View Full Version : Strange old aperture scale

Joakim Ahnfelt
4-Jun-2006, 12:48
I picked up an 9x12 cm folder of unknown age that came with a 135 mm "Rodenstock's Extra Rapid Aplanat 1:7.7". It's in a Vario shutter 25, 50, 100, B and T. Nothing strange with that but the aperture scale confuses me somewhat. It's 7.7, 9, 12.5, 18, 25 and 36. I've never seen this before on any old lens. How do I handle it? Just try to guesstimate the position of ordinary shutter numbers?

Ole Tjugen
4-Jun-2006, 13:21
That's one very common variation of the standard aperture scale. How you handle it is entirely up to you - the difference between f:8 and f:9 is about the same as between 1/50 and 1/60 second. And a good shutter will be within 20% of the correct time, but of course slightly dependent on the aperture setting.

Don't worry - it's close enough for most purposes. If you want to "guesstimate", do. You won't be far off.

It only gets really difficult when you find a lens with aperture scale in mm. I discovered last week that I have three of these...

Dan Fromm
4-Jun-2006, 13:38
Interpolate between the marked stops to get the one you want. The sequence is in whole stops, starting with f/9.

Brian Ellis
4-Jun-2006, 16:50
You have to love those old lens names. How could anyone fail to make great photographs with an Extra Rapid Aplanat on the camera?

Uli Mayer
5-Jun-2006, 23:58
This old scale is like a modern one - shifted by 1/3 stop.