06-22-2021 09:58 PM - edited 06-23-2021 07:45 AM
So I bought a 90D a few weeks ago to replace my aging T4i for some astrophotography. The first couple nights out I was having a few issues I'm still working out, but one of the big issues was the impressive amount of what appear to be bad/hot pixels in my images. When I say impressive, I mean impressive, its like I created my own artificial star field impressive.
I was using 5 minute subs (individual photos) and ISO 1600 (though on my previous ISO 800 shots they were still just as bad), and the level of bad/pixels was concerning. You can tell that they are bad/stuck pixels because as the intended star field shifts between the photos, these pixels remain in place.
This is one of my dark frames, aka an image taken at roughly the same temps and ISO as the "light" frames, but with the lens caps on and no external light reaching the sensor. This is a small patch at 100% pixel for pixel (this is NOT the whole frame, but a small 1000x600 100% zoomed in cropped patch), and it is like this across the whole frame, on every image. Is this high of a saturation of bad/hot pixels on a brand new camera normal?
I know my T4i was nowhere near a fraction of this, which is why I was so suprised by it. Though my 6D2 does have a fair amount of bad/hot pixels I have to contend with even with 30 second Milky Way images, but again, nothing on this scale/level.
06-24-2021 03:11 AM - edited 06-24-2021 03:13 AM
@hikingphotog wrote:
I got it from Amazon. That is what I'm thinking about returning it, but hence the post here, trying to determine if it is normal for the 90D to have this many bad pixels. Unfortunately the answers haven't been terribly helpful.
Can anyone out there actually confirm if this quite excessive amount of not functioning correctly pixels is expected from a brand new 90D?
Amazon? That could be a good or a bad thing. In any case, were you able to register the camera for a factory warranty? If so, send the camera in to get it checked out.
I am not surprised to see a lot of noise at ISO 6400, including all of the colored pixels.
06-24-2021 09:02 AM
Yeah, I was able to register it fine, no issues. I managed to find a contact for Canon support and asked them if that was an excessive amount of bad pixels but instead of answering if it was normal they suggested I register it and see about sending it in. Which you would think they could see if it was already registered and/or be able to tell me based on the examples I sent them if it was normal or not. But canned responses for the win...
I'm curious where you read that I was getting a lot of noise at 6400? The images I posted were at ISO 1600, for 1 minute or 5 minutes.
06-25-2021 02:24 AM - edited 06-25-2021 02:38 AM
You will get a lot of hot pixels in a 5 min exposure, especially if it's warm outside. It's perfectly normal and your camera is not broken. For astrophotography you would either need a camera with a cooled sensor (3rd party mod), or just take multiple high-ISO exposures and combine them in post. Sensor modifications also could be useful to capture wavelengths outside of the visible light spectrum.
Edit: here's a 12 min exposure for ya (R5): https://drive.google.com/file/d/1mnfPPlWsr3mMW5JEvx1qkU9LxInV43wi/view?usp=sharing - hot pixels everywhere!
and the final image https://photostream.us/#/photo/4865 (Topaz Denoise + some manual labor to the rescue 🙂
06-25-2021 11:50 AM
"If you just recently bought your camera, then it should still be under warranty."
"I ... contact for Canon support and asked them if that was an excessive amount of bad pixels ... I register it and see about sending it in."
The tech on the phone doesn't know whether it was registered or not. You do need to send it in for a C&C. Even if it is 'normal' at least you will know if it is normal for a 90D. Now you are just wondering and you will always wonder. None of these posts tell you or help you know but a C&C done by Canon will.
06-25-2021 02:25 PM
@hikingphotog wrote:Yeah, I was able to register it fine, no issues. I managed to find a contact for Canon support and asked them if that was an excessive amount of bad pixels but instead of answering if it was normal they suggested I register it and see about sending it in. Which you would think they could see if it was already registered and/or be able to tell me based on the examples I sent them if it was normal or not. But canned responses for the win...
I'm curious where you read that I was getting a lot of noise at 6400? The images I posted were at ISO 1600, for 1 minute or 5 minutes.
I must have gotten you mixed up with Peter's posts. Send your camera in to get it checked out. Be sure to fully describe the problem, and how to reproduce it.
In any case, a 1-5 minute exposure is a lot of time for noise to collect. Think of the noise as rain drips during a very light drizzle of rainfall. A short exposure to the drizzle, and you get a few drops scattered about. However, a much longer exposure could almost mean a full blanket of coverage.
06-26-2021 12:10 PM
"I must have gotten you mixed up with Peter's posts. Send your camera in to get it checked out."
At any rate the posts do nothing to tell whether this 90D is faulty or if it is normal. It has to go in to Canon to be sure otherwise you will always wonder. When you find out then you can do whatever is necessary to get good photos.
06-23-2021 10:02 PM - edited 06-23-2021 10:06 PM
Time for your raw files now...
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