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

Started Mar 31, 2014 | Discussions thread
Anders W Forum Pro • Posts: 21,468
Re: What else is happening before the first curtain on E-M1?

Jim Salvas wrote:

Anders W wrote:

Jim Salvas wrote:

With the new update installed and the electronic first curtain shutter option enabled, there is clearly a click before the exposure. It's easy to hear at 1/4 second and something is visibly moving very fast if you're brave enough to fire it off with the lens removed and watch what happens.

What is that?


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 to the thing you see moving, does it look like it's shutter blades blocking the sensor or something else? What about shooting a video of the sequence with another camera and play it back frame by frame?

I seem to get the same sounds with the lens on or off. Of course, the intensity of the sounds is different when removed, but the sequence seems to sound the same.

And the EFCS option is not greyed out or something like that with the lens removed?

Looking into the sensor, I can see something wink across it just before the exposure, but it does not seem to be a shutter blade. The shutter curtain is actually pretty far forward from the sensor and this -- whatever it is -- seems to be almost on the sensor.

I am only guessing here, but it might be something moving to "cock" the second curtain.

I thought it might also be an optical illusion caused by movement of the sensor as IS kicked in, but it's the same with or without IS.

Well that's another possibility that is worth considering. And setting IBIS on versus off doesn't offer a proper test. Even when off, IBIS behaves differently during exposure than before and after exposure. During exposure, regardless of whether IBIS is on or off, it goes into high-power mode (sensor held rigidly). Before and after exposure, it is in low-power mode (lower power consumption, less of the "fanning" noise).

When IBIS is on, it also goes into high-power mode when you half-press the shutter button provided that you have the camera set to stabilize the EVF on half-press. With the camera set to stabilize the EVF, do you see a difference in behavior when looking at shutter action if you half-press, wait a little, and then press fully versus pressing fully in one go?

Next step might be high speed photography of this happening. Wish I had that new Olympus compact, with 120fps.

Yes, it's hard to tell how much of it you can really see with ordinary video.

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