• site home
  • blog home
  • galleries
  • contact
  • underwater
  • the bleeding edge

the last word

Photography meets digital computer technology. Photography wins -- most of the time.

You are here: Home / The Last Word / Nikon D810 noise reduction raw processing

Nikon D810 noise reduction raw processing

August 20, 2014 JimK Leave a Comment

Yesterday I reported on some of the processing the D810 does to raw files, apparently in an attempt to reduce noise. A few weeks ago, I published these curves which look at dark-field noise vs shutter speed with the in-camera long exposure noise reduction on and off.

Long exposure noise reduction on
Long exposure noise reduction on
Long exposure noise reduction off
Long exposure noise reduction off

You will note that there is some processing taking place between (inclusively) 1/4 second and 1 second, that looks to be similar whether long exposure noise reduction is turned on or off.

You will also note that the long exposure noise reduction starts at 1.3 seconds, and that its effect is to increase the standard deviation of the dark-field noise, not decrease it, as you’d expect.

Let’s look at the histograms of the 1/5 second image and the 1/4 second one. It doesn’t matter if long exposure noise reduction is turned on or off; they look like this:

 

1.5 second
1/5 second
1/4 second
1/4 second

What are the differences? First, there’s that double filled histogram near the black point. That’s obvious, but probably unimportant. The big news is not in the graphical histograms, but in the numbers to their right, particularly the maximum values. The transition from 1/5 to 1/4 second invokes some kind of processing that has the effect of reducing or eliminating outlier pixels.

You’d think that something like that could affect the ability of the image to hold detail, but it doesn’t seem to hurt materially. Here are the spectra of the two images:

 

1/5 second
1/5 second
1.4 second
1/4 second

Now let’s look at what’s going on as the shutter speed changes from 1 second to 1.3 second with long exposure noise reduction turned on. Here are the relevant histograms:

 

1 second
1 second

 

1.3 seconds
1.3 seconds

You can see the bulk of the histogram getting broader as the shutter speed gets longer, which is what the graph at the top of this post indicated. But note the maxima: the 1,3 second image has a significantly lower maximum than the 1 second image.

Plotting the maxima rather than the standard deviation across the entire range of shutter speeds tells the story, albeit noisily.

D810MaxRNvsshutterNRoff D810MaxRNvsshutterNRon

 

Except for two green channel maxima, long exposure noise reduction substantially reduces the values of the worst case (hot) pixels.

The maximum is not the best measure for hot pixels; the 99th percentile, or even the the 99.9th percentile, would be better. However, Rawdigger doesn’t — yet — give you that information, and I don’t think this is important enough to write a Matlab script to do the job. (If someone wants it done, sing out and I’ll give it a shot.)

Now let’s look at the spectra of those two exposures:

1 second
1 second
1.3 seconds
1.3 seconds

The low pass spatial filtering component of the D810’s long exposure noise reduction appears to be independent of shutter speed, at least in the range between 1.3 seconds and 15 seconds.

The Last Word

← Nikon D810 long exposure noise reduction Nikon D810 high-ISO noise reduction →

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

July 2025
S M T W T F S
 12345
6789101112
13141516171819
20212223242526
2728293031  
« Jun    

Articles

  • About
    • Patents and papers about color
    • Who am I?
  • How to…
    • Backing up photographic images
    • How to change email providers
    • How to shoot slanted edge images for me
  • Lens screening testing
    • Equipment and Software
    • Examples
      • Bad and OK 200-600 at 600
      • Excellent 180-400 zoom
      • Fair 14-30mm zoom
      • Good 100-200 mm MF zoom
      • Good 100-400 zoom
      • Good 100mm lens on P1 P45+
      • Good 120mm MF lens
      • Good 18mm FF lens
      • Good 24-105 mm FF lens
      • Good 24-70 FF zoom
      • Good 35 mm FF lens
      • Good 35-70 MF lens
      • Good 60 mm lens on IQ3-100
      • Good 63 mm MF lens
      • Good 65 mm FF lens
      • Good 85 mm FF lens
      • Good and bad 25mm FF lenses
      • Good zoom at 24 mm
      • Marginal 18mm lens
      • Marginal 35mm FF lens
      • Mildly problematic 55 mm FF lens
      • OK 16-35mm zoom
      • OK 60mm lens on P1 P45+
      • OK Sony 600mm f/4
      • Pretty good 16-35 FF zoom
      • Pretty good 90mm FF lens
      • Problematic 400 mm FF lens
      • Tilted 20 mm f/1.8 FF lens
      • Tilted 30 mm MF lens
      • Tilted 50 mm FF lens
      • Two 15mm FF lenses
    • Found a problem – now what?
    • Goals for this test
    • Minimum target distances
      • MFT
      • APS-C
      • Full frame
      • Small medium format
    • Printable Siemens Star targets
    • Target size on sensor
      • MFT
      • APS-C
      • Full frame
      • Small medium format
    • Test instructions — postproduction
    • Test instructions — reading the images
    • Test instructions – capture
    • Theory of the test
    • What’s wrong with conventional lens screening?
  • Previsualization heresy
  • Privacy Policy
  • Recommended photographic web sites
  • Using in-camera histograms for ETTR
    • Acknowledgments
    • Why ETTR?
    • Normal in-camera histograms
    • Image processing for in-camera histograms
    • Making the in-camera histogram closely represent the raw histogram
    • Shortcuts to UniWB
    • Preparing for monitor-based UniWB
    • A one-step UniWB procedure
    • The math behind the one-step method
    • Iteration using Newton’s Method

Category List

Recent Comments

  • Michael Angelo on Nikon Z7 focus shift shooting
  • Erik Kaffehr on Visualizing lens aberrations — why do it?
  • Eugene on Don’t fixate on the bad stuff
  • Jonby on How focus-bracketing systems work
  • JimK on Of fidelity, photography, audio, and wine
  • JimK on Of fidelity, photography, audio, and wine
  • AVN on Of fidelity, photography, audio, and wine
  • Markus on In photography, and in life, work and joy can, and should, coexist
  • JimK on Fuji 120/4 GF at 1:1 with tubes — visuals
  • Christopher Roberton on Fuji 120/4 GF at 1:1 with tubes — visuals

Archives

Copyright © 2025 · Daily Dish Pro On Genesis Framework · WordPress · Log in

Unless otherwise noted, all images copyright Jim Kasson.