Milky way @ the Wilsoms Prom & Noise Reduction comparison

[matt34 (Matt)]

Here is a shot from a recent trip to Wilsons Prom, when the moon was hiding I have a large backlog of files to look at, the main reason I started editing this shot was to check and compare how I'm doing my workflow and check that its providing the best Noise reduction etc. And that will explain the second shot, I used 4 slightly different techniques for Noise reduction, lens correction . Once I settled on what I thought was best I then did some tonal curves adjustments etc in Lightroom

Large of the shot

Cannon 60D, f2.0, 10 seconds ISO3200

Large of comparison

So here are 4 100% crops of this shot with different techinques from left to right they are
- Canon's DPP software
- DPP + the inbuilt Digital Lens Optimiser (DLO) in the DPP software
- All RAW NR & lens correction removed in DPP and done in Lightroom only
- Basic "default" values in DPP then in Lightroom lower NR settings than in no3.

There is a slight colour difference in the 2 shots in lightroom, I left it as the default from loading the image (same with DPP) however they look slightly warmer.

I think it confirms that I had thought (and luckyily what I had been doing) that a mix of both (eg the last shot) seems to handle the noise the best while giving the most detail.

Whats your thoughts are your thoughts? Which processing works best for reducing noise? What other methods are people using?

[ourkind (Carlos)]

Hi Matt,

in my opinion the first of the 4 images looks best, the large single image whilst the noise reduction is effective it seems as though some of the stars on the top right half are suffering chromatic aberration.

I use the "Noise Reduction on long exposures" setting on my camera, then in Photoshop RAW I apply "lens correction" and "luminance" approx 20%. Afterwards if image still appears grainy I will sharpen and guassian blur.

[gregbradley]

Long exposure noise reduction only. If there is any residual noise I use Adobe Lightroom as its noise reduction is fantastically efficient and does not damage the rest of the image much.

Ideally none. All noise reduction seems to damage the fine stars to some degree. Sometimes I use Noise Ninja plug in which is like selective noise reduction in that it only smooths dim noisy areas and leaves bright less noisy areas alone.

Greg.

[Phil Hart]

Love a good test. Nice work.

The first two images have dark halos around the stars which I would be trying to avoid.. the de-fringing has been taken too far with those settings.

I would be really interested to see the Digital Lens Optimisation applied to corners of an image where the star shapes are not 'stars' anymore and see if it can improve those.

Phil

[matt34 (Matt)]

Originally Posted by ourkind

Hi Matt,

in my opinion the first of the 4 images looks best, the large single image whilst the noise reduction is effective it seems as though some of the stars on the top right half are suffering chromatic aberration.

I use the "Noise Reduction on long exposures" setting on my camera, then in Photoshop RAW I apply "lens correction" and "luminance" approx 20%. Afterwards if image still appears grainy I will sharpen and guassian blur.

Carlos thanks for your thought/opinion, I think with the current lens (24mm f1.4 II that CA is tough to deal with in the corners when the lens is wide open even stopped down to f2.0 isn't enough)

Do you know much about how the in camera noise reduction works? I played with it a couple of years ago But should do "new testing" my understanding was that it takes a dark frame and subtracts the noise from the image frame, my questions around that are does it save that to the RAW? Does the camera do it the a jpg version? will the "subtraction" only be done in the cameras only RAW reader (like canon's DPP)
I think I remember it didn't seem to do alot to the shots I was processing but that could have been the RAW viewer. Time for another test

Originally Posted by gregbradley

Long exposure noise reduction only. If there is any residual noise I use Adobe Lightroom as its noise reduction is fantastically efficient and does not damage the rest of the image much.

Ideally none. All noise reduction seems to damage the fine stars to some degree. Sometimes I use Noise Ninja plug in which is like selective noise reduction in that it only smooths dim noisy areas and leaves bright less noisy areas alone.

Greg.

Thanks Greg, do you know how the in camera NR works? I've heard Noise Ninja is good.

Originally Posted by philiphart

Love a good test. Nice work.

The first two images have dark halos around the stars which I would be trying to avoid.. the de-fringing has been taken too far with those settings.

I would be really interested to see the Digital Lens Optimisation applied to corners of an image where the star shapes are not 'stars' anymore and see if it can improve those.

Phil

Hi Phil

I hadn't spotted the halo's until you mentioned it. Ill look out for that in processing in future. I'll have to look at the default DPP settings to see if the haloing exists. I'll also grab the DLO shots of the corners to compare to see if it helps the stars look more like stars. More test data to come, I just have to recover from a PC crash first


I also like the more colour in the stars in the last 2 shots, not sure if thats the Lightroom processing or how the stars looked, but it seems the higher DPP processing removed some of the orange/pinky colour in some of the bigger stars.

[multiweb (Marc)]

As I go I find that noise reduction levels should be different depending how you're going to present your pictures.

If you're going to show a close up close to 1:1 or 80%-90% then you'll need some kind of clever noise reduction algorithm to make your image smooth while keeping deconv details and sharpening.

If you're ultimately going to do a mosaic and end up with a 50% or even 20% display then it's best to not noise reduce as your contrast will be enhanced anyway when you 'bin' so to speak the whole picture and the noise won't be noticeable.

I often found that large mosaic I stitched at 1:1 taking care of noise at that image scale looked lifeless and 'faded' when reduced. So I often ended up doing two versions. One with noise reduction and the other without for smaller display size.

[matt34 (Matt)]

Hi Marc

That's a very valid point, what looks best for the web and small screen would probably be different to a large pic or print perhaps.

I guess I'm looking for what works best for large view/print. I like to print up some of my best shots. I haven't printed alot of nightscapes yet and the ones I have were on canvas so that hides some of the grain/noise sins

[LewisM]

The only plugin I find much good is Imagenomics Noiseware Professional - you can customise ALL the variables to achieve the desired result. Never had an issue with it, yet. I have all of Imagenomic's and Nik's plugins/filters, and swear BY Imagenomic, whilst sometimes swearing AT Nik's

[gregbradley]

Some good tips there. Good point from Marc. A large mosaic does look better with no noise reduction. Exactly as he described.

Noise reduction algorithims are probably getting more and more complex. I think it is now starting at the RAW level with hot pixel cleanup like Nikon did poorly in the late 90's and is much better now.

6D probably has some extensive algorithim going. It would be proprietary to Canon. I am sure it is much more than a simple blur.

Long expoure noise reduction is a dark subtract and it gets rid of amp glow as well if there is any.

Sony recently updated the firmware for Nex cameras and there were a number of complaints that the RAW data was being manipulated. It seems to be a trend amongst camera makers to do this. Probably because noise levels at high ISO is one of the review points that is checked and there can be a lot of internet discussion and comparisons between camera makes on their noise performance.

So apart from more efficient sensors we are seeing more reliance on firmware processing of noise to improve performance.

Greg.

[multiweb (Marc)]

Noiseware professional is an awesome photoshop plugin. I used since day one. John Glossop put me onto it 6yrs ago. I have also noise ninja and neat image but they're not as good as Noiseware. But the best targeted noise reduction I've seen by far and that works when all other fails is Startools. It works in the 16bit environment of the FIT files and is integrated in the workflow (i.e. sharpening, deconv, strectching). It yelds the best results. Haven't seen anything that comes even close to it. (yet).

[matt34 (Matt)]

Hi Guys, some great discussion and points on the threads, I'd never heard of Noisewarebut will look into it.

I'll have to do some more tests with Canon's long exposure NR and check out the results.

Thanks again for all the info shared here