Thanks for the explanation of the operation of an eShutter. I had
assumed (wrongly) that an eShutter fully exposed the sensor to light for
the full duration of the exposure, then shut off and began a sequential
read from the stored pixel values. I never understood why the Minolta
A1 has both an eShutter and a mechanical shutter. I suppose flash synch
is the answer.
Chuck Norcutt
On 12/8/2013 12:04 AM, Moose wrote:
> Another misunderstanding. The eShutter is like a focal plane shutter on an
> old Speed Graphic. It records a band of image
> that moves quite slowly across the image area. That's why no flash sync with
> it.
>
> Although it's not certain what this speed is on the GX7, it is about 1/10 sec
> on the GH3. It may be a bit faster than
> that, or not. So, at any speed over about 1/10, the electronic 'slit' will be
> traveling across the image area, and
> variations of brightness will tend to show up as banding. I seem to recall
> something that could lead one to conclude
> that it has been sped up a bit on the GX7. If so, 1/15 to 1/30 may well work.
>
> It's quite different with a mechanical shutter, because the curtains travel
> so much faster. There, at anything less than
> the flash sync speed, the shutter is completely open for a time. At slower
> speeds, like 1/30 and 1/60, it is fully open
> for most of the exposure period, and you are correct.
>
> So banding is a risk with other than incandescent light, even at 1/30,
> although the manual says slower is better. I also
> believe I've read that there tends to be less trouble at 60 cps than at 50. I
> don't know any thing to do but test under
> the lighting in question. A quick test early on should reveal how it works in
> any given light.
--
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