I am considering the #5 with the prism.
I have some problems in getting the correct focus in low light conditions.
Have anyone tried it?
Will it affect center point AF?
Read something on light measuring on lenses with f/4 and 5.6
That you get the wrong reading by 4 steps!
Will this also be the same on f/2.8 lenses, if you use f/4 or smaller?


