Help with filters, please.
Going through the filters that came down to my with my Dad's Contax IIIa, I find a UV filter, a Y2, an R1, a blue one marked FLASH, a brownish one marked "daylight A" and an orange one marked YA3. My questions are these: How much more exposure do I allow for the R1? What does the YA3 do and how much extra exposure? And just out of curiosity; What do the "daylight A" and the "FLASH" ones do? I'd only use the ones for black and white.