Attached is a cropped section of a night shot just done with my new Canon 6D.
Problem: 22 images taken and on every image there are red blotches all over the image and they are all in the exact same position on every frame, no variation and not random like noise. There are also quite a few hot and dead pixels to add to the mess.
Images were all RAW, 4 min exposure and only at 800iso. Both RAW and converted JPGs have the same pattern.
I bought this camera as it is supposed to have a very sensitive chip suitable for astro imaging. Does it look like i have a dud or is this mess par for the course? I have a Canon 500d and never seen anything like it.
Run the in camera sensor cleaning about three to four times consecutively, this should reset the pixel mapping and get rid of stuck pixels. Not sure about the red blotches though.. maybe a defective sensor?
Do you have in camera high iso/long exposure noise reduction on?
Answers to all questions
Q1. No noise reduction function on. Shouldn't need it. These red marks are consistent in one location every exposure, not random like noise. have done the same imaging with a canon 500d (no in camera noise reduction and perfect result).
Q2. Yes have done a test with dark frames as well. Same result.
Q3. Have tested conversion with 3 software programs (a) eos software, image browser that comes with the camera (b) Adobe DNG Converter and (c) Adobe Lightroom latest version
If anyone has a 6D can they just do a test for me.
I shot that image in RAW, 4min exposure iso 800 using 16-35mm EF L Canon lens. Not that the lens would mean anything. RAW or processed all images have the same pattern.
Canon rep just tried to tell me its noise from having the shutter open for 4 minutes. Come on guys.
Interesting response from the camera shop i bought it from (Authorised Canon dealer not Grey import) . Just rang them to say that Canon suggested i send it to them via the retailer so they can have a look at it.
The guy at the store said no worries, if you think there is a problem just send it back with copy of Canon warranty and receipt and we'll just send you a new one, no questions asked. Unless you want to wait 6 weeks for Canon to look at it.
Not bad service, but if anyone has any ideas i'd like to get to the bottom of this i'd hate to think that there is an inherent fault in the sensor.
Wow. That's rather disturbing Carl. Any chance you can get a hold of J. H's to do a test with same settings? I had a play with the RAW. My DPP couldn't read the 6D file because of it being an older version for my cameras to see if it automatically detected and removed the hot pixels (like it does on my files). Opened fine in Adobe Camera Raw. I was able to easily tune out the red blotches/pixels/noise , but as Mike says, the 6D should have bugger all of that sort of thing full stop. If they are prepared to replace with new at no cost, I would say go for it by the looks.
I'm still a bit confused. Are you worried about the individual red pixel that are all over the image or red patches that are bigger than individual pixels ?
Hi Terry
Hot pixels are easily defined and removable. My image is just covered with red and blue dots tat don't look like they have a sharp edge. These dots are in the exact same position on all 20 images, surely it can't be random noise. I have no idea what they are. The guy from Canon suggested that it was acceptable noise, i find that hard to swallow on a camera that has been given a lot of hype about low light sensitivity.
I just did the same exposure test tonight shooting both RAW and JPG. The JPG was not too bad, but he RAW was just as bad as the above sample.
Hi Mike
Did you get a chance to download the image from the link is sent you so you can see the RAW image?
Also when you took the 18min and 53min exposure was it in RAW or JPG. Is there a noticeable difference between your result and my image
Regards
Carl
At this stage it's looking like a new camera for me