Just wondering if someone has a good conversion method to convert "New Zeiss" aperture sizes to today's standard system.
Just wondering if someone has a good conversion method to convert "New Zeiss" aperture sizes to today's standard system.
Thanks much. I've seen that one. What I'm wondering is whether anyone has mapped the number from say 27.36 to the nearest third or half stop between f/22 and f.32.
f 27.36 isn't a particularly useful number when using a meter calibrated in 1/3 stops
If you know the f-number, then take the next lowest standard f-number and use this formula to find the increment in fractional stops:
increment = log [ (f-number / next-lowest-f)^2 ] / log(2)
The amount of light goes as the square of the f-number, and every stop multiplies by a factor of 2 so stops are logarithmic.
For ex, I read that table as saying new-Zeiss aperture 4 = f/25, so compare it to f/22:
increment = log [ (25/22)^2 ] / log(2) = 0.37
So f/25 is about 1/3rd stop slower than f/22.
Another example of non standardisation to keep early photography difficult and secretive
and the beat goes on
Tin Can
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