What aperture is 2.8.2?

[Jerry Bodine]

To be a little more precise, a shutter’s speeds are accurate if they are +\- 30% of the marked speeds.

Shutter speed tolerances according to Flutot's Camera Repair are shown here.

[Bob Salomon]

Shutter speed tolerances according to Flutot's Camera Repair are shown here.

Since we were the Rollei, Minox, Linhof and Rodenstock distributor we didn’t use Carol, we used the various factories and they all stated 30%.

[Sal Santamaura]

...I have this meter and the little ON switch was always sliding on and battery dead. Then I taped the switch off and the battery still seems to die, so now I remove the battery and tape it to the bottom of the meter for when I need it...

Eric, even you couldn't get a Pocket Spot?

[Roger Beck]

Y’all are right, I’m not trying to be super accurate. I tend to round up a lot for exposure and yes, lens specs are rounded up or down, the real focal length, the true aperture. Just wondered why there were two standards for lenses. Still, would be handy to have a list of actual aperture size for reference in 1/10 stop increments.

[LabRat]

Y’all are right, I’m not trying to be super accurate. I tend to round up a lot for exposure and yes, lens specs are rounded up or down, the real focal length, the true aperture. Just wondered why there were two standards for lenses. Still, would be handy to have a list of actual aperture size for reference in 1/10 stop increments.

Not rocket science... 5/10's is a half stop, but for something critical like on the edge of a white background, 1/10 would not be seen by LF chrome film, but 2/10's would start to be visible... Between 3 and 4 10's is a third of a stop, so that's a guide for you...

Happy metering!!!

Steve K

[Roger Beck]

Not rocket science indeed. Here are the multiply factors to get the aperture in 1/10 of a stop. After that are are the common maximum apertures of older lenses, and their decimal equivalent.

.0414 - .1 stop
.082 - .2 stop
.1242 - .3 stop
.1656 - .4 stop
.207 - .5 stop
.2484 - .6 stop
.2898 - .7 stop
.3312 - .8 stop
.3726 - .9 stop
.414 - 1 stop

3.5 - 2.8/6
4.5 - 4/3
4.7 - 4/4
6.3 - 5.6/3
6.8 - 5.6/5
7.7 - 5.6/9
9 - 8/3
12.5 - 11/3