Why shutter speed doesn't effect flash exposure

I can’t believe it took me two months to realized why you can adjust the exposure given by a normal light source with shutter, aperture and/or ISO, but why shutter speed doesn’t effect flash the same way… I was balancing flash inside a room against noon sun streaming in through the windows. Of course TTL wasn’t working…

DSC_3323.jpg

If you don’t know, it’s because the exposure given by the shutter is the acumulation of light over the entire duration, however the flash fires SO fast the entire pulse fits in. So adjusting from 1/30 to 1/200 doesn’t do squat, because the entire flash pulse may have fired in the first 1/20,000 and the rest of the frame exposes as normal so the full exposuire provided by the flash is given regardless.

As you can see it’s clearly possible to learn something about photography without taking a good picture while doing it.

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