neutral density filters: how many stops for daylight?

B

BrettR.

Active member
If I'm shooting at a normal shutter (180degree or whatever is the closest on a 7d) in normal daylight at iso 100, what strength neutral density filter do I need to compensate? If you know that much, what strength to get to f4 and to f11? I'd say 2.8 but my first lens isnt gonna be that good.

Thanks.
 
Going by sunny f/16 rule, you'll need 6 stops of ND to use f/4 with 1/48 shutter at ISO100. However, why ISO100? You'll have more dynamic range at ISO200 which is the base ISO for the 7D. I guess it will require even more ND at ISO200 so its your choice.
 
Well, 160 is the lowest native iso, so I'd probably go with that.

These two pieces of information will help you answer your question.

.3 = 1 stop
.6 = 2 stops
.9 = 3 stops

Every .3 is another stop...

The sunny 16 rule states that at f16, your shutter speed will be the inverse of your film speed. So at f16, if you were shooting at iso 64, your shutter speed would be 1/64th of a second. You have a round a bit because film speeds and shutter speeds don't match up exactly, but it gives you a very good idea of where your exposure should be.

So now, just do a bit of math and you can figure it all out.
 
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