Turn that noise down!

[johnfosteruk]

I've been looking at the most effective ways to reduce noise in my DSLR wide field images and I thought I'd just show what can be achieved in Photoshop. It really makes a difference to the end result and although it won't come as news to a lot of you, inexperienced members may take something from it. The most effective method for me is using blend modes and layers.

This is M45 from the 9th Nov before and after tinkering with the method.

I created 2 duplicate layers (so now I have 3), cloned out the target/brightest stars in the middle layer and gaussian blurred 250%. Then I set the blend mode of the top layer to lighten. 

In the middle blurred layer, sliding the midpoint away from or towards the histogram makes the NR either more aggressive or gives you back some detail if it's too aggressive.

I think this comparison really shows the benefit of taking time over processing, I don't even know how I had the nerve to call the original version finished now

viewed at full size you really see the difference, but it is 30mb.

[mikeskor]

Wonderful images. Good work.