f/ numbers, help please!

[6x6x9]

Hello!
I'm confused by the f numbers written on my Wollensak shutter (see the first two attached images). There is also a hand written scale on the camera's base plate (see the last attached file).
Which scale should I follow in order to get properly exposed negatives?
What does the last column of hand written scale means?
I know that I should test both scales and see which one gives better results, but I just want to clearly understand what I'm doing. Just to mention, I have Lunasix 3 light meter which mesures up to f/90.
Thank you!
snjesko

 

[StreetShooter]

I'd probably use the middle column numbers... but, round them out to the appropriate "modern day" apertures.

For example, on the lens is the figure 48. If you look at the left hand column in the scale, it looks to correspond to 21.9, which, rounded off, is equivalent to f22.

The figure 24 looks to correspond to 15.5, which, rounded off, is equivalent to f16.

Take the lens out and take some pictures premised on the above and see what turns out.

Caveat: This is just my best guess since I've not used one of these lenses before. But, I'll bet Jim Galli has and, perhaps, he'll jump in with some thoughts.

Good luck.

Cheers

 

[Ole]

Now that is a tricky one!

My first guess is that it's the US scale, where US 16 = f/16, and US 32 is f/22. The US scale doubles with each stop.

But the 24, 48, 96 progression is not the normal one for US - it looks more like a Stolze scale. (search here, I've described both Stolze and the "French system" before.)

Assuming it's US the US 12 is midway between 8 and 16, so that should be midway between f/11 and f/16.

I have no idea about the third column - sorry.

 

[BradS]

the focal length of the lens currently mounted in the shutter might provide a clue to this mystery. I'm gonna guess that the numbers engraved on the shutter were for a different set of cells than those currently installed. Somebody did the math to make the conversion. I'll further guess that the last column of numbers are the...eh, EV values for those f/ numbers....I think those would be the A's in the equation.... S + L = A + T in the Apex exposure system? (where S is for film speed, L is for light value, A is for aperature value and T is for shutter speed - time value).