Trying a new technique - weird effects

[g.forwood]

Hi all,

I recently had this shot rejected for Over Processed / Bad postprocessing and JPG compression artefacts. I use a 7D, and if anyone is familiar with the camera, it generates a lot of noise in the blue spectrum, even at ISO 100. So I thought, why not try some selective noise reduction. So I selected only the sky, copied it to a new layer and did a full strength Noise Ninja filter. It seemed to work perfectly (as far as I could tell) but obviously something isn't right as the screener's comment was "weird effects in the sky".

I'm just wondering if someone could enlighten me as to what the weird effect is and some advice as to what else I can do to reduce the excessive noise in the sky (is a little noise ok?)

Many thanks,

Gareth

[LX-A343]

Noise reduction combined with JPG causes such bandings. With such light I really doubt you need any noise reduction at all.

[g.forwood]

Thanks for that Gerardo. Unfortunately some level of noise reduction is required (it's really quite bad in the blue spectrum) so I'll remove the affected shots already in queue and post some re-edits in the forums to see if they're acceptable before uploading.

Cheers,

Gareth

[brianw999]

To help you and others this is what it looks like using the screening equaliser tool. Look again at the unequalised image and you can see the semi-circular banding.