S110, half of the images are overexposed, can it be fixed? - Hotwire! Hardware Mods, Accessories and Insights - CHDK Forum

S110, half of the images are overexposed, can it be fixed?

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Offline Mlapse

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S110, half of the images are overexposed, can it be fixed?
« on: 13 / November / 2023, 09:26:03 »
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One of my S110 has developed a problem that i have never seen before.
about the bottom half of each picture is overexposed, everything else seems as intended.

compared with another s110, they do the same exposure side by side, so why one half of the image ends up overexposed is a puzzle to me.

the cam has been used upside down for the better part of a year and that's something i've never done before....i hope that's not related.

Normally i would just get another one, but my last spare is now active and since they are of 2012, it's becoming harder to find them.
If possible i will take a go at repairing it.
« Last Edit: 15 / November / 2023, 03:26:16 by Mlapse »
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Offline reyalp

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Re: S110, half of the images are overexposed, can it be fixed?
« Reply #1 on: 13 / November / 2023, 13:11:25 »
That's pretty weird.

Does the live view look normal? Do long exposures (like 1+ second taken in low enough light to need it) look the same?
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Offline Mlapse

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Re: S110, half of the images are overexposed, can it be fixed?
« Reply #2 on: 13 / November / 2023, 14:14:32 »
The live view looks normal, also low light images (< 1/30) seem normal, longer than 1 seconds also good. as far a i can see it only happens with daylight.
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Offline reyalp

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Re: S110, half of the images are overexposed, can it be fixed?
« Reply #3 on: 13 / November / 2023, 17:33:11 »
The live view looks normal, also low light images (< 1/30) seem normal, longer than 1 seconds also good. as far a i can see it only happens with daylight.
My semi-educated guess: Some kind of problem with the mechanical shutter, either not closing completely or maybe not moving at expected speed. Live view doesn't use it, and with long exposures, the amount of additional light collected during readout when the shutter is supposed to be closed will be relatively insignificant. I guess in this case short exposure with flash (in an otherwise dark scene) should also probably come out fairly normal.

My other thought was you could get an effect like that with the ND stuck half way, but that would obviously affect live view and not vary with shutter speed. Any sort of sensor electrical problem would also seem likely to affect long exposures and/or shutterless operation.

Software issues seem extremely unlikely, but you may as well run the firmware CRC check in Miscellaneous -> Tools -> Checksum ROM

Hard to imagine any fix that doesn't involve disassembly or replacement, but I guess you wouldn't lose much attempting percussive maintenance, perhaps in combination with the hammer the shutter script.
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Normally i would just get another one, but my last spare is now active and since they are of 2012, it's becoming harder to find them.
If you have other cameras that died in a different way, could try a transplant. Or perhaps find an otherwise dead one on ebay or whatever.
Don't forget what the H stands for.

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Offline Mlapse

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Re: S110, half of the images are overexposed, can it be fixed?
« Reply #4 on: 14 / November / 2023, 03:09:12 »
My semi-educated guess: Some kind of problem with the mechanical shutter, either not closing completely or maybe not moving at expected speed. Live view doesn't use it, and with long exposures, the amount of additional light collected during readout when the shutter is supposed to be closed will be relatively insignificant. I guess in this case short exposure with flash (in an otherwise dark scene) should also probably come out fairly normal.
That is what i thought of first.
The big question for me is, does the s110 have a 'guillotine' shutter that drops down, like f.i. the M series?
correction, i would think it's actuated with a rotating arm to close the shutter looking at how it's overexposed...not just halfway, but the overexposed area runs a bit down to the right bottom corner.
in that case my spare in it's upside down position will probably die too because of fighting gravity when it closes the shutter, rotating/sliding upwards instead of down.
redesigning the rig could solve that if this is the issue.

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My other thought was you could get an effect like that with the ND stuck half way, but that would obviously affect live view and not vary with shutter speed. Any sort of sensor electrical problem would also seem likely to affect long exposures and/or shutterless operation.
Although ND is always off in my setup i tried toggling that and you hear the click and see the live view blink, but found no difference.

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Software issues seem extremely unlikely, but you may as well run the firmware CRC check in Miscellaneous -> Tools -> Checksum ROM
i would think that is highly unlikely too, my thought was maybe corroded contact, but with poor electrics i would expect the images to be darker.

nonetheless should that give any feedback if all is ok? because i ran crc check but after the rom crc file/time indicator ran out nothing appeared on screen or sd card.

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Hard to imagine any fix that doesn't involve disassembly or replacement, but I guess you wouldn't lose much attempting percussive maintenance, perhaps in combination with the hammer the shutter script.

will try this later...and percussive maintenance....i never thought banging your equipment had a name other than 'abuse' :) did fix one of my s95 stuck shutter in the past, i haven't had luck with this cam yet.

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If you have other cameras that died in a different way, could try a transplant. Or perhaps find an otherwise dead one on ebay or whatever.

i haven't kept my dead cams since i never considered repairing them.
aside from making a new rig, moving to the g7x would be too much an increase in data and processing time to do that with my current setup and equipment.

so i think it's getting to the point where this long running project will end with the next cam failure....especially if the failure has to do with the cam being upside down.
« Last Edit: 14 / November / 2023, 05:08:25 by Mlapse »
frustration is a key ingredient in progress

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Offline c_joerg

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Re: S110, half of the images are overexposed, can it be fixed?
« Reply #5 on: 14 / November / 2023, 07:19:38 »
That is what i thought of first.
The big question for me is, does the s110 have a 'guillotine' shutter that drops down, like f.i. the M series?

Like all Powershots, the S110 has a central shutter. You can also see this by the short flash syncronization time.

 

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Offline Mlapse

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Re: S110, half of the images are overexposed, can it be fixed?
« Reply #6 on: 14 / November / 2023, 07:54:16 »
Like all Powershots, the S110 has a central shutter. You can also see this by the short flash syncronization time.

well, that rules at least out that it is related to the fact that the cam was hanging upside down.

and it is also a bit incompatible with a stuck shutter if it doesn't move from top to bottom, since only the bottom half of the frame is overexposed and not the center part as i would imagine to be the case with a slow leaf shutter.

and it would also explain why it wasn't solved by banging on the cam and shooting 1500 images the right way up ;)
« Last Edit: 14 / November / 2023, 08:00:50 by Mlapse »
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Offline c_joerg

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Re: S110, half of the images are overexposed, can it be fixed?
« Reply #7 on: 14 / November / 2023, 11:48:17 »
I think the shutter is not closed properly and lets some light through. The sensor is read in the dark. The lines that are read out at the end are then too bright. I would take a photo of a white wall and look at the progression of the brightness.
M100 100a, M3 121a, G9x II (1.00c), 2*G1x (101a,100e), S110 (103a), SX50 (100c), SX230 (101a), S45,
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Offline reyalp

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Re: S110, half of the images are overexposed, can it be fixed?
« Reply #8 on: 14 / November / 2023, 12:40:59 »
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Software issues seem extremely unlikely, but you may as well run the firmware CRC check in Miscellaneous -> Tools -> Checksum ROM
nonetheless should that give any feedback if all is ok? because i ran crc check but after the rom crc file/time indicator ran out nothing appeared on screen or sd card.
That's the expected behavior if no errors are found.

I think the shutter is not closed properly and lets some light through. The sensor is read in the dark. The lines that are read out at the end are then too bright. I would take a photo of a white wall and look at the progression of the brightness.
Agree, that seems like it fits, and a uniform scene would definitely make it easier to see what's going on.
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Offline Mlapse

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Re: S110, half of the images are overexposed, can it be fixed?
« Reply #9 on: 14 / November / 2023, 15:01:42 »
it's not a white wall, but i think it'll suffice to show the result.

these are 2 pictures, shot side by side at the same day, moment and settings.
so you have a reference of the sky.

could this really be caused by some defect in the leaf shutter?
« Last Edit: 14 / November / 2023, 15:03:53 by Mlapse »
frustration is a key ingredient in progress

 

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