Quote:
Originally Posted by Don Hoey
Alex,
If you have a polariser that will cut 2 stops so you are nearly there.
Don
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... but if you have two polarisers you have complete control and the ability to shut it down to almost complete darkness.
Here's how it works:
Light travels in waves like ~~~~ A polarising filter works like a grid and only lets waves through that are the right way round like = or ||. So, if you have two turned at 90 degree angles you stop light no matter which way round it is.
This means you have variable control in all light conditions, just turn one of the polarisers to get from a minimum of 4 stops to pitch black.