Canon 450D

[Rossco72]

Hi all,

I've been having some issues with my Canon 450D. The image files and dark files appear to have a "glow" down one side. I have added a sample below. This gets significantly worse at higher ISO's and longer exposures.

Anyone know what this is, how to cure it or whether or not they have any similar issues with their Canons?

Cheers

[jgs001]

If I had to guess, I'd say that was Amp glow. But that's odd... I don't get that with my 450d. Even after a 34 minute exposure I have no amp glow. How long have you had the camera ?

[saturn5]

Looks like amp glow to me as well.I read on a camera forum that the 450d and newer models turn off the amp during long exposures.

Also read that if you use an alternate power source instead of a battery like a power tank or the likes the problem is solved.

Cant say i've tried it but i'm sure someone can verify it or tell me i'm talking rubbish.

[Rossco72]

I bought the camera in the middle of June, Since then I have only had a few nights of clear skies to try it out and all of my images with exposures of more than about 2 minutes suffer from this issue. Even with the in camera noise reduction on taking a matching dark for every light the same symptom persists.

[arad85]

Hmm.. I have a 450d. I've done some 20 minute dark exposures at room temp and they don't show this amp glow. There's a lot of options in the settings.. Not sure which would cause this, but have you changed any?

[Rossco72]

I've tried all noise reduction on, all noise reduction off, long exposure NR on, high speed ISO on, it all pretty much comes out the same. at a push I can get 2 minutes at ISO800 but anything more just gives this purple gradient from the left hand edge.

[brianb]

Amp glow isn't too much of a problem, just shoot dark frames (same exposure as the light frames) & subtract them. Unfortunately with a camera which isn't temperature controlled you have to match the darks & lights for temperature as well as exposure length & ISO setting.

[jgs001]

Rossco, I found this Telescope Reviews: 450D - OK this can't be amp glow so what is it?, it might be worth trying to turn the display off whilst shooting. It's not affected me in anyway, but try it and see. Press the display button whilst the display is showing the camera settings.

The only other thing, it might be worth getting in contact with Canon and see what they say. It's still in warranty.

[Rossco72]

OK, solved my own problem! Basically i'm a bit of a daftie!!

The link above is actually my own problem. Kevin from DSLR Astromod was helping me out as I purchased the camera from him.

I was using live view to try and get the focus right and then going straight into 5 minute exposures and was getting the problem that started this thread. However a bit of time spent googling last night i found a test review from a chap in the states who commented that for long exposures it was essential to turn live view off for long exposures to contain and limit the noise.

Once I tried this it all works fine. Tried a 20 minute dark frame last night and there was a fair bit of noise but no bright areas and no gradients so i'm happy.

Thanks for the suggestions and information guys.

Stuart