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DPChallenge Forums >> Hardware and Software >> I think Canon killed my sensor - advise please
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04/17/2007 12:01:59 AM · #1
Okay, so I took my 350D into the Canon shop to have the sensor cleaned. I've had them do it once before. It came back and my initial test shots indicated that the sensor-dust was removed. Next time I used my camera I found my images had an unusually high amount of noise. This is especially the case with the darker areas of the image, in lower light condidtions Now I'm not talking about long exposures in the dark. With subsequent shooting I have found it occurs even in cloudy condidtions or during the 'golden hour' time. This happens even with ISO 100. Also, as far as I can tell the exposure metering in bright light conditions is worse. The timing couldn't have been worse as it happened just before my brothers wedding. I have reviewed all camera settings (including parameters that I wouldn't usually touch myself), and all is as it should be.

So; what are my options? Does anyone have any previous experience with problems like this? Can I demand a new sensor? What about the personal cost to not have decent shots from my brothers wedding.
04/17/2007 12:09:46 AM · #2
Originally posted by PaulE:

Okay, so I took my 350D into the Canon shop to have the sensor cleaned. I've had them do it once before. It came back and my initial test shots indicated that the sensor-dust was removed. Next time I used my camera I found my images had an unusually high amount of noise. This is especially the case with the darker areas of the image, in lower light condidtions Now I'm not talking about long exposures in the dark. With subsequent shooting I have found it occurs even in cloudy condidtions or during the 'golden hour' time. This happens even with ISO 100. Also, as far as I can tell the exposure metering in bright light conditions is worse. The timing couldn't have been worse as it happened just before my brothers wedding. I have reviewed all camera settings (including parameters that I wouldn't usually touch myself), and all is as it should be.

So; what are my options? Does anyone have any previous experience with problems like this? Can I demand a new sensor? What about the personal cost to not have decent shots from my brothers wedding.


I once had to send my older digital Fuji in for repairs and when I got it back it had another problem and it was even worse than the original problem. I rang them and they said send it back and they had to "recalibrate" to factory standards. I think they plug ged it up to a computer with a programme in it that didi the work. That fixed the problem and I didn't have to pay for it.
04/17/2007 12:13:27 AM · #3
I think that I doubt canon did any damage to the sensor that would result in increased noise. If they damaged something while cleaning it, it would be the protective filter in front of the sensor and not actually the sensor itself. You would see dark streaks or spots on the photo if it were scratched. Do you shoot in Jpeg or Raw? Did any of the parameter settings get bumped up like shapness, which might affect image quality? I would check all those or reset to defaults and see if that changes anything. If it doesn't I would take it back to Canon and have them look at it. Good luck and hope this helps. P.s. Could you post a picture for us to see?

Message edited by author 2007-04-17 00:14:36.
04/17/2007 12:19:37 AM · #4
Originally posted by trevytrev:

I think that I doubt canon did any damage to the sensor that would result in increased noise. If they damaged something while cleaning it, it would be the protective filter in front of the sensor and not actually the sensor itself. You would see dark streaks or spots on the photo if it were scratched. Do you shoot in Jpeg or Raw? Did any of the parameter settings get bumped up like shapness, which might affect image quality? I would check all those or reset to defaults and see if that changes anything. If it doesn't I would take it back to Canon and have them look at it. Good luck and hope this helps. P.s. Could you post a picture for us to see?


I shoot in RAW, and I have verified all the settings and parameters. I don't see any scratchs or markings - just really, really bad noise where the image is dark. I agree that I wouldn't expect Canon to do anything to do anything that would impact noise or exposure metering, but this is the only conclusion I can make.

I will post an image when I get home this evening.
04/17/2007 06:58:55 AM · #5
post a RAW file?
04/17/2007 10:44:13 AM · #6
I can't post RAW, but here are some completely unadjusted shots converted to jpg.

Both the following were taken in good quality light at ISO 100 and exposure compensation at 0. There really should be no noise on the dark material, but there is. These examples are in optimal conditions.



The following display even more noise - taken in slightly less optimal conditions. Nonetheless the noise shown here also exceeds my expectations:
Exposure compensation -2/3
Taken at 17:54

What do you think?
04/17/2007 11:07:14 AM · #7
Grab some 100% crops of those shots so we can really see what the noise looks like. The pictures looks fine to me.

Your supposition that there should be no noise in the darks is probably a bit too optimistic. Noise in darks is the bane of digital photography and the 350 probably isn't the best body at removing it.

Message edited by author 2007-04-17 11:09:54.
04/17/2007 11:17:54 AM · #8
Your test shots look fine. Relax and step away from you camera for awhile!

04/17/2007 11:17:55 AM · #9
I think you're paranoid dude LOL. I agree with Achoo. They look fine to me.

C'mon you're just fishin' for a reason to get a new body huh? LOL What do ya want, a 5D, one of those new Mark III's.

Message edited by author 2007-04-17 11:20:40.
04/17/2007 11:19:28 AM · #10
Originally posted by PaulE:



What do you think?


I think you should see an ophtalmologist or optician, the pictures look almost noise-free.
04/17/2007 11:19:51 AM · #11
I can't see anything that jumps out either...

The shadow of the fella in the first picture looks a bit funny, but more like compression artifacts?

Can you see this "noise" on prints or just your monitor? have you tried other monitors?

Message edited by author 2007-04-17 11:20:35.
04/17/2007 11:20:54 AM · #12
Jason - I agree with your points; but I've shot 10000 images with the camera and do have a very good feel for the quality and the noise. I am talking about some pretty severe noise in extremely ideal conditions. I will post a 100% crop.

I like the quote in your signature. Nelson Mandela used it in his inaugural address (without reference), so I have always attributed it to him.
04/17/2007 11:30:30 AM · #13
Here are some 100% crops from the images originally posted:




Message edited by author 2007-04-17 11:36:16.
04/17/2007 11:31:25 AM · #14
Originally posted by NstiG8tr:

I think you're paranoid dude LOL. I agree with Achoo. They look fine to me.

C'mon you're just fishin' for a reason to get a new body huh? LOL What do ya want, a 5D, one of those new Mark III's.


Yeah, I want a new body; but it won't happen soon so I need to solve this problem.
04/17/2007 11:40:59 AM · #15
Sorry, but these pics look fine to me, I don't see the noise you mention. Even at 100% crop they look fine to me.
04/17/2007 11:43:40 AM · #16
I just had my D200 sent into Nikon UK for some work it had to go back again because all they did was clean the sensor they said.. anyway.. after coming back for a second time fixed and with a sensor clean.. i thought ide put it to the test..

the sensor was totally covered in crap but after a dry wipe (i did it myself) it was very nice, so they did do something, maybe...

Also I too noticed really high noise levels *insert bitchy canon Vs Nikon comment here*
it took me a day to realise what the hell it was, lucky for me they had set the thing to Auto ISO and reset the menu so no noise reduction etc etc so the shots I took were at ISO800 and of cause a bit noisier than the usual ISO100.

I think if you take it back to Canon and complain that the images have been ruined due to a recent sensor cleaning by them they will HAVE to look into it.. especially if you take before and after crops to them (include exif for date and settings etc)

Looking at the crops they seem to be OK but I would not be happy about any change in my camera..

Take it back, complain, and show them proof.. you win the match.
04/17/2007 11:50:48 AM · #17
There's no unusual noise in those photos. What lens...it just looks like you're using a sub-par lens in the 100% crops to be completely honest.
04/17/2007 11:56:04 AM · #18
Originally posted by deapee:

There's no unusual noise in those photos. What lens...it just looks like you're using a sub-par lens in the 100% crops to be completely honest.

DP; I was using my 24-105mm f/4.0 L IS USM lens. Not that.
04/17/2007 11:56:12 AM · #19
I don't see the noise you are talking about.
04/17/2007 11:57:11 AM · #20
Guys, could you try downloading the crops and looking at them in PS. Please. I'm starting to think I'm going mad.
04/17/2007 12:16:28 PM · #21
I see some mild noise, but I think it's easily within the acceptable range. Most of what I see (I think) is texture on the clothes.

Even a mild run with NI should easily take care of that. Also "expose for the highlights and process for the shadows".
04/17/2007 12:34:40 PM · #22
Originally posted by DrAchoo:

.... Also "expose for the highlights and process for the shadows".


It's rather the opposite, it's best to expose "to the right" as far as possible, using the histogram and process for the highlights. Good explanation Here.
04/17/2007 12:39:18 PM · #23
Originally posted by doctornick:

Originally posted by DrAchoo:

.... Also "expose for the highlights and process for the shadows".


It's rather the opposite, it's best to expose "to the right" as far as possible, using the histogram and process for the highlights. Good explanation Here.


We're saying the same thing. I was just phrasing it as a play on the film version which is "expose for the shadows, develop for the highlights".

I agree, basically you push the histogram as far to the right as you can.
04/17/2007 08:15:39 PM · #24
Originally posted by PaulE:

Originally posted by deapee:

There's no unusual noise in those photos. What lens...it just looks like you're using a sub-par lens in the 100% crops to be completely honest.

DP; I was using my 24-105mm f/4.0 L IS USM lens. Not that.


Yes, exactly...a sub-par lens. Did the lens say Nikkor on it? haha just kidding man.

Who knows...I know I get more noise than that when I shoot at the lowest ISO setting I have...especially if I didn't expose properly.
04/17/2007 08:44:01 PM · #25
Hi Paul. I have that same camera and I can assure you that the noise you're seeing is not excessive for those shots. I would expect my noise levels to come out eactly the same under those lighting conditions.

If you can show conclusively that previous photos had less noise with comparable lighting and processing, then you should send the camera back with those photos enclosed. But I'd be very surprised if this were the case. Good luck!
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