Ole said:
I blame Andrew (dagor77) for that too! On the other hand he's doing wonders to make Tessar lenses cheap - not "affordable", but cheap. Cheaper than a shutter alone
I am probably more to blame than dagor77 for the rise in price of the Computar lenses because of a couple of threads I started on the large format forum last year and earlier this year. However, I am glad that I did because prior to that there was a fellow buying the 210mm version of this lens for almost nothing and selling it for around $2000, which was about 10X the going price before I reported the results of my testing on the two threads mentioned above. I think he is now asking about $3000 for the 305mm Computar.
The Computar line (and by the way, some (but only a few) Kowa Graphics in 240mm and 270mm focal lengths have the same design) is a lens that was manufactured and sold in the late 70s and early 80s. It is a single-coated plasmat design that is certainly no optical match in terms of sharpness and contrast of the latest generation of lenses from Schneider, Rodenstock, etc. However, for LF and ULF formats these lenses are unique among small plasmats in that they have a circle of illumination of about 95 degrees (that is *ten (10)* degrees more than Dagors) and *fifteen (15)* degrees more than G-Clarons. And they are very small lenses, of f/9 maximum aperture. The extraordinary coverage and small size makes these lenses very desirable for ULF work. They are in fact my most prized lenses, and I own at this time 210mm, 240mm, 270mm and 305mm specimens.
For coverage, here is what you get with the Computars, assuming of course that you stop down to f/45 or more, and are at infinity focus.
210mm Covers 11X14 (just) and slightly vignettes on 7X17
240mm Cover 11X14 and 7X17 with about two inches of movement. Should also just cover 8X20 but I have not actually verified this on a camera.
270mm Covers 8X20 with movements and just slightly vignettes on 12X20.
305mm Covers 12X20 with about two inches of movement.
So when you really look at the unique qualities of these lenses you shold understand why they are currently selling for such high prices. And add to that the fact that although not rare, they are far less common than Dagors and G-Clarons.
Sandy