Wide angles and bag bellows

Discussion in 'Large Format Cameras and Accessories' started by Nomad, Mar 2, 2011.

  1. Nomad

    Nomad Member

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    Apologies for what is probably a newbie question.

    I have an MPP 5x4 monorail with the standard bellows and a 150mm lens. I'm planning to shoot a series of photos of a large construction project in my area, over a period of time, all from the same vantage point. My calculations suggest I will need a wider lens, and a 90mm would seem to fit the bill.

    All of my lens boards are flat panels - no reccessed ones. The shots will be a general view of the subject, effectively straight shots at infinity focus - don't expect to need any movements.

    Am I likely to need a bag bellows? How about a recessed lens board?

    While I'm here, is anyone aware of other makes of lens board that fit the MPP?
     
  2. George Collier

    George Collier Member

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    When I bought my 90mm for my 4x5 Cambo, it came mounted to a recessed board. I also bought a bag bellows for movements. I don't know any reason not to have the lens mounted to a recessed board, although you might need an "angled" cable release adapter to access the place on the lens barrel. Once I had the bag bellows, I never carried the long bellows with me again (including for the 210mm lens) unless I knew I was going to do work at less than 3-5 feet from the subject.
    This is my situation, I don't know how it would apply to you. There are others on this forum with more gear knowledge. It might be useful to know what camera you have.
     
  3. Ian C

    Ian C Member

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    The lens is closest to the film when focused at infinity. At that point the center of most lenses is the distance f from the film. The center of the lens is usually about the plane of the diaphragm, except for telephoto designs where the “crossover” point falls forward of the diaphragm and, sometimes, forward of the entire lens.

    The “crossover” point on a wide-angle lens may be somewhat displaced from the apparent center, but usually not by much.

    The diaphragm generally is at the back of the shutter just forward of the front of the lens boardas mounted.

    If you mount a flat lens board onto the camera and can place the front of the board at the distance f from the film plane, then you can focus at infinity without a recessed board.

    If the design of the camera prevents placing the board at that position, then a recessed board is needed. Cambo cameras require a recessed board for lenses of about 100mm or shorter.

    If the bellows can compress enough to let the board (or recessed board if necessary) reach the correct position, then a bag bellows isn’t need. Otherwise the bag bellows is needed.

    For the camera you described the recessed board is probably necessary, but the bag bellows might be optional. By performing the above outlined distance test with your existing bellows and recessed lens board you can probably determine if the bag bellows are required.
     
  4. Hikari

    Hikari Member

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    If you are using no movements, then you don't need a bag bellows. Whether you need a recessed lens board depends on how close the front and rear standards can come together. I would imagine you will be fine with a flat board. I have never had my 90mm lenses on a recessed lens board and the standard bellows allowed enough movement for what I needed to do. Recessed lens boards are a bit of a pain.
     
  5. Jesper

    Jesper Subscriber

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    I agree with Hikari.
    I use my 90:s on flat boards and do not change to bag bellows to use them. I think it will be fine on your MPP.
     
  6. RalphLambrecht

    RalphLambrecht Subscriber

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    I also believe that you'll be fine with a recessed lens board and don't need bag bellows. Most wide-angle lenses have such a small image circle that you will vignette before you'll run out of movements. Nevertheless, the recessed board will ease infinity focus without squeezing the bellows too much.
     
  7. Ian Grant

    Ian Grant Subscriber

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    As Ralph says you won't need bag bellows. However you need to check because I think the MPP actually uses a cone not a recessed board for a 90mm lens, this is so the standard sits in the body while the front is dropped so the opposite of what you'd expect. This would make sense as with a Pakemaker Graphic at Infinity a 90mm sits just on the outside of the caseing on the drop-board.

    A 90mm lens needs significantly less movement than a 150mm, it's more responsive to slight rise/fall/shift/tilt etc and so even with a cone you should have enough movements.

    Ian
     
  8. Dan Fromm

    Dan Fromm Member

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    Ian, the OP has an MPP monorail.
     
  9. Ian Grant

    Ian Grant Subscriber

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    Good point Dan.

    Then a recessed board may hel, I never think of their monorails as everyone I know with MPP's have MicroTechnicals (or MicroPress).

    Ian
     
  10. paul_c5x4

    paul_c5x4 Subscriber

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    Judging by the dimensions given over on the MPP Users web site, the lens boards are 139mm square and appear to be a close match for Sinar(F?) panel that I have in front of me.
     
  11. Nomad

    Nomad Member

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    Thanks for all the replies, folks.

    Yes, just been looking at lens boards on eBay, and Sinar look to be the same - one in particular with good photos showed that it has the same lip on the inside to slot into the recess in the front standard, and even has the same Hammerite-style grey paint finish on the outside. Given that this Sinar, and my MPP panels, all have a silvery foil name sticker, my guess is that they were made by the same company back in the day. I think the nominal size is probably 5.5 inches.

    I just did some measuring using a lens board with no lens, with the standards set as close as they'll go. From the outer surface of the board to the ground glass, I got 87mm. I think that means I'm in the clear for using a 90mm. Even if it turns out that infinity focus can't be acheived, I should be able to get enough sharpness by stopping down. If a recessed board really is needed, it's good to know that there might be an option with the Sinar ones - I don't think I've ever seen a recessed baord for the MPP monorail. If that can't be found, there is always the option of making one from from a flat board.