Henning Koepke

The only mechanical shutter speed on the f3 is a 1/60. You can use it by pressing the Backup mechanical release lever (if you look down on the camera from behind) on the right front side to the right (no 6 in the instruction manual)

I have two F2's, one F2a (recently serviced by Sover Wong and with new cds cells) and one F2as. Both are calibrated equally on grey cards. But green makes a big difference: On my F2a a green plant is measured as f8 1/125s, on my F2as I measure f5.6 1/125s. I tried different situations, always the cds cells from the F2a measure 1 f-stop more light than the F2as. I compared it with my F3 and also with my F5. They are both equal to the F2as. Is it common, that cds cells have a bigger green sensivity?