stevei wrote:
My advice, for what it's worth, is that anyone who has this problem should assume, until it's proven otherwise, that the fault only affects a small number of individual 20D copies, and hence they should ask for a replacement for their defective camera. If you find the same problem on the second and third cameras you try, a rethink will be needed.
Steve, my advice to you is that before recommending someone enter the often grueling Canon Warranty Loop of Hell you take the extra 5 minutes to see if perhaps your camera is exhibiting the same problem. I did, and, well... it does.
And yes, I realize I need to clean my sensor.
Edited by Sam Bennett on Nov 17, 2004 at 11:09 AM GMT
I agree, Canon warranty is a nightmare, at least it is in the UK. I'd be asking my retailer for a replacement camera, they're not in particularly short supply any more.
I don't have a 20D, though I'm intrigued enough that I'll try it with my 300D this evening. I was assuming that if it were a common problem, then a lot of other people would have seen it too. On further reflection, though, I suppose there won't be that many people using the internal flash on long exposures, so it might be a common problem that the vast majority of people never experience.
I was also working on the basis that getting a replacement camera from the retailer is very little hassle, but I suppose if you've bought it over the internet then swapping it might not be so easy.
Is it possible that this is sensor noise which would be "smoothed" away by JPEG compression, or by Colour/Luminance smoothing?
I've seen this in some shots with my 10D (EDIT: at ISO200) , lit via my (bounced) 420EX, but assumed it was sensor noise in lower-lit areas of the image.
Interested to see the answers from Canon though, as my 10D is still in the warranty period
Steve
Edited by Steve Knowles on Nov 17, 2004 at 04:18 PM GMT
stevei wrote:
I don't have a 20D, though I'm intrigued enough that I'll try it with my 300D this evening. I was assuming that if it were a common problem, then a lot of other people would have seen it too. On further reflection, though, I suppose there won't be that many people using the internal flash on long exposures, so it might be a common problem that the vast majority of people never experience.
Yeah, this is my hunch - this is a very uncommon use, I suspect. But I think it will prove to be a good example of a general 20D issue. You see the same sort of banding in other situations, but it isn't as noticeable. Hopefully having something that is so reproducable will help Canon nail the problem for future cameras.
stevei wrote:
I was also working on the basis that getting a replacement camera from the retailer is very little hassle, but I suppose if you've bought it over the internet then swapping it might not be so easy.
Yeah, that makes more sense. Unfortunately, I've found that even with smaller local retailers the arrangement with Canon is not such that they can simply swap out cameras with any confidence that Canon will credit them with a new camera. I know that if I went back to my dealer they would send the camera to Canon and I would be stuck with shooting with my Rebel for a couple weeks again. Until someone is able to prove this is not a general 20D problem, I'll be hanging on to mine.
Hopefully I'm wrong and the only reason I'm seeing it is because my 20D suffers the same electrical "fault" that jdee's does - but I'm skeptical, as always.
Steve Knowles wrote:
Are you shooting in RAW or not?
Is it possible that this is sensor noise which would be "smoothed" away by JPEG compression, or by Colour/Luminance smoothing?
jdee's images were out-of-cam JPEGs, mine are DPP-processed RAW files. This banding is so well-defined that noise-reduction does not reduce it by any acceptable agree. Others will disagree with that assessment - but for the way I think to noise-reduce photos, there's really no workaround.
Also, again - this issue is NOT limited to high-ISO work. jdee's samples were shot at ISO 200, mine were shot at ISO 100.
I'm not an electrical expert but my question would be is there a chance its picking up RF Interference and the 20D is less well shielded?
Was there any radio transmitting equipment, cell phone etc near to the camera when taking the shot. Sam's shot shows computers were they on when the shot was taken? - I know my small TV has horizontal bands and is unusable on some channels when my computer is on.
Will try some test shots with 20D and report back.
JVasek wrote:
I'm not an electrical expert but my question would be is there a chance its picking up RF Interference and the 20D is less well shielded?
Jan, I highly doubt this has anything to do with it. In this case you can isolate the issue down to the Flash by using it or not. In the problem I see, shots will be different shot-to-shot with identical settings - the key factor being whether the lens is hunting or not at the time the shot is take with AI Servo. In my case, I can make the problem appear or disappear by switching between AI Servo and One Shot mode.
Needless to say, if the 20D had problems with RF interference, you'd see a lot more people up in arms.
Sam as you said RFI unlikely - I've tried some 30 second shots held my phone (yes it was on) next to the camera no obvious difference.
I've tried ISO 3200 and 1600, long exposure with flash and without etc AI servo and lens hunting, and fortunately cannot get any banding as strong as you guys have shown, only feint banding at 3200 that cleaned up with noise reduction software.
I may try some more tests later with different lenses as well, sorry I have not been able to help.
I did call Canon and even sent them a link to a file and they said that they couldn't get the image. I would call them or email them (I think that is what I did) and have them look at the image full-size out of the camera and see what they say. I am going to do the same again and see what they reply with this time.
I've tried with a couple of lenses and I used the settings as noted in Sam Bennett's other thread. link to thread
I can confirm that I can create the same/similar banding at 100 ISO on my 20D using the internal flash, the banding in my case remains when I use AI-Servo or One shot and is most visible in darker areas of the shot. The shot was clean when I did not use the flash.
I've tried the same settings with a 550EX no banding. I also repeated this with the 10D just in case again no banding.
Are you taking RAW images? This could be a problem with the software being used to convert to JPEG. Those "bands" look like some sort of conversion error, I know I have gotten errors using the DPP software that came with my 20D, which caused bad artifacts in RAW conversion.
hqmhqm wrote:
Are you taking RAW images? This could be a problem with the software being used to convert to JPEG. Those "bands" look like some sort of conversion error, I know I have gotten errors using the DPP software that came with my 20D, which caused bad artifacts in RAW conversion.
It occurs with in-camera JPEGs and across all RAW-to-JPEG conversion software.
I have called canon a couple times today. The first guy said that he has had a few people with this problem and canon was able to fix it, and thesecond guy said that no one has heard of this problem. Im starting to lean tward getting my money back on the 20D and then keep using my 10D until I hear that canon has fixed the issue. (By the way, my 10D does not have the same problem...)
Here is an example of my banding. This was with NO flash, 100 2.8 at ISO 1600. Converted to BW so the banding really showed up when I did that. Sorry it is so big but it was the only way I thought you could really see the banding.
Craig, can you share more exif info on the picture ? Sam got banding @1600 ISO when using the 50/1.4 lens in combination with AI Servo. What was your lens / settings ?
File: _MG_1025.JPG
File size: 2,998KB
Camera Model: Canon EOS 20D
Camera serial number: 0320111961
Firmware: Firmware 1.0.5
Owner: unknown
Date/Time: 2004:10:29 04:34:05
Shutter speed: 1/60 sec
Aperture: 2.8
Exposure mode: Av
Flash: Off
Metering mode: Evaluative
Drive mode: Continuous: frame 1
ISO: 1600
Lens: 100mm
Focal length: 100mm
AF mode: One-shot AF
Image size: 3504 x 2336
Rotation: none
Image quality: Fine
White balance: Auto
Saturation: Low
Sharpness: Normal
Contrast: Low
Picture Effect: Normal
Tone: Normal
Custom Functions:
CFn 1: SET button function when shooting: Change parameters
CFn 2: Long exposure noise reduction: On
CFn 4: Shutter release: AF; AE button: AF lock, no AE lock
CFn 5: AF-assist beam/Flash firing: Only ext. flash emits/Fires
CFn 8: ISO expansion: On
CFn 9: Bracket sequence: 0, -, +, Auto cancel: Disable
CFn 11: Menu button return position: Top
CFn 13: AF point selection: Multi-controller direct
CFn 16: Safety shift in AV or Tv: Enable
CFn 18: Add original decision data: on
Interesting Craig, thanks. This isn't totally surprising. I think that AI Servo just increases the chance of seeing the problem greatly - even when using AI Servo on the same kind of shot, you'll only see it about 50-75% of the time. I think this is becaue the lens motor has to be engaged at a particular moment when you release the shutter. I could see quick One Shot shooting resulting in it as well if there's no lag between focusing and then taking the photo - but since most of us focus, pause to frame, then take the photo, I think it's just less evident.
And if SCOR hasn't noticed already - No, the AI Servo problem is not limited to long exposures or ISO. I've seen it on normal shutterspeeds down to ISO 400.
Craig, thanks. Given the subject you shot I had not expected AI Servo to be used.
Well is does leave us with a problem....
The banding is there and the predictability of it occurring varies apparently from close to 100% in the setup Sam advised us to test with, to 50% in the 50/1.4 plus AI Servo setup, to incidental banding as seen in Craig's sample. Now we can continue to try and get as much banding photo's with full exif, post processing story, shooting conditions, battery status etc, but that would be a long way to go. This was tried with the 1.04 firmware upgrade lockup situation where we all posted what type of CF card was in our camera to perform the upgrade. In the end it turned out to be something completely different (specific lens on camera during uppgrade).
Sounds like a having conversation with Canon experts on the subject would be the logical next step. Honestly, I can hardly believe they are unaware of the problem.
Anyone here that has contacts with Canon beyond normal customer techsupport and willing to discuss it with them ?
Any Canon person on the forum that can let us know if this is being worked ?
