Quote Originally Posted by Jac@stafford.net View Post
Pere, excuse my confusion, please.
The OP wrote, in part,
[B]


And my mind went into 'what is reasonable' therefore presumed the unlikely success of a hand held one second exposure. I hope we are okay, Pere.

Best,
Jac
Oh, don't need to excuse... of course

Time ago I bought a cheap photocell type tester and I was very surprised that even my best shutter had remarkable differences from marked speeds, in fact a new shutter can have +/- 30% error and it is still under specs, so they can vary a full stop (1/40 to 1/80 for 1/60) even brand new. Mechanical shutters are not precise, fortunately they usually repeat same time, so a tester solves the thing.

I'm surprised about the fact that (in general) there is lot recommendations about modifiying film speed by say 1/2 stop while there are few warnings about checking shutters. I feel that in reality overexposing 1/2 stop is just a safety belt for the shutter variability. Overexposing negative film is not that bad, but one stop can ruin an slide... so Velvia likes shutter testers