How to process night sky shot with Nikon NEF?


#1

Hi folks,

I just started learning to use RT. I have this night starry sky picture taken with Nikon D810, with Landscape profile selected and WB set to about 2700K. I shot it with both RAW (NEF) and JPG. I like the JPG look, want to get a little more details from the dark area from the RAW file, and darken a little the mountain peaks area. How do I go about it? There are so many controls and adjustments in RT, I’m not sure where to start…

thanks,

Jason

The RAW file is here:
DSC_2391.NEF (31.6 MB)


(Mica) #2

Hi @seafan

There are several ways to go about this:

  • Exposure > Tone curve
  • Exposure > Highlights and Shadows
  • Exposure > Exposure > Black/Shadow Compression/Contrast
  • Exposure > Lab* Adjustments (Set Curves L to Custom and adjust the curve

I’d recommend that you spend some time playing with the noise reduction as well. Perhaps @Morgan_Hardwood can suggest some good noise reduction settings for this image.

Looking at your exposure settings, there are a few things that you could’ve done while capturing to make life easier. Get a cable/remote release, set your camera to Bulb, and then use an exposure time longer than 30 seconds. This will allow you to use a lower ISO, which will help eliminate the noise present in the shadows.

You could also shoot multiple exposures, one for the sky and one for the shadows, then blend them in an image editor like GIMP.


(Pat David) #3

First of all, wow that’s a stellar (pun intended) image you’ve got there! :smiley:

If you haven’t had a chance yet, give this section of rawpedia a read:

http://rawpedia.rawtherapee.com/The_Image_Editor_Tab#Eek.21_My_Raw_Photo_Looks_Different_than_the_Camera_JPEG

There may be a DCP for your camera already (not sure, but maybe!). Otherwise, what @paperdigits already said. Perhaps a touch of tonemapping or even simply raising shadows and increasing their tonal width a bit will help with details there.

I’m assuming you were also thinking about darkening the sky a little just around the mountain peaks as well? Not sure if it’s best approached in RT, or maybe better in something like GIMP with some masking.


(Shreedhar Inamdar) #4

Here is how I used RT on this image.

  1. In color management tab, enable both tone curve and Look Up Table (the dcp file mentioned by @patdavid for D810 is thereby loaded in RT. This gives starting point as your camera JPG)
  2. Change White balance based on snow on the mountain
  3. Changed the Demosaicing to Immse (it doesn’t make much difference though)
  4. Use the LH (lightness depending on Hue) curve of the LAB tab to reduce luminescence of the area about the mountain.
  5. Use the final touchup tab of Wavelet Levels and adjust the curve so that details in the sky are enhanced.
    DSC_2391.jpg.out.pp3 (10.2 KB)
    Final Image:

    Of course, the details like rocks in the foreground are lost but then we can export two copies and merge in GIMP to recover them. I did not do it because you wanted to know how to use RT on this image. Cheers.

(Guillaume Castagnino) #5

Here is what you can get from details for example:

But there is not much to recover in fact, if the goal was to have details in dark areas, the picture is heavily underexposed. The stars are not even a little clipped. So the dark area are very blurry and noisy.

After enabling LMMSE that deals better with high noise image, and loading the bundled DCP profile for your camera, I corrected the exposure (+1.7), enabled some noise reduction, and then played with the L* curve in “LAB adjustment” panel + a bit on tonal compression.
The blue cast is not the same as in the jpeg OOC, but this can be changed too.

DSC_2391.NEF.pp3 (9.9 KB)


(Hermann-Josef) #6

Hi,

just a naive question not related to RT, but on how this image was obtained.

The stars are perfectly imaged and not trailed. This implies to me that the camera was guided with the siderial motion. But how can then the landscape be correctly expose, i.e. not trailed? How can the Milky Way be properly exposed at the same time with the landscape?

Hermann-Josef


(Morgan Hardwood) #7

But they do trail.

30s at 14mm (114° diagonal field of view).


#8

Hi Jossie,

Like Morgan said, the stars did trail a little, that’s why I didn’t want to expose more than 30 sec as paperdigits suggested, as I don’t like the trailed look.


#9

Hi guilc,

Thanks for taking the time to process the file. my goal was just to get a little more details of the few rocks in the front, not the dark areas on the right.

it was a very starry night as I remember it, but the picture shows even more stars than I thought there were. so I have a question to all: how to tell if all those white dots were stars, or some kind of noise?


#10

Hi shreedhar,

could you please let me know how to load the DCP for Nikon D810? I can’t seem to load it:

if you compare yours and the picture processed after yours, most of the stars are not visible in your picture. how to avoid that?

My goal is to have a darker sky like yours, with all the stars showing like that in the other picture.


(Shreedhar Inamdar) #11

Hi @seafan. I am assuming that you have the RawTherapee 5 installed. In the same tab as you have shown, either click on custom menu (it will take you to the folder which keeps all the .dcp files and choose the one having name Nikon D810, or click on Auto-matched camera profile button and then activate the tone curve and Look Table (it will automatically choose the .dcp file from the above mentioned folder for you).

I will try to process it again and see if you can keep the stars and darken the sky. It is a very nice image. Cheers.


(Hermann-Josef) #12

Thanks for showing me the small trails. I only looked at the posted images and not the original. Reaching a depth to see the Milky Way in a 30 second exposure is fascinating.

This is a really impressing image! Congratulations.

Hermann-Josef


(Morgan Hardwood) #13

RawTherapee 5.1 coming out today has a DCP for the D810, so you will be able to click “Auto-matched camera profile”. In the meanwhile you can download it directly from https://github.com/Beep6581/RawTherapee/raw/dev/rtdata/dcpprofiles/NIKON%20D810.dcp


(Shreedhar Inamdar) #14

Here is my attempt at exporting two files from RT and merging them in GIMP. (I am sure, you can do a better merge!!)

@Morgan_Hardwood RT5.0-r1-gtk3 also has D810 profile preloaded.


#15

Thanks for your replies.

Hi Morgan,

RT5.1 is out? on their download page, I still see only RT5.0. Is there a link for RT5.1?

GIMP sounds like a good tool. is it used for blending multiple pictures? does it have layer mask like in PS?

I used your link to download the DCP for Nikon 810:

the image looks like this:

notice the mountain top area is much brighter than the JPEG image I posted first. Is it supposed to look the same?

Shreedhar,

I like your processed image, hat’s closer to what I witnessed that night in Patagonia. could you pls share the RT pp3 file of the images that you later combined in GIMP?


(Morgan Hardwood) #16

It will be later today.


(Morgan Hardwood) #17

No, it is not the DCP’s job to make your image look like your out-of-camera JPEG. The DCP’s job is to produce colors which are accurate.
See http://rawpedia.rawtherapee.com/The_Image_Editor_Tab#Eek.21_My_Raw_Photo_Looks_Different_than_the_Camera_JPEG


(Shreedhar Inamdar) #18

Here they are RT pp3 files and respective images:
DSC_2391.jpg.out.pp3 (10.3 KB)


DSC_2391-1.jpg.out.pp3 (10.3 KB)

The dark image was the top layer and used layer mask for the area above the mountains. Reduced the opacity of the top layer till I got the required darkness. After merging down the layers, also used a little bit of Tone mapping from G’MIC.

@seafan Check the profiles you are using (top right hand corner pull down menu). It might be set to Default. Put it to Neutral profile (from the pull down menu) and then apply the camera profile. You should get a darker image.


#19

A subdued way in RT with the tone mapping tool.

DSC_2391.jpg.out.pp3 (11.8 KB)


#20

Here’s another way in RT with the same tone mapping settings, with different color and exposure curves.

DSC_2391-4.jpg.out.pp3 (12.1 KB)