Home · Register · Search · View Winners · Software · Hosting · Software · Join Upload & Sell

Moderated by: Fred Miranda
Username   Password

  New fredmiranda.com Mobile Site
  New Feature: SMS Notification alert
  New Feature: Buy & Sell Watchlist
  

FM Forums | Post-processing & Printing | Join Upload & Sell

1      
2
       end
  

Archive 2013 · Hi iso NR technique for night skyís.
  
 
Bifurcator
Offline
• • • • •
Upload & Sell: On
p.2 #1 · p.2 #1 · Hi iso NR technique for night skyís.


Hey, pretty cool! Thanks from me for sure...

Eyeball wrote:
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
...Show more



Jan 31, 2013 at 12:13 PM
Eyeball
Online
• • • •
Upload & Sell: On
p.2 #2 · p.2 #2 · Hi iso NR technique for night skyís.


On thing I forgot to mention: I was pretty impressed with Topaz. I have used it before to correct banding noise on my 5D2 but I had never used it much on this type of image. One negative thing I noticed though is that it seems pretty easy to smooth the sky to the point that some posterization effects start to appear. I can even see a hint of that in the sample I posted if I look at my display from the side. Just something you might want to be on the lookout for if using Topaz.


Jan 31, 2013 at 01:03 PM
ben egbert
Online
• • • • •
Upload & Sell: On
p.2 #3 · p.2 #3 · Hi iso NR technique for night skyís.


Eyeball wrote:
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
...Show more

I found an image from the night that was exposed nearly to clipping in the snow areas. You are correct, it cleaned up better. I would have needed to use a sky from another image and it needed a lot of post processing darkening.

Next full moon I will do some experimenting with exposure.

Thanks for your work, I need to play with Topaz denoize which is the only plug-in I have at the moment that runs at 64bit.






a brighter image from the night

  Canon EOS-1Ds Mark III    EF24-70mm f/2.8L II USM lens    70mm    f/4.0    15s    1600 ISO    0.0 EV  




Jan 31, 2013 at 02:04 PM
ben egbert
Online
• • • • •
Upload & Sell: On
p.2 #4 · p.2 #4 · Hi iso NR technique for night skyís.


The tricks and techniques suggested here work for the 1DS-mk3 as well. I am finding the ACR NR tips and the Topaz tips working fine. Also the tip for a brighter exposure. Although I will need to really think that one through as far as brackets are concerned.

One other thing, This location is not ideal. To freeze stars, you ultimately need to stop down and then DOF is limited. You need a place without much near detail, especially dark detail.

One of the best places I found was in Zion where the bright reflective rock made a great foreground.




Jan 31, 2013 at 06:32 PM
morganb4
Offline
• • • • •
Upload & Sell: Off
p.2 #5 · p.2 #5 · Hi iso NR technique for night skyís.


Are you hitting the hyperfocal distance? Whilst a smaller aperture gives great focus, it also gives rise to greater diffraction which works against your detail. Is there any value in stopping down past f5.6, given that the sweetspot of any lens is usually ~ 2 stops above its widest aperture.

Thats movement on the stars, less to do with mis-focus. I dont see how stopping down much more will help.

Remember WB can really affect the level of noise in an image, try it and see. Have you considered a differential WB for sky and foreground, it would also add a more appealing contrast (IMO).

I will take noise over motion blur any day. Noise I can deal with, no detail I cant. That last image like to have seen at 5.6 and 2 stops less shutter.



Jan 31, 2013 at 10:19 PM
morganb4
Offline
• • • • •
Upload & Sell: Off
p.2 #6 · p.2 #6 · Hi iso NR technique for night skyís.


Are you hitting the hyperfocal distance? Whilst a smaller aperture gives great focus, it also gives rise to greater diffraction which works against your detail. Is there any value in stopping down past f5.6, given that the sweetspot of any lens is usually ~ 2 stops above its widest aperture.

Thats movement on the stars, less to do with mis-focus. I dont see how stopping down much more will help.

Remember WB can really affect the level of noise in an image, try it and see. Have you considered a differential WB for sky and foreground, it would also add a more appealing contrast (IMO).

I will take noise over motion blur any day. Noise I can deal with, no detail I cant. That last image like to have seen at 5.6 and 2 stops less shutter.

Also SmartSharpen can correct very minor amounts of movement blur. One could apply it as a fully masked layer and just paint back in the stars. Would take ages but its exactly the kind of OC thing that I would do.



Jan 31, 2013 at 10:20 PM
ben egbert
Online
• • • • •
Upload & Sell: On
p.2 #7 · p.2 #7 · Hi iso NR technique for night skyís.


I want the stars sharp so I can't do hyperfocal. I focus specifically on either a star or a very distant light.

For serious work, I need a shorter shutter or a wider lens to stop star motion. This was not serious work, I wanted to look strictly at noise and simulated shots that would produce it.

Here is my decision.: Just placed the order for a 5d-mkIII


1.After showing my results comparing the 5d-mkIII against the 1DS-mk3 and getting these tips on NR, it looks like I can push both the 5d-mkIII and 1ds-mk3 to ISO1600, so thatís not a deal maker, but the 5D-mkIII long noise amp glow is better and probably has more margin.

2.The 6D could never replace the 1DS-mk3, but the 5D-mkIIL can. This will allow me to sell the 1DS-mk3 and recover the cost difference between 6D and 5d-mkIII.

3.I am pretty sure I would not be happy with a 6D after using a 1 series.

4.The whole idea is to have enough funds left for the high MP camera at the next release cycle. But that could be 2-3 more years and I donít have that much time left to fritter away.

5.The real deal maker for me was the improved live view. This has been a real problem for me doing critical TSE lens focus on the 1DS-mk3 and for critical focus for night shots.





Jan 31, 2013 at 11:22 PM
morganb4
Offline
• • • • •
Upload & Sell: Off
p.2 #8 · p.2 #8 · Hi iso NR technique for night skyís.


New toy = win! but did you consider a D800? Supposed to really good for this kind of stuff? All depends on your existsing level of canon glass commitment I suppose.


Jan 31, 2013 at 11:38 PM
ben egbert
Online
• • • • •
Upload & Sell: On
p.2 #9 · p.2 #9 · Hi iso NR technique for night skyís.


I will stick with Canon. I think lenses are more important than resolution, especially corner sharpness. The 14-24 is great, but I really like my 17TSE and 24-70 f2.8mk2.



Feb 01, 2013 at 12:48 AM
 

Search in Used Dept. 



hugowolf
Offline
• • •
Upload & Sell: Off
p.2 #10 · p.2 #10 · Hi iso NR technique for night skyís.


ben egbert wrote:
I will stick with Canon. I think lenses are more important than resolution, especially corner sharpness. The 14-24 is great, but I really like my 17TSE and 24-70 f2.8mk2.

And there is the D800 live view that you would have to work with.

Brian A



Feb 01, 2013 at 12:54 AM
ben egbert
Online
• • • • •
Upload & Sell: On
p.2 #11 · p.2 #11 · Hi iso NR technique for night skyís.


The most impressive feature to me on the 5D-mkIII was live view. If I still had my 500F4 and doing birds I might have been impressed with AI servo focus tracking. The 1DS-mk3 is no slouch but the 5D-mkIII is supposed to be better.




Feb 01, 2013 at 01:15 AM
Alan321
Offline
• • • • •
Upload & Sell: Off
p.2 #12 · p.2 #12 · Hi iso NR technique for night skyís.


Great lenses cannot overcome a crappy sensor and at several stops below mid-tone the 5D3 has a crappy sensor. Look for comparisons with the D800 to see where I'm coming from with that statement.

The 5D mark III is not particularly good at letting you retrieve clean image data out of deep shadows / dark areas. In fact it is pretty poor. Mind you, even the D800 starts looking poor at high ISO. Because the camera is so bad in that regard you need to consider increasing exposures and give the NR software a fighting chance. It will make a huge improvement if you can do it without losing important highlight data.

So if we can agree that with whichever camera we have it might help to increase the exposure, then we just need to consider how to achieve it:

A large aperture (smaller f/number) would be great if you can do without as much DOF. It might also allow a lower/cleaner ISO and more dynamic range. You might be able to overcome the DOF limitation with a TS-E lens but it could be too hard to get the stars sharp as well as the ground in a wide angle image. Easier with a tele lens such as the TS-E 90 or even the 45 than with a 17 or 24.

A longer shutter exposure would cause more obvious star trails. On a windy night the clouds and trees would show signs of motion blur too. Therefore probably not much good.

With a few cameras I have found that simply increasing the ISO helps while retaining the same aperture and shutter speed. Even after reducing the image exposure to equivalent levels in post processing the shadows are far cleaner than capturing less exposure at lower ISO. In some ways this is counter-intuitive but it works if the scene does not have too much dynamic range that all needs to be captured.


The really tricky thing is knowing how far you can increase the exposure without doing damage to important highlight details. The in-camera histogram is borderline useless at default camera settings because it is so greatly affected by jpg camera settings even when taking raw files. You have to know how to work around the limitations but doing so will make the jpg previews look rather poor while improving the underlying raw data:

1. Use neutral profile; No hidden contrast or saturation enhancements are wanted.
2. Use minimum contrast to get data away from the edges of the histogram.
3. Use low saturation, for the same reason.
4. Don't use too much sharpness. Some helps you better assess focus but too much brightens small bright highlights enough to give a false impression of overexposure.
5. Use an appropriate WB. This can have a big impact on the histogram especially at the edges (bright and dark limits).
6. Use the R, G and B histograms to show individual channels. Forget about overall luminance and concentrate on the individual channels. It's the channels that burn out.
7. Apply the over-exposure blinkies. Preferably to a single colour channel that is most likely to blow out. In this case I'd expect the blue channel is at most risk. In another image it might be the red channel. Green is usually safer than red or blue.

The result so far will look rather bland but only in the LCD preview. Don't panic; the raw data is still there. If any of the preview image still looks overexposed then the capture probably really is at or near true overexposure - as in the bright details are about to be lost even in the raw data. If they are not showing signs of overexposure with this setup then it is safe to increase the exposure so go ahead and do it and shoot again.

8. If you are sufficiently familiar with this approach then it may suffice. Otherwise it is time to start throwing in some exposure bracketing.

9. If you are really keen then you can also look up uni-WB and find or create a settings file that works best for your camera. Image previews will look terribly green but the histogram will be as close as you'll ever get to representing what the sensor captured in raw data. To be honest, I tend to stop at step 8 rather than go all the way to using uni-WB. Nobody likes the look of uni-WB previews.

10. Know that most of these steps need to be undone in post processing.

Get hold of a utility called rawdigger to see what the raw data histograms really look like. Unfortunately it needs to run on a computer - great if you can do a tethered capture or upload in the field. Unfortunately it does not know exactly what the head room is for each camera but if you see peaks at the bright end of the raw histogram and there are no specular highlights in the scene then you know that something is being lost due to overexposure. It also helps by allowing you to develop a better feel for what the steps above do to your raw data.

- Alan



Edited on Feb 01, 2013 at 08:22 PM · View previous versions



Feb 01, 2013 at 06:47 PM
Alan321
Offline
• • • • •
Upload & Sell: Off
p.2 #13 · p.2 #13 · Hi iso NR technique for night skyís.


Eyeball wrote:
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?


He did mean the luminance sharpening amount. You are right about turning it off but the point was to start at zero and work up from there. It will not stay at zero - you know that because otherwise you would not be cleaning the image in the first place. However, I work the opposite way. With it still at 100% I wind it down until the noise gets too much in the low-detail areas and then work back up a little. Then I look for a part of the scene where important image detail is under threat and do further tweaking as required. Sometimes a compromise is needed.

Sometimes the excessive noise in the low-detail areas is more significant than the loss of detail in the high-detail areas, and sometimes it's the other way around. It becomes a judgement call but morgan's approach is the best I have come across to get good NR results out of lightroom or acr. It works a treat far more often than it fails, and if this method fails then you almost definitely need a dedicated noise reduction tool or some clever layer magic in Ps.


I generally leave the luminance detail slider at about 70. Small changes make little difference and aren't worth making. Big changes rarely help because the image would already be too far gone.

I have the luminance masking set at 20-30 to overcome the effects of sharpening on the sky and so on. It only needs to be higher if the ISO was quite high or the details greatly underexposed and then recovered with other tonal adjustments.

Frankly I haven't worked out what to do with the luminance contrast control and so I leave it at zero.


The colour NR amount needs to be non-zero to fix colour blotches and hot pixels in dark areas. The colour detail needs to be high to prevent colour blurring at edges but not so high that coloured snow forms. Both of these are best set while the luminance amount is high but not at 100% so that luminance noise is not dominating the colour noise but also so that the temporarily high luminance NR is not cleaning up the colour noise too (because that won't last when the luminance NR is decreased).

- Alan


Edited on Feb 01, 2013 at 07:21 PM · View previous versions



Feb 01, 2013 at 07:01 PM
Eyeball
Online
• • • •
Upload & Sell: On
p.2 #14 · p.2 #14 · Hi iso NR technique for night skyís.


Hey, thanks for that tip about rawdigger. I was a big fan of Rawnalyze but since Panopeeper passed away the updates stopped at about the 5D2 timeframe. Nice to know someone has picked up the baton - especially since with sophisticated raw developers like Lightroom, it is very difficult to determine what is truly clipped in the raw.


Feb 01, 2013 at 07:02 PM
Alan321
Offline
• • • • •
Upload & Sell: Off
p.2 #15 · p.2 #15 · Hi iso NR technique for night skyís.


rawdigger is nice but not yet perfect. Be aware that with Canon DSLRs you have a useful tool in Canon DPP that can improve rawdigger. Look at DPPs "raw luminance" histogram. Note the horizontal scale and the right edge of that histogram chart. If you can read a graph then you can figure out how much raw data headroom (in exposure values or stops) there is between raw data mid-tone and the maximum raw luminance value. e.g. It's about 3.8 stops for the 1D4 but it varies for each camera model. And it pretty much stays that way even as ISO goes up - only the dark end is lost to increasing noise and decreasing DR (well, close enough for laymen).

Anyway, knowing that actual luminance headroom as defined by DPP allows you to tweak the rawdigger histogram instead of using its default 3 stops. Then you'll know how much DR you've wasted by not fully exposing the bright details.

There is no Nikon equivalent. DPP is one of the very few programs to represent any sort of raw data histogram, but it would be even better with separate colour channels.

- Alan



Feb 01, 2013 at 07:32 PM
ben egbert
Online
• • • • •
Upload & Sell: On
p.2 #16 · p.2 #16 · Hi iso NR technique for night skyís.


Alan321 wrote:
Great lenses cannot overcome a crappy sensor and at several stops below mid-tone the 5D3 has a crappy sensor. Look for comparisons with the D800 to see where I'm coming from with that statement.

The 5D mark III is not particularly good at letting you retrieve clean image data out of deep shadows / dark areas. In fact it is pretty poor. Mind you, even the D800 starts looking poor at high ISO. Because the camera is so bad in that regard you need to consider increasing exposures and give the NR software a fighting chance. It will make a huge
...Show more


Good info here, I will check this out for future reference.

I would not change systems just for night photography. It's such a small part of what I do which is mostly daylight landscapes at ISO100. I do lots of blending, lots of bracketing and also use ND grads. In 5 years with the 1DS-mk3, I have not had a lot if issue getting shadow detail when needed and very little banding.

I have jazzed up the JPG settings mostly to help see the stinking LCD and judge sharpness. That will not be required with the 5D3



Feb 01, 2013 at 07:59 PM
Alan321
Offline
• • • • •
Upload & Sell: Off
p.2 #17 · p.2 #17 · Hi iso NR technique for night skyís.


Ben, I would not seriously recommend that you or anyone else change systems for any reason without a lot of thought and preparation, and you've got some nice Canon gear that cannot all be replaced. I mainly mentioned the D800 because someone else had, and because I had seen some comparisons that showed how poor the 5D3 was for the photo you were trying to take - with the intention of extracting detail from the dark depths. I suspect that it is worse than the 1Ds3.

I don't much like my D800E at high ISO but it is very very nice at low ISO. I imaging there will be a Canon equivalent before long and you can look forward to trying it out with those lenses.

It didn't occur to me until now to make another entry in my table about using a TS-E lens to let you get away with a larger aperture. Have you considered that option ?



Feb 01, 2013 at 08:15 PM
ben egbert
Online
• • • • •
Upload & Sell: On
p.2 #18 · p.2 #18 · Hi iso NR technique for night skyís.


My 17TSE at f4 is a great night image lens. Also, for serious night images, I like to find places like this where the natural reflection is good and there is not a lot of shadow detail to pull up.





  Canon EOS-1Ds Mark III    TS-E17mm f/4L lens    17mm    f/4.0    25s    800 ISO    0.0 EV  




Feb 01, 2013 at 08:33 PM
1      
2
       end




FM Forums | Post-processing & Printing | Join Upload & Sell

1      
2
       end
    
 

You are not logged in. Login or Register

Username   Password    Reset password