burkphoto wrote:
E.L., you're old enough to remember the transition from Kodak Vericolor II to Vericolor III. That was when they switched from ASA to ISO on color negative film.
When Vericolor III came out, the box was marked ISO 160. But the 35mm and 46mm long roll films acted like Vericolor II, which was ASA 100. The 70mm long roll film with Estar base acted like it was ASA 80!
Kodak made up all kinds of excuses for what we were seeing (no shadow details and very dull highlights when the exposure was set based on a box speed of ISO 160), even stating some arcane math dealing with gamma and vagaries of slope calculations for shadow details.
Net result, as a lab, we told our customers to rate it at ISO 80 for 70mm, ISO 100 for 35 and 46mm long roll, and ISO 125 for 120/220/35 Perf. Then the 21-step gray scale Q13/Q14 chart looked as it had with Vericolor II!
Film or digital, whatever you use, MAKE TESTS to determine what works with your cameras, lenses, and processing. Results can vary a lot by serial number, make, model, and wear.
E.L., you're old enough to remember the transition... (
show quote)
As Im recall some films (dont remember which) had an ASA of 32. But most film cameras did not have such prcise settings. My Canon F1 ASA settings were 25, 50, 100 etc. So I shot it as if it had an ASA of 25. ( Panatomic X comes to mind)