photosailor
17-Mar-2010, 18:04
I got a Wollensak f4.5 241mm Raptar with an 8x10 view camera I bought a while ago. It wasn't mounted on a lens board and hadn't been used with the camera, just something thrown in with the deal. The Alphax shutter has three f-stop scales, but none matches the f/4.5 marked on the lens (one starts at f/7). I got to thinking that creating a scale for this lens couldn't be too difficult: just measure the diameter of an iris opening and divide by 241--bingo! the f-stop.
I measured 32mm when the scale read f/8; doing the math that is .1327 and f/8 is .125 so it seems that my simplistic formula is right. Except that f/8 was on the scale that starts at f/7.
So my question is: is the f4.5 Raptar maximum aperature f/7 when mounted in Alphax shutter and should I be using that scale? I haven't had the shutter CLA'd so I don't know how accurate the speeds are so I can't interpolate the f-stop from a correctly exposed negative.
Amazingly, this lens seems to cover nicely the 8x10 format.
Any observations you have about this lens will be appreciated. Thanks!
I measured 32mm when the scale read f/8; doing the math that is .1327 and f/8 is .125 so it seems that my simplistic formula is right. Except that f/8 was on the scale that starts at f/7.
So my question is: is the f4.5 Raptar maximum aperature f/7 when mounted in Alphax shutter and should I be using that scale? I haven't had the shutter CLA'd so I don't know how accurate the speeds are so I can't interpolate the f-stop from a correctly exposed negative.
Amazingly, this lens seems to cover nicely the 8x10 format.
Any observations you have about this lens will be appreciated. Thanks!