Sharpening (Custom setting 23)

Via custom setting 23 you can select from four levels of sharpening: Normal, Low, High and None.

Settings: ISO 125 / Exposure: 1/13s, F8.0 / Tone: Auto / Colorspace: sRGB / Large FINE JPEG.

CSM 23-0: Normal

CSM 23-1: Low

CSM 23-2: High

CSM 23-3: None

At anything above Low the sharpening algorithm has a tendency to introduce sharpening artifacts such as white halos around black lines. Generally speaking the Low setting seems to offer the best balance between sharpness and low artifacts, you can always sharpen up the image later (using an unsharpen mask) in Nikon Capture 2 or a third party application such as Photoshop. Canon EOS-D30 owners would probably recognise Low or None as closest to its smooth artifact free images.

Tone (Custom setting 24)

Through custom setting 24 you can select one of five custom tone curves: Auto, Normal, Contrast -, Contrast + and Custom. Custom curves can only be programmed through the Nikon Capture 2 application. Each of these settings applies a different "correction curve" to the RAW data before it's turned into a JPEG / TIFF. (In RAW mode the Tone is recorded in the header of the RAW file but image data is not modified).

Settings: ISO 125 / Sharp.: Normal / Colorspace: sRGB / Med. FINE JPEG.

CSM 24-0: Auto, 1/13s, F8.0
CSM 24-1: Normal, 1/15s, F8.0
CSM 24-2: Contrast -, 1/15s, F8.0
CSM 24-3: Contrast +, 1/20s, F8.0

Generally speaking the Auto setting produced the best results, with the camera selectively choosing (this is an assumption base on observation) either Normal or Contrast - curves. Contrast - is useful if you're going to be post-processing the images as it produces the "flattest" image without clipping the low or high end of the grayscale.

Colorspace (Custom setting 32)

After the confusion over the D1 and it's colorspace (which turned out to be somewhere near to NTSC, but not exactly) Nikon took the excellent decision to provide two selectable calibrated options for colour output. Via custom setting 32 you can now select to store images into the sRGB or the Adobe RGB (1998).

Below is a chromaticity diagram (CIE gamut), the main coloured area represents approximately the range of colour which the human eye can resolve. Inside this you can see three triangles, the two we're interested in are Adobe RGB (1998) and sRGB.

Put simply sRGB was a standard developed mostly by HP and Microsoft, it's the most common (and default) colorspace for PC computer monitors and is the colorspace assumed by many applications (including web browsers). sRGB has a limted gamut (range of colours) but would be the common choice for those shooting for the web.

Adobe RGB (1998), defined by Adobe Corp. is the most common colorspace used by professional graphics designers, publications and digital imaging professionals, it provides a much wider gamut (range of colours), it has a much better ability to capture very deep or bright colour. HOWEVER unless your photo application knows the image has been recorded in the Adobe RGB colourspace it will look 'dull' on an sRGB device and will contain incorrect color casts in certain colors (such as greens looking too yellow, etc).

We shot the same scene, first in sRGB colorspace and then in Adobe RGB. On your monitor (probably) the sRGB image will have colours that look more saturated, vivid and accurate. The Adobe RGB image will look dull (because your browser doesn't know that it's not in sRGB colorspace). If you download the Adobe RGB JPEG, load it into an application that supports color profiles (such as Adobe Photoshop) and then 'Assign Profile' -> 'Adobe RGB (1998)' you'll see colours in their full glory.

Settings: ISO 125 / Exposure: 1/15s, F8.0 / Sharp.: Normal / Tone: Auto / Large FINE JPEG.

CSM 32-0: sRGB colorspace	CSM 32-1: Adobe RGB (1998) colorspace

The crop directly below the images shows how Adobe RGB is the professionals choice, it's far better at maintaining deep or bright colours (because of its wider colour gamut), the sRGB image has already 'blown out' this bright colours.

Here's my nag about this option: The selected colourspace isn't written into the JPEG/TIFF header in any standard way. That is if you drag a D1x JPEG into Photoshop it doesn't know what colourspace it was shot in and will assume sRGB, you'll have to either set your working profile to Adobe RGB (assumed) or assign each image as you load it. HOWEVER, resave the image in Nikon Capture 2 or convert a RAW file and it will be tagged with the colour profile and Photoshop can automatically assign the correct profile.

Hue Adjustment (Custom setting 33)

The Hue Adjustment option allows you to make very subtle changes to the colour balance of the output image. The manual describes this feature like this "Although the camera's sophisticated metering and white balance are capable of reproducing colors accurately under almost all lighting conditions, you may want to adjust hue to cope with unusual lighting conditions or to deliberately introduce a color cast into the image".

A value of 3 is 'neutral' (the default), values below this will push colours towards purple, values above this push colours towards yellow. Directly below the thumbnail for the image is its RGB histogram map.

Settings: ISO 125 / Exposure: 1/20s, F8.0 / Sharp.: Normal / Tone: Auto / Colorspace: sRGB / Med. FINE JPEG.

33-0: Hue 0 (Purple cast)	33-0: Hue 1	33-0: Hue 2
	33-0: Hue 3 (Normal)
33-4: Hue 4	33-5: Hue 5	33-6: Hue 6 (Yellow cast)