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Archive 2013 · Hi iso NR technique for night sky’s.
  
 
ben egbert
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p.1 #1 · Hi iso NR technique for night sky’s.


I am looking for strategies to deal with noise under the following conditions.
Moderate ISO, 800 to 3200. Longish exposures, between 10 and 30 seconds. ˝ to full moon for illumination with detailed landscape foregrounds.

I am familiar with astro techniques for stacking multiple images and using dark frame subtraction etc. This is different than what I am trying to achieve and is aimed at cleaning up a dark sky with little terrestrial detail.
I want clean sky and detailed foreground. It is very difficult to eliminate noise without smearing terrestrial detail. This is what sets this apart from normal astro work where land detail is usually not important.
Please check this 5D-mkIII evaluation for samples of what I am doing and some 100% crops showing before and after noise.

http://ben-egbert-photo.com/?page_id=1502

I also describe my workflow there. But after the write up, I have made a few refinements and am soliciting more with this massage.

I have found that luminance set around 60 and sharpening turned off is a good starting point using ACR (CS6). I then apply a medium Topaz NR for ISO1600 to get the rest.

I have tried just applying NR to the sky, but the foreground details need it just as much as the sky.

One recent article suggested not using any in-camera NR. The article was not clear enough to say if this referred to long exposure NR for raw images or simply JPG NR. What are your thoughts on this? My 1DS-mk3 requires long exposure nr to reduce amp glow. In fact amp glow is never totally eliminated at 30 seconds.

Here is a link to larger sizes of these images.


http://ben-egbert.smugmug.com/Landscapes/Stars/illuminated-by-the-moon/26272618_gTJH7c#!i=2341861361&k=T4hCLrP





sample moonlit landscape

  Canon EOS 5D Mark III    EF24-70mm f/2.8L II USM lens    30mm    f/7.1    13s    1600 ISO    0.0 EV  




Jan 29, 2013 at 05:48 PM
Eyeball
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p.1 #2 · Hi iso NR technique for night sky’s.


Hi Ben.

I have accumulated several different noise reduction packages (Topaz, Imagenomic, Nik) over the years as well as several different sharpeners. If you would like to make a raw file available, I would be glad to take a look at it and try to run you some comparative examples. PM if you wish. Just give me a day or two to run the samples.

The one sample of yours that I took a look at looked like it had pretty significant artifacts in the trees after the noise reduction.

One thing that occurred to me is if you are getting the best exposure possible when you take the shot. I can't be sure without seeing a raw file but it looks to me that in some of your examples, you are leaving a little too much of a cushion in the bright tones. My guess would be at least 10-15%. The more cushion you leave on the top-end, the worse the noise is going to be on the dark end.

Have you ever played around with Uni White Balance? It is a way to re-balance the in-camera histogram so it displays more-or-less true raw clipping instead of sRGB or AdobeRGB. You might want to experiment with it if you never have. On the 5D2, it is as simple as snapping a completely blown white image and using it to set a custom white-balance in-camera. I don't know if the procedures works on the 5D3 or not.

The bad news with Uni White Balance is that it will make the embedded Jpeg thumbnail appear green but the advantage is that your histogram will give you a truer view of when the raw file starts to clip.



Jan 29, 2013 at 09:39 PM
ben egbert
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p.1 #3 · Hi iso NR technique for night sky’s.


An attempt to share a raw via dropbox

https://dl.dropbox.com/u/77536572/130123-7626-5D%20Mark%20III.CR2



Jan 30, 2013 at 04:27 AM
Mr Joe
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p.1 #4 · Hi iso NR technique for night sky’s.


I'm interested in the results of the test. I do a lot of night shooting, but typically at ISO 100 or 200, with longer exposure times for cloud and star trails.


Jan 30, 2013 at 04:36 AM
morganb4
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p.1 #5 · Hi iso NR technique for night sky’s.


This is what I do in Lightroom.

1 Process colour & tonalities as desired
2 Sharpening off
3 Luminance and Detail sliders to max
4 Zoom to 200%, you should see some artefact in blank, detail free regions
5 Bring down detail slider until that artefact just disappears.
6 Bring Luminance slider back to Zero (i.e. max noise again), navigate to a detailed area of the image at 100% and increase luminance slider slowly until you have a good balance between the desired level of detail and noise.

If you don't set the detail slider properly first, its much less easy to get this balance and your sharpening will be less esasy.

If colour noise is an issue, I usually do a fairly liberal adjustment between points 5 and 6 - you don't need to be as exact.





Jan 30, 2013 at 06:07 AM
Eyeball
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p.1 #6 · Hi iso NR technique for night sky’s.


I was able to download the file, Ben. I probably won't be able to post any detailed comparisons until tonight but here are some preliminary thoughts:

- As I suspected, the raw file is very dark and possibly significantly underexposed depending on what you are after. I could only find one star that was clipped at the default exposure and that was only in one channel. Unless it is absolutely critical for you to not clip the stars, I think you would be doing yourself a favor to boost exposure. I find that it is sometimes even worth it to boost ISO, if necessary, in order to move that histogram to the right - as long as you are still at a native ISO for the camera.

- I use LR noise reduction quite a bit but for special cases like this where you need a lot of control differentiating between noise and detail, I think it is going to be a bit ham-fisted. I think this is the type of work that needs more specialized tools unless you are going to do multiple developments in LR and blend them in PS. Still checking though.

- I need to go back through your NR process to see if you mentioned it but when I need to use the specialized NR tools, I normally turn off the sharpening and noise sliders completely in LR. I think that helps the specialized tools understand the noise characteristics better.

I'll post later in the day with some examples.

Edited on Jan 30, 2013 at 02:02 PM · View previous versions



Jan 30, 2013 at 01:32 PM
Eyeball
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p.1 #7 · Hi iso NR technique for night sky’s.


morganb4 wrote:
This is what I do in Lightroom.

1 Process colour & tonalities as desired
2 Sharpening off
3 Luminance and Detail sliders to max
4 Zoom to 200%, you should see some artefact in blank, detail free regions
5 Bring down detail slider until that artefact just disappears.
6 Bring Luminance slider back to Zero (i.e. max noise again), navigate to a detailed area of the image at 100% and increase luminance slider slowly until you have a good balance between the desired level of detail and noise.

If you don't set the detail slider properly first, its much less easy to get this balance and
...Show more

Do you really mean to say to turn sharpening off (Amount set to 0) in step 2? Because if Sharpening is off, the Detail slider doesn't do anything. Or did you mean the "Luminance Detail" noise reduction slider?



Jan 30, 2013 at 01:44 PM
dgdg
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p.1 #8 · Hi iso NR technique for night sky’s.


I may be missing part of your point, so I apologize for anything I say that is over simplified.

Ben, can you take two photos, process, and then blend them with a mask? One focused and exposed for sky, then processed for noise and detail. Similarly one for land? Then combine with a mask.
If not, I find Lightroom focal adjustments work well on single images to adjust noise and sharpening preferentially in different areas.

My second image (link) labeled moonrise is two images. One image is for sky and one for land. Both processed separately, then combined via mask in photoshop. Both are sharp on my monitor with good detail and nr.
http://www.fredmiranda.com/forum/topic/1148433/0#10957256



Jan 30, 2013 at 03:01 PM
ben egbert
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p.1 #9 · Hi iso NR technique for night sky’s.


Eyeball wrote:
I was able to download the file, Ben. I probably won't be able to post any detailed comparisons until tonight but here are some preliminary thoughts:

- As I suspected, the raw file is very dark and possibly significantly underexposed depending on what you are after. I could only find one star that was clipped at the default exposure and that was only in one channel. Unless it is absolutely critical for you to not clip the stars, I think you would be doing yourself a favor to boost exposure. I find that it is sometimes even worth it to boost
...Show more

I have some over exposed as I was working out the exposure. But they were grossly overexposed. I had the camera from CPS loan and only had one clear night. It has been snowing like crazy since then and I have returned the camera. So no chance to repeat the test.

I have Neat image which I no longer use as it is not 64bit. I have Topaz which is the plug in I used. I don't have LR, but do have CS6 which I think has the same features via ACR.




Jan 30, 2013 at 04:13 PM
ben egbert
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p.1 #10 · Hi iso NR technique for night sky’s.


dgdg wrote:
I may be missing part of your point, so I apologize for anything I say that is over simplified.

Ben, can you take two photos, process, and then blend them with a mask? One focused and exposed for sky, then processed for noise and detail. Similarly one for land? Then combine with a mask.
If not, I find Lightroom focal adjustments work well on single images to adjust noise and sharpening preferentially in different areas.

My second image (link) labeled moonrise is two images. One image is for sky and one for land. Both processed separately, then combined via mask in photoshop.
...Show more


I typically don't blend because the light from a moonlight scene is typically fairly flat. IE, I usually don't have clipping. I also don't want the landscape to look too much like daylight, I want it to look dark but visible as it is in full moonlight.





Jan 30, 2013 at 04:15 PM
 

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ben egbert
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p.1 #11 · Hi iso NR technique for night sky’s.


morganb4 wrote:
This is what I do in Lightroom.

1 Process colour & tonalities as desired
2 Sharpening off
3 Luminance and Detail sliders to max
4 Zoom to 200%, you should see some artefact in blank, detail free regions
5 Bring down detail slider until that artefact just disappears.
6 Bring Luminance slider back to Zero (i.e. max noise again), navigate to a detailed area of the image at 100% and increase luminance slider slowly until you have a good balance between the desired level of detail and noise.

If you don't set the detail slider properly first, its much less easy to get this balance and
...Show more

I am going to try this. I set sharpening to zero for this type of shot and have worked only with the luminance slider. I assume you mean luminance detail.

I just tried it, much better than my results. Thanks for the tip. I was able to get the foreground noise good enough with this and then did the sky with Topaz medium to finish it off.



Jan 30, 2013 at 04:25 PM
Bifurcator
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p.1 #12 · Hi iso NR technique for night sky’s.


ben egbert wrote:
I am looking for strategies to deal with noise under the following conditions.
Moderate ISO, 800 to 3200. Longish exposures, between 10 and 30 seconds. ˝ to full moon for illumination with detailed landscape foregrounds.

I am familiar with astro techniques for stacking multiple images and using dark frame subtraction etc. This is different than what I am trying to achieve and is aimed at cleaning up a dark sky with little terrestrial detail.
I want clean sky and detailed foreground. It is very difficult to eliminate noise without smearing terrestrial detail. This is what sets this apart from normal astro
...Show more



I do essentially he same thing using the same tools. The difference is only in the settings and a fade step I think but I come out with a clean very detailed image.

http://tesselator.gpmod.com/Images/Temporary/130123-7626-5D_MarkIII.jpg
This is your image full sized image run through this script: http://tesselator.gpmod.com/Images/Temporary/My_Quickys.atn (the one called "sRGB, Save JPG")

Notice that I have the Topaz GUI pop up... That's so I can adjust the sliders to fit the image. In the case of your image the Overall strength was set to 30 or 35, darks were set to -.50, and the both the recover detail and the reduce blur were zeroed out.

If you need to recover the fine detail in the shrubbery after the NR step then you need to use the history brush at about 75% or so. Otherwise, you'll never be able to have shrubbery like that remain sharp with the captured amount of detail and also noise reduction - no matter which tools you use or how you capture and process the image. Well, a panorama could but I mean single exposures, etc..



Jan 30, 2013 at 05:32 PM
ben egbert
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p.1 #13 · Hi iso NR technique for night sky’s.


Thanks, looks good. I usually don't get into Topaz individual sliders, probably because I am mostly a landscaper who shoots at ISO100. But it looks like I need to revisit this.

The advice from morgan combined with this ought to provide even further improvements.

I also found one image from the night with higher exposure, I guess I flushed the others. I need to see if this helps.
Tried your script, I need to digest it a bit.



Jan 30, 2013 at 05:48 PM
dgdg
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p.1 #14 · Hi iso NR technique for night sky’s.


ben egbert wrote:
I typically don't blend because the light from a moonlight scene is typically fairly flat. IE, I usually don't have clipping. I also don't want the landscape to look too much like daylight, I want it to look dark but visible as it is in full moonlight.


Blending to account for clipping is not the issue here I agree. More making a composite from two photos.
You can certainly make the exposures look natural for land land sky. I guess I was trying to suggest shooting the land at low iso and longer exposure. You can process it for the darkness you like, but the iso will be low and you can make it crisp too. Then shoot your sky photo where shutter speed will be probably 1/25 or shorter and process it the best you can for noise. Depending on your image, you can do a manual mask or luminance mask to copy the land on top of your sky photo. I think this works well if I understand what your are wanting.



Jan 30, 2013 at 08:57 PM
ben egbert
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p.1 #15 · Hi iso NR technique for night sky’s.


The test was to see how much better the 5D-mk3 was than the 1DS-mk3. It was a test more than anything and I wanted to use ISO1600 which is where the 1DS-mk3 is too noisy for printing.

No matter what technique I use, it looks to me like the 1DS-mk3 is nearly as good at ISO1600 as the 5D-mk3. But from this post I have learned how to make both look better. I returned the 5D-mk3 and still have the 1ds3. I might have purchased a 5d3 had it been significantly better. I am still thinkinbg about a 6D for a backup and for high iso work.




Jan 30, 2013 at 09:22 PM
Bifurcator
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p.1 #16 · Hi iso NR technique for night sky’s.


ben egbert wrote:
Tried your script, I need to digest it a bit.


Cool. I think the best way to digest it is just to run it a few times. It does assume that you have Topaz Detail installed. Watch the script items execute (not button mode!) and click on & off the Preview check boxes in the Fade dialogues. When something pops up with a dialogue it usually means it's set about right but alterations are needed for different kinds of images - so try adjusting it. DeNoise is one that always needs to be adjusted - tho you can turn it off all together for ISO 100 images (depending what else you're doing to it). If you find one item to always be wrong (too high or low or whatever) stop the script, double click on that script item, and enter more appropriate settings. Once you click OK the new settings will be saved back to the script - quitting PS will save the script. If there's a step in the script you find unnecessary you can click it's Exe button to turn it off - be sure to turn off the fade for it as well. And likewise with turning On steps that are currently turned off.

The PS scripting system is pretty easy once you familiarize yourself with it - which just takes doing it a few times.

Have fun with it!




Jan 31, 2013 at 12:45 AM
ben egbert
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p.1 #17 · Hi iso NR technique for night sky’s.


Hi, I ran the script several times and used the preview to see what was going on. Topaz ran but did not show the dialogs, it just ran and finished. I have Denoize 5 so the 4 in the script failed.

It looks like you convert to jpg as a first step. Why is that?

I typically use Photopop for mine and then change to luminance and fade as required.



Jan 31, 2013 at 01:03 AM
Bifurcator
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p.1 #18 · Hi iso NR technique for night sky’s.


No, the first step (turned off) is to set the file to 16bit - just in case it was an 8bit file. I usually bring in the RAW files as 16bit ProPhoto and also open them as larger than they are - all through ACR settings. The resize just before the first Save sets it back to the original RAW size (of MY camera) and that Save saves it as a PSD file.

The three different Topaz Detail calls don't show the interface, just the Fade which comes after each. That's on purpose. If you decide you need the interface each time just click on the Show Dialogue button for the script item you want to see the dialogue for.

To get DeNoise 5 in there disable the v4 one, select it in the script list, click the Record button, and execute your V5 one. After it finishes click on the stop recording button and move the new script entry into place if it's not already - either just above or just below the old one.

The entire script as I use it and as it should appear for you, looks like:







Jan 31, 2013 at 01:20 AM
ben egbert
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p.1 #19 · Hi iso NR technique for night sky’s.


Ok, thanks, I will give it a try tomorrow.


Jan 31, 2013 at 02:33 AM
Eyeball
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p.1 #20 · Hi iso NR technique for night sky’s.


Well, this probably won't be very helpful but here is what I was able to do with some limited time this evening.

First, I'll just repeat again that I think you might want to try increasing exposure. You can always pull the exposure back down in post so it looks like you want but by exposing more to the right, you will get more tonal values out of the noise floor. You may run some risk of clipping the stars and losing some subtle color in them but as it is now you are probably losing that subtle color anyway with your noise reduction.

Here is just a reminder of how dark this image is using linear gamma of 1, the "natural" gamma of the raw file. Those darkest 2 or 3 stops of the image have many fewer tonal levels than the brightest stops. I'm sure you've probably read several of the "Expose to the Right" articles on the web, Ben, so I won't repeat all that here but just take this as a reminder. I think it could really help this type of photography and it may be the reason you are seeing different results from some of the sites you referenced.







Here is a comparison of different Noise Reduction packages. It is not perfect by a LONG shot but maybe it will give you a rough idea. Comparing NR packages is much like comparing raw developers - there is no common baseline for types of settings and setting amounts so it's almost impossible to do an apples-to-apples comparison. It's also easy to favor the package you use most because you are more familiar with its controls and how it works. In my case, that would probably be Imagenomic's Noiseware although these days I really use Lightroom most of the time.

I tried to select 3 representative patches from your image: dark blue sky, clouds/sky/mountain, and some foreground trees/brush. Everything was ran through ACR for raw development but ACR noise reduction and sharpening were set to zero for all tests except the ACR NR sample.







All of these packages have a variety of settings that can be tweaked and then you can do selective masking like you're looking at with BIF so it is almost certain that none of the samples above reflect the best of what could be accomplished with each package. I obviously haven't made the case but I still feel that you are going to be able to achieve better results with a specialized package over ACR/LR, particularly when you start adding sharpening but I could be wrong. Perhaps if someone wants to give LR or ACR their best shot, I will do a "best shot" approach with one of the other packages and we can compare. I may not have time to do that until the weekend though.



Jan 31, 2013 at 03:37 AM
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