Movement restriction questions - manygreenspun.com : LUSENET : Large format photography : One Thread
Using a 90mm lens on a camera offering 60mm minimum bellows extension (Ebony 45s)would leave 30mm draw from minimum at infinity focus. I know my likely working focus distances would be longer than that, but nonetheless it seems like a rather small amount of bellows available for movements. How much would movements be restricted? Which movements would be restricted the most? How much of a hazard are recessed boards, is it just the aggravation of accessing lens settings, or are there other considerations? I live in a small community with no LF presence anywhere, so the pleasure of going to a dealer and playing with the camera is not an option. I've searched previous similiar threads, but would like more accurate answers. For example, at say 100mm bellows extension, how much of maxiumum 20 degrees front axis tilt would be lost? (I would guess none).How much of maximum 50mm back rise would be unavailable? How about combinations of movements? I know a bag bellows would solve most movement restrictions, but I'm wondering about the standard 60-270mm bellows. Please forgive all the questions, but I'm a beginner unable to afford a mistake in my purchase. Many thanks in advance.
-- Mike Mahoney (email@example.com), March 05, 2001
You need a bag bellows. The restriction on a normal bellows is the rigidity of the bellow itself; at minimum draw it is solid, and no movements are normally possible, at at maximum draw you can expect much the same problem. You don't say what sort of photography you are doing, but presumably you will be using this 90mm lens for either landscapes or architecture, neither or which normally require a lot in the way of movements. You seem to be talking in the future tense, so I assume that you haven't actually got the lens yet. No problem. Any lens, or none at all, will allow you to test movements. Pretend that you have a 90mm lens fitted and 'focus' at infinity, i.e. with 90mm of bellows draw. Now try the movements and see how far the bellows will allow you to swing, tilt and shift without placing undue strain on the bellows. Then repeat with 180mm bellows draw, so that in effect you are shooting at 1:1. Then try it at whatever intermediate settings you think you will be using. There will be very little difference in bellows draw at any 'normal' shooting distance. I'm not a great lover of recessed lens mounts, although they can be essential for very wide lenses, they can be a pain to use and I have usually found it necessary to remove the lens panel to set the lens etc. Your best answer, as I said right at the start, is to use a bag bellows, but even this is not always a complete answer because, especially when shifts are being used, you can end up with a fold in the bellows that partially obstucts the film or the lens. Easily corrected, but you have to look out for it and polaroids are the only real way of making sure.
-- Garry Edwards (firstname.lastname@example.org), March 05, 2001.
I agree with Garry. A bag bellows is the way to go. I tried to get by without one when using my 90, and I quickly found myself running into bellows crunch with anything more than slight movements. Try it and you can feel the bellows straining and pushing against the front standard. Once I got a bag bellows I could have slapped myself for waiting so long. Movements are easy and there is no concern that the front standard is going to be pushed in any direction. The big plus of course is being able to take full advantage of all available movements when you need to, as will happen photographing buildings and such.
-- Erik Gould (email@example.com), March 05, 2001.
Garry and Erik, do either of you have a sense for the longest lens that can be used with the bag bellows on the Ebony? That might help Mike justify the bb purchase. I initially shied away from purchasing the bag bellows for my (non-Ebony) 4x5 because I didn't want to always have to carry two sets of bellows, but (as with Erik) after I bought it I couldn't believe I'd tried to go without it (them?). Although the camera makers usually downplay the "long" end of bag bellows capacity, with mine I can focus a 210mm at a foot and a half or so even with some movements, and it's a breeze for 120-150mm.
-- Simon (firstname.lastname@example.org), March 05, 2001.
Mike, check with Ebony or your Ebony dealer but it looks from their catalogue that wide angle/bag bellows are not required with the 45S. It looks like they use the same type of very supple bellows material has they do on the SW45 (which I use) and providing the lens has the coverage 50mm rise is no problem.
With regrads recessed lens panels you will only need to use one on lenses from 47 to 35 on the 45S. The Ebony recessed panels are easy to use they have an offset cam for the cable release the only thing you need to operate within the recess is the aperture and shutter. All the best,
-- Trevor Crone (email@example.com), March 05, 2001.
Thank you for all replys. I didn't make clear in my original post that I am considering purchasing both camera and lens together. My main use is landscape and I had used a 45mm on a 67 Pentax for years, almost to the exclusion of other focal lengths, so 90mm in 4x5 should be the approx. equivalent. I researched LF cameras as best I could, and the Ebony 45s seemed to be WA friendly but also offered a 270mm max bellows, and I felt it a good comprimise should other focal lengths be used in the future. Does a tapered bellows help with movements at short extensions? According to Ebony, you should be able to use a lens shorter than a 90 with no problems. But when I drew a diagram to scale on paper things seemed a little tight, hence my questions.
-- Mike Mahoney (firstname.lastname@example.org), March 05, 2001.
Mike, if you liked very wide angle 45mm for your 6x7 shooting, you might consider saving and going with the wider 80mm, 75mm or 72mm for 4x5 (instead of the 90mm). Andre
-- Andre Noble (email@example.com), March 05, 2001.
Sorry I can't help you with specifics about the Ebony bellows, maybe it will do what you need. I do leave the bag bellows on when I use the 180 and have no problems, so I don't have to switch in the field all that often. On the other matter it is true that a 45 on the 6x7 is wider than the 90 on 4x5, I think a 75 would be closer. 90 is a very useful focal length though, I use it quite a bit.
-- Erik Gould (firstname.lastname@example.org), March 06, 2001.