What's the difference between these lenses? After seeing tons of sample photos and rave reviews here, I'm very interested in getting myself a Rokkor X 58mm 1.2. I've seen some Rokkor PG's for sale? What's the difference? Which is THE lens to get? Thanks for the help.
The "X" is meaningless with respect to the lens design. It was simply added to some of the lenses depending on what market they were destined for. Sort of like how the "Digital Rebel" is a "300D" in some markets and a "Kiss Digital" in others.
The "PG" simply indicates the number of elements/groups in the lens design. In this respect they are all the same, regardless of whether it says "PG" or not.
If you end up getting one and you have any questions about the conversion, etc. or even if you'd like to share some shots, be sure to drop by http://forum.cogitech.ca/
My experience with MC 58/1.2 lenses is the markedly warmer color shift of the early lenses with metal focus rings. Although apparently completely reversible with a UV light treatment, it is surprising to see the difference, and requires an effort to bring the warm color back to neutral. This warmness is related to glasss discoloration of the higher refractive index , of the glass containing rare earth elements and can emit radioactivity.
So far, I have seen a very consistent, equivalent, infinity sharpness between all of them. Just to qualify, infinity focus is very absolute. There is no sharpness question, due to focus accuracy, as there is on short and medium distance tests. Lastly, all my observations are comparative. I have a reference lens, and sometimes 2 other lenses to compare, at the same time of day, same exposure, etc.
