exposure factor:
x=(m+1)*(m+1)
"m" is an enlargement
The enlargement you can count by means of the some ruler.
object = 50mm
image (on film) = 25mm
exposure factor x = (0,5+1)*(0,5+1) = 1,5*1,5 = 2,25x
you add 1 diaphragm number (e.g. from 5,6 on 4)
All is okay?
van

piterengel napsal(a):
Hi, I'm waiting for the arriving of a Zenzanon macro lens, I've
ordered it and soon it will be here. I have a question. Because I've
not an AE prism finder, how can I calculate the right exposure when
lens is completely extended to have the maximum macro efffect? Are
there tables for this?
Thanks all