hi i am selling a 270mm f9 computar lens, in a copal # shutter....the scale is a plastic overlay i measured right off the barrel of the lens...[which is also included].....to my knowledge, this is the widest modern lens to cover 12x20...as it just "hits the cornerns" on 12x20.... 591ic f45.......Sandy King has remarked , in other forums , on the sharpness and extreme coverage of the computar lenses...also, the computar lenses were renamed kyvytar ...and then kowa... but some of the designs changed as well....so the only sure way of getting the promised coverage is to buy the computar branded lens...........the only other 270 computar i've seen sold for 1800.00 about 4 years ago.....given the downturn, i'm pricing this one at 1150.00...shipping and ins extra..i'll take the paypal hit... thanks g