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Long Exposure Noise Reduction

The D30 has a built-in noise reduction system which only takes effect if enabled (custom function 1) and if the exposure is longer than one second. The following samples taken of the same low light scene were taken at the full range of sensitivities first with noise reduction switched off then with noise reduction enabled. A fairly good evaluation of "Long exposure vs. High ISO".

ISO 100, 13 sec, F14 ISO 100, 13 sec, F14, Noise Reduction
ISO 200, 6 sec, F14 ISO 200, 6 sec, F14, Noise Reduction
ISO 400, 3.2 sec, F14 ISO 400, 3.2 sec, F14, Noise Reduction
ISO 800, 1.6 sec, F14 ISO 800, 1.6 sec, F14, Noise Reduction
n/a
(not longer than 1 second)
ISO 1600, 0.8 sec, F14 ISO 1600, 0.8 sec, F14, Noise Reduction

I have to say that the ISO 100, 13 second exposure even without noise reduction is fairly clean, yes there's some visible noise but far less than we'd expect for such a long exposure. With noise reduction enabled the image is clean without too much loss of detail. At higher sensitivities noise becomes a little more of an issue although still manageable.


Parameters

The D30 features up to three "sets" of camera parameters which control the cameras image processing algorithms. Each set can be made up of any combination of a -1,0,+1 (Low, Normal High) value for Contrast, Sharpening and Colour Saturation. By default the camera uses a "Standard" set which has neutral (0) settings for each parameter, using the supplied TWAIN driver you can add up to three other sets (this is the ONLY way to change these parameters). Below we've provided a set of samples using different parameter settings. Camera settings were: ISO 100, Aperture Priority, F8.0, 1 second exposure (remotely fired), Auto White Balance, 28 - 70 mm F2.8 L lens.

Parameters: Contrast


Majority of pixels level 11 - 217
Contrast -1, Sharpening 0, Saturation 0

Majority of pixels level 11 - 225
Contrast 0, Sharpening 0, Saturation 0 (Standard)

Majority of pixels level 11 - 236
Contrast +1, Sharpening 0, Saturation 0

Looking at D30 samples it's obvious that the D30 does all it can to preserve the bottom end of the luminosity scale, this can be seen in the Normal image, no pixels are absolutely black but rather ramp up from somewhere above level 11, the rest of the luminosity range is represented fairly evenly without blowing out any detail. Contrast adjustment seems to mostly effect the top end of the luminosity scale, thus images don't look any "darker" at contrast+ but some of the highlight detail has been blown out.

Parameters: Sharpening

Contrast 0, Sharpening -1, Saturation 0
Contrast 0, Sharpening 0, Saturation 0 (Standard)
Contrast 0, Sharpening +1, Saturation 0
Standard + Photoshop Unsharpen Mask 200%, radius 0.6, threshold 2

Canon seem to have taken a "stance" on internal sharpening, the D30 appears to perform only a very slight sharpen at the Standard setting. When the first sample images were published many people criticized them for being "Soft", I personally would support Canon's choice, images come out looking much more natural (photographic) with no nasty sharpening errors, jaggies or "halos" around detail. This of course gives YOU the choice to sharpen the image further if you wish, but you always have that unspoiled original.

Pushing sharpening to +1 doesn't make a huge amount of difference, and that's a shame because some people will prefer to be able to get sharp images immediately out of the camera (the detail is there).. Maybe we could see a +2 or +3 setting in a firmware update?

The last sample above was sharpened in Photoshop using what would normally be a hugely aggressive sharpen of 200%, but on the D30 it just brings the images up to what we'd expect of a high internal camera sharpening.

Parameters: Colo(u)r Saturation

Measured colour:
  Red Green Blue
Red patch 62% 17% 17%
Cyan patch 12% 48% 72%
Yellow patch 66% 62% 11%
Contrast 0, Sharpening 0, Saturation -1
Measured colour:
  Red Green Blue
Red patch 66% 16% 16%
Cyan patch 9% 49% 76%
Yellow patch 67% 63% 7%
Contrast 0, Sharpening 0, Saturation 0 (Standard)
Measured colour:
  Red Green Blue
Red patch 71% 13% 14%
Cyan patch 4% 49% 81%
Yellow patch 69% 68% 1%
Contrast 0, Sharpening 0, Saturation +1

Again, another very neutral "Standard" setting from Canon, I personally preferred the colour of Saturation +1 straight out of the camera, it's not overly saturated, you're not loosing any detail and the colours are more "pleasing" (closer to the S1 Pro - still not quite that good though). I had a parameter set programmed with Saturation +1 and used it most of the time.

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