Re: Thoughts on Electronic vs Mechanical shutter?

[Bill]

On 12/28/2016 11:28 AM, John Francis wrote:


I think you have that backwards.

With an electronic shutter, the image is taken at electronic speeds; the
entire sensor is cleared, then the image is captured.  There's no reason
for the electronics to expose different pixels at different times. While
there will certainly be some delay across the sensor, I would expect all
the pixel exposures to be synchronized to within a nanosecond, which is
effectively simultaneous as far as any mechanical system is concerned.



The electronic shutter in the Fuji X-T1 takes about 1/30th of a second 
to read the entire frame. I expect the Pentax is similar.


What you are talking about is a global shutter, not a rolling shutter. 
I'm quite certain that Pentax uses a rolling shutter.




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Re: Thoughts on Electronic vs Mechanical shutter?

[John Francis]

I think you have that backwards.

With an electronic shutter, the image is taken at electronic speeds; the
entire sensor is cleared, then the image is captured.  There's no reason
for the electronics to expose different pixels at different times. While
there will certainly be some delay across the sensor, I would expect all
the pixel exposures to be synchronized to within a nanosecond, which is
effectively simultaneous as far as any mechanical system is concerned.

With a mechanical shutter, however, you're not going to get that. There
will be a difference in time between the top and bottom of an exposure
frame, because the opening and closing of the shutter is controlled by the
movement of the shutter blind across the sensor. To a first approximation
the difference in time is the maximum flash synchronisation exposure speed
(not using high-speed flash, of course). Even if you have a camera capable
of flash synchronisation at 1/1000 of a second, thats still six orders of
magnitude more temporal distortion artifacts than from an electronic shutter.

while electronic shutters can expose all the pixels simultaneously, they
only read out the pixels sequentially.  But that's because of bandwidth
limitations (both within the sensor chip and in the interface to the camera),
not because the pixels are being exposed at different times.


On Wed, Dec 28, 2016 at 12:51:28AM -0800, Larry Colen wrote:
> I was playing with some night landscape work tonight, using live view, and
> when I took a photo, I didn't hear the shutter.  I realized that was because
> I had set my camera to use electronic shutter in live view because that
> means it doesn't need to go flop flop with the shutter and you don't get all
> of the shutter lag.
> 
> I realize that with objects in motion, using an electronic, or rolling,
> shutter, you can get some interesting bits of distortion.  However, it seems
> to me that on very long exposures, that effect is minimized, and you are
> saved a whole bunch of mirror bounce.
> 
> Are there any major disadvantages of using live view/electronic shutter, on
> tripod mounted long exposures that I'm missing?
> 
> -- 
> Larry Colen  l...@red4est.com (postbox on min4est) http://red4est.com/lrc
> 
> 
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Re: Thoughts on Electronic vs Mechanical shutter?

[Zos Xavius]

You don't see the rolling effect because it is only a half electronic
shutter. When the shutter closes or stops as an electronic aperture
does is when you get the motion artifacts. That's when the sensor
starts reading out. With a mechanical shutter it just closes and
starts reading off the sensor. With electronic it reads the sensor in
chunks. First curtain is possibly going to have more noise, but
probably not really since you are already in live view and the sensor
is active. If anything the electronic shutter might help with
vibrations. I don't see any major disadvantage there really.

On Wed, Dec 28, 2016 at 3:51 AM, Larry Colen  wrote:
> I was playing with some night landscape work tonight, using live view, and
> when I took a photo, I didn't hear the shutter.  I realized that was because
> I had set my camera to use electronic shutter in live view because that
> means it doesn't need to go flop flop with the shutter and you don't get all
> of the shutter lag.
>
> I realize that with objects in motion, using an electronic, or rolling,
> shutter, you can get some interesting bits of distortion.  However, it seems
> to me that on very long exposures, that effect is minimized, and you are
> saved a whole bunch of mirror bounce.
>
> Are there any major disadvantages of using live view/electronic shutter, on
> tripod mounted long exposures that I'm missing?
>
> --
> Larry Colen  l...@red4est.com (postbox on min4est) http://red4est.com/lrc
>
>
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> PDML Pentax-Discuss Mail List
> PDML@pdml.net
> http://pdml.net/mailman/listinfo/pdml_pdml.net
> to UNSUBSCRIBE from the PDML, please visit the link directly above and
> follow the directions.

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Thoughts on Electronic vs Mechanical shutter?

[Larry Colen]

I was playing with some night landscape work tonight, using live view, 
and when I took a photo, I didn't hear the shutter.  I realized that was 
because I had set my camera to use electronic shutter in live view 
because that means it doesn't need to go flop flop with the shutter and 
you don't get all of the shutter lag.


I realize that with objects in motion, using an electronic, or rolling, 
shutter, you can get some interesting bits of distortion.  However, it 
seems to me that on very long exposures, that effect is minimized, and 
you are saved a whole bunch of mirror bounce.


Are there any major disadvantages of using live view/electronic shutter, 
on tripod mounted long exposures that I'm missing?


--
Larry Colen  l...@red4est.com (postbox on min4est) http://red4est.com/lrc


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