Image problem?

[Starflyer]

Since I first got my Canon 400D I've noticed that it shows far more noise in the red channel than the others, is this normal or am I doing something wrong? To show how bad it is here's the colour channels from an image that I took on Friday night, stacked and quickly stretched;

(click to enlarge)

(click to enlarge)

(click to enlarge)

The green and blue channels are lovely and smooth - please help!!!

Cheers,

Ian

[Psychobilly]

Are you doing bias frames and subtracting them?

Will clean it up a lot...

[Starflyer]

Are you doing bias frames and subtracting them?

Will clean it up a lot...

No bias frames, it was the first time I'd taken flats though (thanks again George)

What are bias frames, how do I take them, and should I have taken them with the imaging train assembled? It's all packed away now but the temperature outside must be similar to Friday evening, so I could grab some at the same temperature.

Ian

[Psychobilly]

Cover the lens , cover the viewfinder and shoot framesa at the same ISO setting that the light frames were taken and at the fastest possible shutter speed ... take alot of them ... they dont take long...and add them into the processing mix...

Billy...

[Starflyer]

Should I brave the cold and take them outside?

[Psychobilly]

Hmmmm.... I'd try them with out going outsidea and it would take ages for the camera to cool down anyway...

[Beyond_Vision]

The red channel is the noisiest on my 400D too

Regards

Kevin

[Starflyer]

Kevin - thanks for the confirmation that it isn't just me

Billy - thanks for the help with the bias frames

I took a load of bias frames and have been messing around ever since. After lots of experimenting with DSS I found that the best result came from creating both a median and average stack and then averaging both of those together.

It was still noisy and I had to fiddle and blur it a bit to get it looking half decent, here's the final image.

Cheers,

Ian

[beamish]

Hya Ian, been reading about your probs and just took a look at your post. I've also just compared it to Blinky's (http://stargazerslounge.com/index.php/topic,35284.0.html ) and can't figure out why with an almost identical set up, apart from the camera (350 as opposed to the 400- both unmodded). I know that it might have alot to do with processing and perhaps the noise issue but your does appear a little "soft" in comparison . Hope you sort it out mate !!

Karlo