A77 Problem ? Can any one explain what is causing this ?

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Ossie
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A77 Problem ? Can any one explain what is causing this ?

Unread postby Ossie » Thu Apr 24, 2014 5:04 pm

I recently had the sensor on my A77 cleaned. One of the first images I took was this one

DSC07879_Bulmer.jpg
DSC07879_Bulmer.jpg (237.36 KiB) Viewed 2465 times

(A77+16-80mm ZA)

After editing I spotted this pattern appearing in the sky.

DSC07879_Bulmer_100-pc-Crop.jpg
DSC07879_Bulmer_100-pc-Crop.jpg (248.44 KiB) Viewed 2465 times


Never having seen it before I thought that it had something to do with the cleaning process but on taking it back to the shop nothing could be seen.

The image was taken at F22 and on checking other images taken before cleaning the pattern was also visible. Does anyone have any ideas as to what is causing this? Is this something that I need to send the camera to Sony for repair?

Any help will be very much appreciated

Ossie

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mvanrheenen
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Re: A77 Problem ? Can any one explain what is causing this ?

Unread postby mvanrheenen » Thu Apr 24, 2014 5:29 pm

Am I correct at seeing a vertical pattern over the full width of the sky?

It looks to me like these are swab stripes: leftover cleaning fluids on the sensor. The pattern could suggest some kind of pattern in the brush used to clean the sensor.

Mark

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Birma
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Re: A77 Problem ? Can any one explain what is causing this ?

Unread postby Birma » Thu Apr 24, 2014 6:29 pm

Eek. My first thought was the same as Mark. Not an expert in this area though so I'm not sure.
Nex 5, Nex 6 (IR), A7M2, A99 and a bunch of lenses.

Ossie
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Re: A77 Problem ? Can any one explain what is causing this ?

Unread postby Ossie » Fri Apr 25, 2014 4:40 pm

mvanrheenen and Birma

Thanks for your feedback

mvanrheenen wrote:Am I correct at seeing a vertical pattern over the full width of the sky?


Yes that is the problem. I too thought at first it was some sort of residue from the cleaning process but having checked it appears in other images shot at F22 and taken before the sensor was cleaned. I can't see it in any other images.

Ossie

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mvanrheenen
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Re: A77 Problem ? Can any one explain what is causing this ?

Unread postby mvanrheenen » Fri Apr 25, 2014 4:56 pm

Hm, just thinking out loud here, but could it have something to do with distortion due to the small aperture used? Or some kind of diffraction effect?

Could you test with another lens?

Ossie
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Re: A77 Problem ? Can any one explain what is causing this ?

Unread postby Ossie » Tue Apr 29, 2014 2:01 pm

Visited the camera repairers this morning. Their initial thoughts are that it could be a problem with the in camera image processor or early signs of the sensor failing. They are investigating further and I now await their report.

In the mean time it's back to the A700.

Ossie

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Birma
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Re: A77 Problem ? Can any one explain what is causing this ?

Unread postby Birma » Tue Apr 29, 2014 3:56 pm

Ouch. Fingers crossed that it is a cheap and quick repair.
Nex 5, Nex 6 (IR), A7M2, A99 and a bunch of lenses.

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Re: A77 Problem ? Can any one explain what is causing this ?

Unread postby David Kilpatrick » Fri Jun 20, 2014 12:55 am

Sorry, I missed this. That's a typical wet cleaning mark. It is caused by the swab dragging over the sensor and leaving a residue. The solution is wet cleaning by someone who knows how to wet clean. Ideally Sony sensors should not be wet cleaned and should never be cleaned by any operator unaware of the SSS carriage mechanism and the need for extremely gently pressure as the sensor, unlike Canon and Nikon, is mounted on a flexible sprung carriage.

Ossie
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Re: A77 Problem ? Can any one explain what is causing this ?

Unread postby Ossie » Tue Jul 08, 2014 11:50 pm

My A77 has been repaired. Sony replaced the Shutter Unit, Mirror Box and what they described as the “Protective Cover” No charge was listed for these parts. The only charge was for labour plus tax.

Other items listed included “Exposure Meter, Speeds Checked, adjusted and repaired as necessary, Auto Focus Mechanism Checked and Tested, Computer test carried out and checked to standard”

No feedback on what caused the original problem was given. As there has been no specific mention of the sensor being replaced I assume the problem must have been elsewhere.

I had hoped to have the camera available for a recent trip to the USA but as the start of the trip came closer and there seemed no chance of it being repaired in time I had to buy a S/H A77 body.

Ossie


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