Long Exposure = Noise

I'm just back from a terrific trip to photograph the Aurora. My story and a link to the photos are here

I used a Canon 5DIII and 16-35II. From what I've read, I was expecting very little noise at high iso. Not true.

The jpg I posted here is two versions of a small section of
this image. The version on the left has ACR processing (moving the sliders on the first panel plus lens correction) with no noise reduction applied. The version on the right has the same ACR processing with ACR noise reduction applied using values of 50 50 0 50 50.

I tried various combinations of noise reduction settings, but it didn't change the predictable outcome. The more you reduce noise, the more you lose detail.

I hope you can see how much noise is present in the version on the left. If you have the patience, you may have to download the image and zoom in.

By the way, the ACR processing, other than noise reduction, didn't affect the noise at all.

The settings for this shot are F2.8 20 seconds, iso 1600. All my other shots with similar settings, from 10-30 seconds and iso 800-3200, had the same amount of noise.

When I set Long Exposure Noise Reduction to Auto, it never kicked in. When I set LENR to On and it did kick in, the amount of noise was exactly the same as when it didn't kick in.

I have shot at high iso for short exposures in raw with similar noisy results. In jpg mode, however, very little noise appears. This is also true with my 7D in jpg mode.

I'm wondering if any of you have had similar experiences. Thanks.

Sounds like a great trip!
The link you gace in the first line does not work, though -

Sandy

I just fixed the link. Thanks, Sandy.

"The version on the left has ACR processing (moving the sliders on the first panel plus lens correction) with no noise reduction applied. The version on the right has the same ACR processing with ACR noise reduction applied using values of 50 50 0 50 50."

Your LENR does not reduce noise, but instead creates a 'dark frame' that is used in camera to subtract hot pixels from the preceding image file.

Thanks, John. The jpg with the two versions can be seen by clicking the View Larger Photo link.

Thanks, Lance.
Although the noise reduction feature is ACR is quite good, it still is not as good as some third party noise reduction software.
A couple of friends of mine who are involved in capturing high-ISO 'starscapes' swear by the Topaz DeNoise plug-in for cleaning up noise while leaving detail intact. You can try a free 30 day fully functional trial version at that link. That may be enough time for you to fix the problems you're having.
Another advantage of using a noise reduction PS plug-in is that it creates a new layer where you can apply a mask and then use the noise reduction selectively where you need it instead of globally as ACR does. Although somewhat tedious, that's a near perfect way to keep detail intact.

Noise reduction is the next to the last step when I process Night sky photos. I utilized the work flow from my friend Roman Kurywczak
.

As a separate layer…..I select the sky out with the stars. In a Hue/Saturation layer…..In the magenta and green channel, I desaturated 100% There is no green or magenta in the sky and canon color noise tends to go to magenta. I also tweak the yellow channel but not as much. You can consider the red channel as well…..but be careful as the stars can be red.

I then use another layer in selective color……..where I remove black in the white channel (not too much because you can blow the whites out) and then add black to both the neutral and black channel to suit your taste. This should get the sky pretty close to where you like it and eliminate most noise. *remember* if the outside edges have a vignette….you can remove it is PS first in lens correction…..this evens out the sky.

For al long time I used Noise Ninja to remove noise……I now like DXO for that reason but even noise reduction is PS works reasonably well. After that…..basic corrections complete the image. Canon tends to push the reds and magenta’s…….so just keep that in mind when doing corrections.

Hope this helps

This is excellent information, Myer. Thank you very much, indeed.

And thank you, Roman.

I enjoyed your images Lance. Looks like a great adventure. Pretty extreme for a South Florida guy.

I use Nik Define for my noise reduction. It works pretty well and the u-points allow me to control how much noise reduction is applied to different areas, which allows me to control how much sharpness is affected. If the noise isn't too extreme I'll use the noise reduction in Lightroom, which works fine for many images.

What an interesting technique you've described here, Myer. Thank you!
I'd love to hear your thoughts on how well this technique worked for you later in this thread, Lance.

Lance----Good to see yiu here...... I too use define(Nik)... you can dowload a free trial on their website---let me know how you make out.
JG
PS- you still have open initation to Portland----I am in Iceland today doing a workshop!
JG