I have a 55mm Nikon macro lens, really neat older lens, and I would like to use it for plant and flower shots. I understand that there is some compensation factor needed for the macro end of the spectrum. What are some good references on this, or some rules of thumb? I plan to be using color transparencies. (Fuji).
If you're using the camera's TTL meter, then the compensation is automatic.
With a hand-held meter, you need to know (or approximate) the factors: I've stuck a piece of tape on my lens barrel next to the focusing scale with the factor written on it...
FYI:
At 0.6m (c. 1:9) the factor is 1.2
At 0.4m (1:5): 1.5
At 0.25m (1:2): 2.2
All the formulae involved, and how to use them can be found here.
(The page (the entire site it is on) is dedicated to another format film, but the calculations are the same.)