Kodak Flash Supermatic shutter question

[Lee Rust]

My Kodak Ektar 203mm is in a Flash Supermatic shutter. The highest marked f stop on the scale is 45, but the iris can stop down quite a bit further than that. Does anyone know what that unmarked smallest aperture might be?

Thanks.

[Jim Jones]

Mine might differ from yours, so measure the apparent diameter of the smallest aperture as it appears with your eye some distance from the front of the lens, and divide that figure into 203.

[Fotoguy20d]

if you don't have go/no-go gauges (not much reason for you to have them), you can also use any dowel of known size, or even something like a machine screw (carefully), to "measure" the opening. If you don't have a caliper, either a $2 plastic vernier from Sears or a $10 digital from Harbor Freight is a useful thing to own.

Dan

PS. I have a pair of these in Supermatic. I can measure mine tomorrow if you have no way to measure yours. If there's not a lot of variation in mine, you might assume yours is the same.

[Lee Rust]

Jim and Dan, thanks very much for your help. I do have a caliper and will do the math.

[Lee Rust]

Minimum opening is 2mm, so 203/2= f101.5. That's getting into pinhole territory.