Anyone having this problem with the Sony A7? black area of image.

Started 2 months ago | Discussions thread
verybiglebowski
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Re: Anyone having this problem with the Sony A7? black area of image.
In reply to SQLGuy, 2 months ago

SQLGuy wrote:

sybersitizen wrote:

SQLGuy wrote:

... But, as I mentioned a couple of months ago in the other thread that was linked, I don't think they are talking about the shutter curtain causing the issue - I think they are saying that the camera won't always get the aperture set to the selected value before starting the exposure. If the iris is closing while the shutter is firing, that will result in "uneven" brightness.

That doesn't help explain the phenomenon, because it would result in overexposure of the part of the frame that gets exposed first - and because of the upward-moving shutter, that's the bottom of the camera (which, because of the inverted image created by the lens, ends up being the top part of the photo in normal landscape orientation). But the result we see is the opposite effect: underexposure.

Yes. I know. That's what I was saying: that the line from the manual does not suggest the behavior the OP is seeing.

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A7 with kit lens and a number of legacy lenses (mostly Canon FD); A3000 converted to IR.

This phenomenon has nothing to do with legacy, telephoto or WA lens. It is related to high shutter speed. Electronic first curtain has to discharge sensor pixels (switch them off) before they are switched back on, in order  to start the exposure and prior to mechanical shutter that follows closely (at high shutter speeds) will end exposure.

This process of discharging pixels is not instanious, it takes row by row pixel discharging. Idea is, that pixel draining itself (that starts the exposure right afterward) copy the speed of mechanical shutter.

But at a higher shutter speed, EFC can't finish discharging pixels before the shutter starts to close, in order to end the exposure.. Thus part of the image (where mechanical shutter close before exposure even started, or where it started too late) remain darker (unproperly exposed).

Please note that this explanation is extreamy simplified, but I hope you got the idea.

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