File :-(, x, )
Anonymous !MjcMqTX/iM
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?
>> Anonymous
an hero
>> Half-Eye !Ir.x8Zkt3c
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
>> Anonymous !MjcMqTX/iM
>>97678
Practically 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.
>> Anonymous !MjcMqTX/iM
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.
>> Anonymous
15s@f11 == 30s@f16 == 1m@f22 == 2m@f22+1stop == 4m@f22+2stop == 8m@f22+3stop == 16m@f22+4stop

now 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
>> Anonymous !MjcMqTX/iM
>>97691
If I stepped down to f16, would I be able to get the 13 minutes more precise?
>> Anonymous
no cos otherwise youd just end up with:

30s@f16 == 1m@f22 == 2m@f22+1stop == 4m@f22+2stop == 8m@f22+3stop == 16m@f22+4stop

the only way to change it properly is adjust the light levels.
whats taking exactly 13 minutes anyway?
>> Anonymous !MjcMqTX/iM
>>97700
I'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.