View Full Version : Metering with odd aperture lenses

Noah B
2-Jun-2011, 17:31
Hello all, I currently own an f/9 lens and was wondering how you fellow photographers meter such lenses with maximum apertures such as this and 12.5 etc.? Currently am using a sekonic 308s meter.

Mark Sawyer
2-Jun-2011, 23:00
Consider what your meter tells you about the appropriate f/stop; the 308 gives tenths of an f/stop increments towards a set shutter speed or flash exposure. The indicated f/stop statistically only hits the exact even f/stop a tenth of the time.

A half-stop error seldom sinks a negative. And many (most?) shutters are off by half a shutter speed or more.

Doremus Scudder
3-Jun-2011, 00:54
I'm not sure I understand your problem.

My f/9 lenses all have standard aperture scales on them, i.e., the next full stop indicated is f/11, then f/16 etc. And, they are subdivided into 1/3-stop increments, which corresponds to the 1/3-stop increments on my meter. Just set the appropriate stop as indicated by your meter and you're good to go.

If you are shooting wide-open, then just remember that f/9 is approximately 1/3-stop down from f/8.

Are you metering with a metering back? A regular meter? Does it read in 1/3-stops or 1/10-stops?

Now, if you are shooting lenses with non-standard aperture scales (i.e., vintage lenses), you need to find which system your lens uses and make yourself a conversion scale so you can use your meter. Do some searching on non-standard aperture scales and you'll find what you need.


Doremus Scudder

Dan Fromm
3-Jun-2011, 05:06
Noah, you're not the first person to have had difficulty thinking about odd aperture settings. Have you considered getting a dead Weston Master IV or V meter not to have fixed and use but for its calculator? It will translate readings from y'r Sekonic to settings that fall between the Sekonic's steps.