Originally posted by thazooo Found a place selling it and they suggest set to lowest asa setting and subtract 5 stops. Then again I've got a Sekonic that should meter it
The issue I was getting at was more that Sunny 16 for this film falls in between two shutter speeds, and if you're shooting (for example) a Ricoh K-mount film camera (e.g. XR-1) there are no half stops on XR-series lenses (except on the full-open setting for the 50mm f/1.7, etc).
When in doubt, overexpose by half a stop, I guess. I have a battery-less Sekonic that goes down to 6 ASA, therefore two stops above that 1.6 ASA colour film, and anyone who shoots a film that slow is going to be taking things at a deliberate pace anyway.
Still, if you have an f/1.4 lens you get seven stops worth of opening, which makes 1.6 ASA hand-holdable in bright sunlight, and even f/2 lenses will manage that at a pinch. The camera whose fastest lens is an f/3.5 Asahi-Kogaku Tessar (I'm looking at you, Asahiflex) requires a much steadier hand at such low film speeds. For casual handheld work there, you need the blistering speed of Kodachrome 25.