I have a copy of the lens that Mark pointed to, and it is a very good lens. It is so good that you will probably not be able to fully exploit its qualities until you've got some considerable LF practice under your belt. That said, my only and very minor complaint with this lens is that it can be a bit too wide at times. I have a 203mm f/7.5 Graflex Optar (not supposed to be that good, but I'm not complaining) when I want a little tighter view. Truth is that when you're working with such a large negative, lens quality, unless it's truly bad, isn't nearly as important a factor as it is when working with smaller formats because you won't be enlarging the negative nearky as much.. If your goal is to make contact prints, you'll never see it. Anything up to 4x to 6x enlargements will be beautiful. Only when you get into far higher magnifications do the shortcomings of lesser lenses become obvious. So my advice to you is to find something in the 150 mm to 210 mm range that fits your budget as your starter lens. Avoid the true telephoto designs for the reasons already noted by previous posters. You won't be happy if you need to use movements. A convertible lens might be a fun thing to play around with, but be advised that the results will be a little bit soft when used with the the top down (one set of lens cells removed. Then again, it might not be enough to be of any real consequence. After all, photographers have been using them happily to make marvelous images for years.
Originally Posted by Mark Fisher