What else is happening before the first curtain on E-M1?

Started Mar 31, 2014 | Discussions thread
Anders W Forum Pro • Posts: 21,466
Re: What else is happening before the first curtain on E-M1?

kenw wrote:

Anders W wrote:

Did you verify that the EFCS stays enabled (based on what the camera is telling you) when you remove the lens? One question we were pondering in the other thread was whether EFCS would be allowed/would work with a lens that is not electrically connected to the body. It may be that the EFCS needs/wants information from the lens in order to sync properly with the second curtain, or rather the shadow of the second curtain, which will vary with the lens, FL, and f-stop used.

As a related side note the GM1 has EFCS and electronic rolling as the only two options. When you put a manual lens on (no electronics) it always uses electronic rolling unless you are using flash.

That's very useful info. It suggests that the electrically connected lenses do have information about the parameters the body needs to calculate the movement of the shadow (rather than the curtain itself). With flash, of course, it doesn't matter (or doesn't matter as much) whether the two curtains are in perfect synch or not.

That would seem to match your stated theory about EFCS syncing and lens characteristics.


That said, it seems the EM1 only uses EFCS slower than 1/320 to begin with and I have trouble imagining the exit pupil location and size would really make a difference at what is effectively already the flash sync speed. I mean what will that be, 1/10th a stop variation?

Yes, my thoughts parallel yours exactly. It shouldn't make a whole lot of difference at the shutter speeds where the E-M1 uses the EFCS.

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