An 80 mm lens will focus at 80mm regardless of what the film size is. A normal lens for 6x6 format is about 80mm which will produce roughly the equivalent view as a 50mm lens on 35mm. A 300mm lens will work like a 300mm lens, which, on a 4x5 negative will give you the same perspective as about a 85mm lens in 35mm, but when uses with a 35mm format it will be a 300mm lens. There are equivalent charts for lens length verses format at B&H's home page in the large format section and on several large format user pages on the web. Remember that a lens of some focal length will always produce the same image size, we just select how much of that image we want to see by how big a piece of film we put behind it. I looked into the Horseman view camera converter some time ago as an alternate to a Nikkor PC lens, a Zoerk panorama shift adapter or a real live view camera. There were several questions that I was not satisfied with about the Horseman or the Zoerk. It would appear that infinity focus is not possible with some of these adapters rendering it useless for my needs. To gain a wide angle perspective for architecture I would need a 28 - 35mm lens. These lenses for medium format cameras are not readily available in the used market and very expensive. New, these lenses can be $1500 or more. The Zoerk uses a medium format lens which has a longer mounting flange to film distance than 35mm cameras so they build the shift mechanism between the 35mm body and the lens mount to make it match the correct distance. I was not able to get any one from Horseman or Zoerk to adequately answer the questions about how much shift or tilt could be acheived before the limitation of the lens mount and camera body was reached. The Nikkor PC lens has a limited capability for shift and has no tilt capability. My decision, with input from many of the contributors on this list (thanks), was to buy a view camera. I found an Omega (Toyo) 45E in good shape for $400 with 2 flat and one recessed lensboard. I got a good 120 roll film holder and a handful of 4x5 film holders at a flea market. The lens is where I splurged and bought a new Grandagon-N 90mm F6.8 (I of course would have preferred a Schneider but the 90mm F8 has been criticized by many users and I couldn't stomach the cost of the F5.6 despite name brand loyalty). I have just started using this setup in the last week and will report more on my findings. I can report that I sorely miss the ease of use and portability of my bag full of Nikons but my initial feel is this is the solution to the results I was looking for.
