topic Re: color anomaly in astro photography in EOS DSLR & Mirrorless Cameras

EOS R7 color anomaly in astro photography

mdphotography — Tue, 18 Feb 2025 17:14:15 GMT

my first attempts at astro photography and I noticed a pink spot and streak on almost all my shots, regardless of exposure time (2 - 30 sec), iso (100 - 32000) and aperture (f2.8 - f20). I was able to remove it in post production but was hoping somebody had a technical solution. You can see it just below center to the right in the example below and it appears in every shot but the "blue hour" ones, regardless of where I pointed the camera. I was in a pretty dark camp site, but it's possible there was some stray light from one of the other campers.

body: EOS R7

lens: Sigma 18-50mm F2.8 DC DN | C

iso5000 - f/14 - 18mm - 30 sec

Re: color anomaly in astro photography

kvbarkley — Tue, 18 Feb 2025 17:11:28 GMT

Does it happen when you take a "dark frame" - just do an equivalent exposure with the lens cap on.

Re: color anomaly in astro photography

mdphotography — Wed, 19 Feb 2025 14:46:24 GMT

yep - saw it....I think this means I may have a bad lens 😕

at least it's new and still under factory warranty!

Re: color anomaly in astro photography

justadude — Wed, 19 Feb 2025 15:16:21 GMT

That is more likely to be caused by the image sensor, than the lens.

Re: color anomaly in astro photography

kvbarkley — Wed, 19 Feb 2025 16:13:34 GMT

Yeah, often this is when the camera does not compensate properly for the rows of focusing sensors.

Re: EOS R7 color anomaly in astro photography

mdphotography — Wed, 19 Feb 2025 16:19:45 GMT

is that a physical issue with the camera body or do just need to finesse the settings a little more? this was my first attempt at astrophotography so I expect a bit of a learning curve

Re: EOS R7 color anomaly in astro photography

kvbarkley — Wed, 19 Feb 2025 16:21:02 GMT

Contact Canon and discuss it with them.

Re: EOS R7 color anomaly in astro photography

justadude — Wed, 19 Feb 2025 17:57:23 GMT

I do a lot of astrophotography. I have since the film days in the 80's. I've never seen anything like this from settings being off, or even close to this from the settings... especially with it being a perfectly straight horizontal line. This is very often a sensor issue.

Re: EOS R7 color anomaly in astro photography

mdphotography — Wed, 19 Feb 2025 20:19:05 GMT

thanks for the advice!

Re: color anomaly in astro photography

jrhoffman75 — Wed, 19 Feb 2025 22:30:29 GMT

@mdphotography wrote:

yep - saw it....I think this means I may have a bad lens 😕

at least it's new and still under factory warranty!

When you take a proper dark frame with the lens cap on no light comes through the lens.