Dear /p/.I really need some advanced help.I've done some testing in a situation, and I can shoot the shot I want on f11 in 16 seconds, right exposure.However, I want to have a 13 minute exposure at f22 to get the desired effect. I have 3 ND 4x filters I can work with. How can I achieve the 13 minute exposure?
an hero
If its a Canon EOS - buy the cheap-ass remote, switch to manual, exposure time "bulb" , pressing the remote once opens the shutter, second time closes it
>>97678Practically any camera has a bulb setting. But that doesn't mean I'll get a correct exposure, right? I'm going the remote+B way anyhow. I just need to now how many filters to use to get the correct exposure at 13min.
Oh, wanted to add, this is on film. If it were digital I'd just try and try, but my amount of time and film is limited.
15s@f11 == 30s@f16 == 1m@f22 == 2m@f22+1stop == 4m@f22+2stop == 8m@f22+3stop == 16m@f22+4stopnow ND 4x filter requires 2 stop compensation so if you use 2 filters you get 4 stops.if my math is correct you need 2 filters ... now somebody correct me if a missed something
>>97691If I stepped down to f16, would I be able to get the 13 minutes more precise?
no cos otherwise youd just end up with:30s@f16 == 1m@f22 == 2m@f22+1stop == 4m@f22+2stop == 8m@f22+3stop == 16m@f22+4stopthe only way to change it properly is adjust the light levels.whats taking exactly 13 minutes anyway?
>>97700I'm going for 2 filters at f5.6, due to Reciprocity Time Failure (Someone else pointed that out for me.)It'll take 13 minutes for something to pass the lens.