Focusing Techniques

Discussion in 'Large Format Cameras and Accessories' started by Terry Bowyer, Nov 29, 2008.

  1. Terry Bowyer

    Terry Bowyer Member

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    I would like to get people opinion of their focusing technique for their large format camera. My main interest is landscape photography, and would like to achieve a pin sharp as possible photograph from foreground to infinity. Before I start exposing film it would be interesting to know if I am doing something blatently wrong.

    What I cant find out is if I have the lens wide open to be able to see the whole image in the ground glass. How do I focus so both foreground and background is in focus. I could stop down to my desired F-stop, and refocus, but then cant see the whole image in the ground glass.

    thanks in advance for any help.
     
  2. rwyoung

    rwyoung Member

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    Use a good darkcloth and you will be able to see the image on the GG with your lens stopped down. Blackjacket is a pretty good one.

    Also, learn how the movements work on your camera. Using those and having your lens wide open you can get nearly everything focused. But be sure to check the GG for image coverage. Simplest is to peek in from the corners of the glass (clipped glass is best for this) and if you can see the aperture and it is round chances are you are OK. Then stopping down to about the middle of the range should get you what you need. This is of course a gross oversimplification and each situation is unique.

    Finally, get a nice loupe. Lately I've just been using a small folding pocket magnifier, about 5x, and it works quite well for me. With my glasses on I can pull focus without needing to rub my nose on the GG.

    If you haven't already gotten you hands on a copy, two good reading recomendations:
    1) Steve Simon's book, Using the View Camera
    2) Bruce Barlow's eBook, Finely Focused

    Steve's is good for mechanics and the basics. Bruce's adds lots more on technique in using the camera and prepairing the mind (so to speak) for LF photography.
     
  3. MurrayMinchin

    MurrayMinchin Membership Council Council

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    Focus on the far, then tilt for the near. You can either tilt the lens, or you can tilt the back if you don't mind converging verticals or want to accentuate some sweeping foreground shapes, such as roots. You'll have to refocus and retilt a few times just a little to dial it in, then stop down a wee bit to be sure, especially if there's anything tall like trees involved. Just play around with it and all will become clear :smile:

    Murray
     
    Last edited by a moderator: Nov 29, 2008
  4. jeroldharter

    jeroldharter Member

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    Focus on the far (the bottom of the ground glass), then tilt the front standard for the near (the top of the ground glass). Then fiddle with the focus a little if need be. I think a front axis tilt is the easiest way to get started if you have it. Rear tilts can cause some focus issues with tall objects placed between near and far requiring more stopping down to compensate. If it is just an open air horizon without trees or other objects in the middle then no problem.

    Rod Klucas at Precision Camera has a focus method which involves simple measurements on the camera while focusing but I have not had a chance to try it out yet.
     
  5. ragc

    ragc Member

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    All of the above, plus: Use wide-angle lenses for deeper DOF. Focus 2/3 of the distance to the horizon, then stop down, ensure the horizon is sharp and tilt for foreground.
     
  6. GraemeMitchell

    GraemeMitchell Member

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  7. Martin Aislabie

    Martin Aislabie Subscriber

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    In order to see the Ground Glass well enough to check the focus – both Lens open and stopped down, the GG has to always be brighter than where you are viewing it from.

    A good Darkcloth is therefore ESSENTIAL – it’s a balance between darkness/claustrophobia/access/temperature. Its very much a personal choice.

    I found a Wide Angle Fresnel helped enormously to brighten the GG - http://www.badgergraphic.com/store/cart.php?m=product_detail&p=1156

    Of course it only works on Wide Angles lenses (up to 150mm) but if you are doing Landscape I assume you will be using Wide Angle Lenses.

    I use a Schneider X6 Lupe to check the focus but I wonder is the Rodenstock version with its square skirt might not be a better bet to enable you to get right into the corners of the Ground Glass (the corners are where I struggle to check focus due to the Schneiders’ round skirt)

    A good Lupe (Schneider/Rodenstock) is worth its weight in gold – I initially bought cheaper one and regretted it - and now only use to check Negs on a Light Box.

    I also use one of these - http://www.badgergraphic.com/store/cart.php?m=product_detail&p=2164

    I use a pencil to mark the difference in focusing length of the front standard at near/far and work out the required aperture – then add one

    But I still stop the lens down and check anyway – just in case.

    Good luck and have fun :smile:

    Martin
     
  8. Matt5791

    Matt5791 Subscriber

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    Interesting thread - I too have been getting to grips with focusing - I have an Agfa Ansco 5x7 with an up to date Schneider 120mm f8 lens.

    The problem is that this camera has no front tilt - what I have tried is tilting the whole camera and then re adjusting the back to vertical - What I am unsure about is whether this is achieving the same result of a tilting front?

    Thanks for any help.

    Matt
     
  9. ic-racer

    ic-racer Member

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    Its not a trick or a secret, it is just the obvious. The only way to achieve the above is to arrange your composition so that your important elements fall in the same plane.

    You can't go beyond the physics of the system. There is only ONE plane of focus; do with it what you like, but realize that if your subject does not fall on that plane, it will be out of focus.
     
  10. Ian Grant

    Ian Grant Subscriber

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    It can, but your camera doesn't have much rear tilt so it may be insufficient. I have to make an adjustable tilting lens board for my 2nd 18x8 Agfa Ansco as it's similar to yours. I figure that next time I'm back in the UK we could meet up and see what can be made easily.

    Ian
     
  11. eric johnson

    eric johnson Member

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    As suggested, get one of the basic large format intro books or take a look at the beginner's series with diagrams that is appearing in View Camera. Both have been a big help to me. No math, and very little complication, just good basic information.

    eric