Shadowy Daisy

Shadowy Daisy
by damned-truths

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I have a Canon PowerShot A470. One day, while taking photos, it has gone from taking perfect pictures to being massively overexposed (almost white) pictures; however, this is not a problem with taking videos - they are absolutely fine.

I have gone through all the settings that I can find (most importantly, changed the exposure done to as low as possible - no help). Does anyone have any suggestions, or is something fundamentally broken?

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reset settings to factory default? (somewhere in the menu...). Check also the dial : are you not in "Bulb" mode ? (the dial can move unexpectedly...) – Olivier Dulac Mar 19 '14 at 15:24
    
I don't believe the A470 has a bulb mode :-) It's a very basic P&S. – Philip Kendall Mar 19 '14 at 15:59
    
@PhilipKendall indeed. But it could be set on "Scene" with some long exposure scene? or "Manual" (= semi-auto) with some weird setting? returning to "default" to test the camera would then be a good step. – Olivier Dulac Mar 19 '14 at 16:59
1  
I've tried resetting to default, changing the "scene", using auto, using manual and changing the exposure. I've tried taking a photo underneath tables / behind settees, which should be very dark, but the pictures are still bright (pretty good actually, considering!) - unfortunately, in normal light, they are mostly white! – Smiley Sam Mar 19 '14 at 23:15
1  
Because it's not using the mechanical shutter in video mode. It could be repairable (simply a stuck shutter lever) but who can be bothered dismantling a compact lens these days? – BBking Mar 25 '14 at 3:35

I probably know an answer.

Cameras almost always have aperture open if not recording anything - to make the optical viewfinder brighter or electronic viewfinder display better image.

Then, cameras close aperture for each exposure to arbitrary or automatically selected F value.

Cameras know how much light will be cut if they close down to F if they know the open objective speed.

Now, if the aperture is stuck in the middle, camera will always overexpose photos when set F is bigger than initial F, and will do so even more if the aperture does not move at all.

The video mode may be unaffected because in this mode camera meters in real time, just the noise may be bumped.

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Interesting idea. If it is the case, any idea how I'd fix it? =D – Smiley Sam Mar 25 at 18:32
    
@smiley-sam: you'd better check if it's the case - look into the objective and see whether aperture moves. If it does not move at all, you may be sure in that it is the case. What next? I would take it apart and see what is wrong. The technology is quite tough nowadays and most malfunctions are caused with small defects - like, big dust particle got somewhere into mechanics. – Euri Pinhollow Mar 25 at 18:37
    
@smiley-sam: or, the ribbon cable may be damaged, and that would be even easier to repair (give that you have a source for spares). – Euri Pinhollow Mar 25 at 18:57
    
Thanks. I'll have a look into that. Need to find the camera again first! =P – Smiley Sam Mar 27 at 7:48
    
@smiley-sam: it is sure worth it, at least for trying CHDK. You may as well remove IR mirror from there. – Euri Pinhollow Mar 27 at 8:51

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