Why only 1/1250s @ f2.8 on DP2 Merrill?

Started Apr 21, 2013 | Questions thread
Roland Karlsson Forum Pro • Posts: 26,250
Re: Why only 1/1250s @ f2.8 on DP2 Merrill?

PicOne wrote:

I know this is the answer... what I'm curious about is why shutter speeds of 1/4000 to 1/8000 etc.. aren't achievable with f/8 and smaller..   Ie. why does the Tv to Av relationship stop having an impact at f/5.6 ?

This is what it says in the user manual.

30s ~ 1/1250s : F2.8 ~ F16
1/1600s : F4.0 ~ F16
1/2000s : F5.6 ~ F16

Seems quite reasonable I think.

You have to remember that the diameter of the aperture is the sqrt of the area. So, if the shuttewr moves linear, then you need two stops to gian a stop in shutter speed. So ... then the max shutter speed (at F2.8) would be 1/4000. Now, I assume the movement is not linear, but much faster in the beginning and end to minimize the problem. Then you wont gain much.

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