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Old Feb 19, 2007, 11:27 PM   #1
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Hi Folks,

I notice that my A100 is intermittently making a ‘whirring' sound on long time exposures. For you old timers the sound is reminiscent of the old all mechanical cameras.

Have any of you observed this with your cameras? Mine seems to be working okay but I'm wondering if a visit to the service depot is imminent.

Thanks for any input you may have.

--FrankD
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Old Feb 19, 2007, 11:44 PM   #2
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Yes. I have over 10,000 shots taken on mine and I noticed that noise the other day.
WHAT IS IT???

Worried.


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Old Feb 19, 2007, 11:51 PM   #3
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How long?

With any exposure of about 1 second or longer with noise reduction turned on, the camera will automatically take a second "dark frame" (shutter closed) photo that it uses to locate hot pixels and subtract them from the actual exposure.

Could the second exposure be what you're noticing after the shutter has been released? If not, it could be the AS. I'd compare your camera to another one in a camera shop to see if they behave the same way.


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Old Feb 20, 2007, 8:01 AM   #4
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I've heard it 3 or 4 times now. It occurs on exposure times > 1 second and lasts for the duration of the entire exposure (mirror up to mirror down). It occurred last night on a 4 second exposure. I took another shot immediately after and there was no noise. Both shot looked identical.



--FrankD
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Old Feb 20, 2007, 8:29 AM   #5
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I do remember seeing some mention of this kind of thing on long exposures, with the assumption that it was the AS getting confused if memory serves.

If it was on a tripod, you may want to disable it (as the theory is that it can cause some kind of feedback loop that way if there is no movement, although I haven't personally noticed it, most manufacturers do recommend disabling stabilization systems when using a tripod).

If you're concerned about it being abnormal, I'd find a nearby retailer that has this camera on display and see if it exhibits the same symptoms as yours or not. It may even be something as simple as the new "dust buster" feature vibrating the CCD to clean it after a long exposure.


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Old Feb 20, 2007, 8:50 PM   #6
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Hi JimC,

Good point! I leave SSS enabled and forget about it. The camara was on a tripod at the time.

I have taken a number of time exposures but only hear the noise infrequently. I don't think that I can provokeit ina determanistic manner yet so a visit to the local camera store may not prove very much.

I'll have to dig out the manual and refresh my memory with regard to sensor cleaning. I do recall the sensor cleaning is performed on user command via the menus but I don't recall anything about auto cleaning. If it was cleaning the sensor it must have been doing it during the exposure. As I mentioned before, the noise starts at shutter release and lasts until mirror down.

Thanks,

--FrankD
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