'rule of thumb' method that Steve Simmons gives works a treat for me!

    Best of luck.

  6. #6

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    Re: Focusing 90mm

    Thanks to all, calculating extension compensation isn't the problem, it's making sure that I haven't strayed unwillingly into bellows extension territory!

  7. #7
    Whatever David A. Goldfarb's Avatar
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    Re: Focusing 90mm

    Think of it this way--if you're shooting landscapes with 4x5", unless you are filling the frame with something that is 40x50" or smaller, you won't have to think about bellows factor. If you're indoors, or shooting a portrait, still life, or macro, chances are you will have to calculate the bellows factor.

  8. #8

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    Re: Focusing 90mm

    Well, I just went outside and tried it, I have to push the backstandard all the way forward and the front standard pretty far back. To be honest I'd have loved a proper manual with this camera

    I'd been doing a bit of research, I had an idea of fitting the lens shade from a speed graphic onto my Tachi, well I was trying to focus outdoors in pretty dull light and I couldn't see a thing however shaded I made the screen, until I put the hood on. Oh well, it was an idea...

  9. #9
    Whatever David A. Goldfarb's Avatar
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    Re: Focusing 90mm

    Most view cameras don't come with much of a manual, since most of them are pretty similar to each other, except for a few exotic features like asymmetric tilts and such.

    Steve Simmons' book does cover all the basics, and you might look at Stroebel's _View Camera Technique_ when you want more depth on particular issues.

  10. #10

    Re: Focusing 90mm


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