Lens Coverage Specs

greenspun.com : LUSENET : Large format photography : One Thread

I am considering a move into LF Photography, but I'm having some trouble deciding which lens to start out with. I was considering a "kit" system, and most seem to come with a 135mm as a sort of standard. I've seen that the 135mm is a relatively WA, and would offer some versatility, and then I see in the "lens comparison chart" on this website that the lens will not adequately cover the [5x7] format. I also see that wider and longer lenses will?? This doesn't make sense to me. When I look at actual lens specs, the image circle grows pretty much directly in proportion with the focal lenth of the lens, as well it should. It also seems like cropping would be pretty routine in this format anyway, so why should coverage make that much difference? Anyone who could shed some light on this, and make this transition to "real" photography any easier for me would have my sincere thanks.

-- Phil Maus (Eros002@aol.com), December 12, 2001


Phil, it's simply a matter of lens design. Look at Schneider super- angulons, for instance. You can get a 90mm f5.6 S-A lens with an image circle of 216mm, but if you look at the same lens in the XL version, it gives you an ic of 259, but in a much larger design and for a much heftier price. I, too, wanted a lens in about the 135mm range, and picked up a Symmar-S 135mm f5.6 lens for $250 that turned out to be unbelievably sharp, but limiting in the image circle criteria. I gave that to a friend and picked up a Fuji 125mm lens that had a larger image circle, but instead of $250, it was $600. Look at image circle, angle of view, recommended max format. They'll tell you something about how the lens should best be used.

-- Todd Caudle (todd@skylinepress.com), December 12, 2001.

Phil - Your comment about cropping leads me to believe that you don't yet understand the need for "coverage" in LF. When using the versatility of LF tilts, shifts, rise and fall, the amount of coverage becomes very important. I suggest you start by studying a basic book on view camera movements such as Simmon's Using the View Camera. It will show you graphically why coverage is important and will also "show" you what the various terms used here mean. If you don't yet have a handle on the terminology you can make many expensive mistakes in your early purchases.

-- Bob Finley (Rfinbob@aol.com), December 12, 2001.

Moderation questions? read the FAQ