Image tone

The first option on the camera's record menu is 'Image Tone' this option is described in the *ist DS user manual as allowing you to 'Set the basic color tone of pictures'. The two options of Bright (default) and Natural appear to affect the base level of contrast, saturation and sharpness applied to the image. The Natural setting is described as 'images are finished naturally and suitable for retouching', this can be seen in the crops below, the natural setting has a slightly less contrasty tone curve, less saturated color and essentially no sharpening.

Image tone: Bright (default) Image tone: Natural

Image parameters

After the Image Tone setting you also have five levels of adjustment for contrast, saturation and sharpness.

Image parameter adjustments

  • Contrast: -2, -1, 0, +1, +2
  • Saturation: -2, -1, 0, +1, +2
  • Sharpness: -2, -1, 0, +1, +2

Contrast adjustment

Adjusting the tone alters the shape of the 'S curve' used to map the linear image data captured by the sensor into the correct gamma. A lower contrast setting maintains more of the original data's dynamic range but leads to a flatter looking image. A higher contrast setting stretches the grayscale (dark to light) of the image and could lead to clipping of both shadow detail and highlights.

  Contrast Luminosity histogram



Color saturation adjustment

Saturation adjustment allows you to control the strength of color in the final image. Lets get this out of the way straight away; Pentax you've got the default saturation up way to high, I can understand the idea behind 'Bright' (the default Image Tone setting; to provide images with some 'pleasing' punch straight out of the box) but it's just too much. I really can't imagine anyone wanting to use the +2 setting and the -2 setting doesn't go far enough.

  Saturation 100% crop


The *ist DS built-in image processing isn't the most elegant we've seen, it's more like that which we're used to seeing in compact prosumer cameras rather than digital SLR's. Sharpening is pretty much the same, the default setting is adequate but doesn't really deliver that crispness we're used to seeing, turning sharpening up doesn't help you end up with stronger sharpening halos and less defined detail.

Sharpness: -2
Sharpness: 0 (default)
Sharpness: +2