selmerdave
TPF Noob!
Can anyone tell me how to calculate flash guide numbers for film speeds other than those provided in the table in the manual? My Pentax 360FGZ gives a table for ISO 100 and 400 film, but I use mostly 50, 64 and 160 film. Of course a lot of the time I use auto flash or TTL depending on the camera, but I would like to be able to use it manually as well. Thanks.
Dave
Dave