1.Custom Setting 23 : Sharpness

The D-1 incorporates a high-speed image processor which designed to offer immediate, high quality results in a variety of photographic conditions.

Custom setting 23 allows the control of image sharpness, so that the camera can be set to produce a sharp, vibrant image ready for instant use, or a smoothly contoured, sophisticated image which will withstand a high degree of enlargement. For a quick summary of custom settings see the FAQ section.

The Sharpness setting explained.

The sharpness setting regulates the amount of  "unsharp mask" that the camera adds to the image. Unsharp masking is a technique where the boundary between different areas of tone are enhanced by lightening a line of pixels on the brighter side and darkening a line of pixels on the darker side. At extreme settings, such as are possible in Nikon Capture and Photoshop, it can look as if the image has been outlined with black and white pens to create a line-art impression which is superimposed on the original. The controls associated with computer sharpening are intensity (how pronounced the effect is), halo (the width of the sharpening lines) and threshold (at what level of tone difference the effect commences). The D-1 custom setting simply allows the intensity to be modified.

One of the most important factors when considering sharpening is that the visual effect depends on the size and resolution at which the image is finally displayed. For example if an image is heavily sharpened and then enlarged, the effect will be less pleasing that if the image were enlarged first and then sharpened afterwards..

Also to be considered is the fact that sharpening increases the visibility of any noise (equivalent to film grain) in the image.

The D-1 allows four choices of sharpening, based on the fact that at a resolution of 2000 x 1312 pixels, normal (default) sharpening will be suitable for a print size of up to about A3 under normal conditions. 

High sharpening mode should be reserved for situations where the image size is kept to about A4 or less, and an immediate, punchy effect is required, for example if the subject is of too low contrast or is flat.

If it is intended that the image is to be printed at a larger size (or cropped and enlarged) then the setting of low may be more suitable.

For portrait work, or situations where smoothness of tone is paramount, the sharpness may be turned of by setting to none. (Note that by shooting in raw mode (CSM28:1), the camera sharpening is disabled and the effect can be added afterwards in Nikon Capture.)

Practical examples

The image below shows four samples each of which were originally 100 pixels square, taken with a D-1 camera. The images have been made monochrome for the purposes of this explanation.

Each image was taken with a different choice of sharpness setting. The centre inset shows a thumbnail of one of the images at its original format, before cropping. Note that each quarter square is 1/50th of the original image width (2000 pixels).

The setting "none" produces a smoothly graded image with very little noise. As the sharpening is increased, more grain becomes visible as the image edges are enhanced. The visual effect of the sharpness setting  is very dependant on the actual subject matter and viewing/printing magnification. These image samples have been chosen to show how sharpening increases noise/grain effects, rather than to show the actual desired effect of sharpening the image.

Conclusion

Sharpening is a visual effect which adds clarity and immediacy to an image.

The D-1 camera provides a number of setting options to allow the photographer to choose whether to sharpen the image in-camera for immediate results, or to sharpen later for more control.

Tutorial: Sharpening and filtering with Photoshop.

Example 1.

With the camera sharpening set to none, the picture below (about 1/12th of the original image area) is smoothly graded with almost no visible noise. The centre circle has been sharpened by the Photoshop unsharp mask with an intensity of 200% and a halo (radius) of 2 pixels. The skin, eye and hair detail become enhanced as a result.

The smaller circle then shows the effect of the Photoshop median filter, which reduces the specular (point) noise: in this case it is not needed (see example below). 

The untouched crop is shown bottom right, inset.

Example 2.

The original image was taken in lower light than above and is slightly out of focus, with a very short depth-of-field. The camera sharpening was (fortunately) set to "high" which has allowed some of the detail to be recovered. To futher enhance image, the Photoshop unsharp mask filter has been applied to the area in the large circle ( intensity 200%, halo/radius 2 pixels, threshold 0) and the resulting increased specular grain/noise can be clearly seen. The smaller circle has been subjected to a Photoshop median filter, which has reduced the grain, but has made the image slightly softer as a result.

Note that the original image would have been four times the width of this crop. A combination of in-camera sharpening and Photoshop filter tools have helped to make a useable image from an original which was slightly soft.

All images were shot straight to JPEG at Fine mode (1:4) resulting in a compressed file size of about 1Mbyte. The original image before cropping was 7.5 MB.

Footnote

This information is intended to explain some of the ways that the D-1 can be used to achieve excellent results in a variety of conditions. Ultimately, it is the end-user who must choose which settings give the best results in each situation. There are no strict rules in Photography, being as it is a combination of art and science, inspiration and sheer hard work. It is Nikon's aim to provide equipment which can help the photographer to achieve his or her own ambition whatever the subject and conditions.