Overall Image Quality / Specifics

Overall the D70 performs well, images sharper than the D100 (thanks to a slightly weaker anti alias filter and improved image processing) good tonal balance and a neutral color balance. Noise levels are low and the camera is usable throughout its full range of ISO's, a bonus is that the D70's noise appears to be more monochromatic with less noticeable 'color noise'. We had no major issues with image quality apart perhaps from the occasional brush with moiré / maze artifacts (Bayer interpolation issues, see below). Overall however I liked the look of the D70's images and am impressed with the improvements Nikon has made, Kudos. Thanks to the wider range of selectable image parameters you can get the picture look you like straight out of the camera, in several instances I found the punchy 'Vivid' mode produced some very nice results.

Impressive resolution, improved sharpness

I was impressed with the improvement in resolution and sharpness I saw from the D100 to the D70. Apparently quite a bit of this is down to a now weaker anti alias filter on the CCD which 'blurs' the image at a higher frequency than before. The side-effect of this is increased moiré, which you can read about below. Sometimes it's all very well to look at a resolution chart but difficult to demonstrate what this could represent in real life. Thankfully the two images and set of crops below more than confirm the improvement and demonstrate what the D70 is really capable of, some pretty impressive resolution.

AF-S DX 18-70 mm F3.5-F4.5G @ 51 mm
ISO 200, 1/320 sec, F10
AF-S 28-70 mm F2.8 ED @ 52 mm
ISO 200, 1/400 sec, F10

Moiré / Bayer interpolation 'maze' artifacts

So resolution is improved however this has lead to visible moiré / maze artifacts near the limit of resolution. Shooting RAW and processing the images on a computer later produced better results, obviously the D70's in-camera Bayer interpolation algorithms aren't capable of removing enough of this artifact for it to not remain visible in JPEG images.

Green to Magenta cast at high shutter speed

There have been several discussions on our Nikon D70 forum about an uneven color cast seen on images taken with a very high shutter speed. We tested for this problem with our review camera, we took a sequence of shots from 1/8000 sec downwards in one stop steps. Without any saturation adjustment there isn't any visible color cast, boosting saturation by +95 (a very strong boost which you would never normally use) did reveal some coloration at the sides of the frame. I personally don't see this as a major problem, it's very unlikely that such a mild effect in such specific circumstances would ever be visible in a normal shot.

No saturation adjustment Saturation boosted +95
1/8000 sec
1/4000 sec
1/2000 sec
1/1000 sec

Adobe RGB tagging bug

In the course of reviewing the D70 I identified a bug which affects the way images are tagged with color space. If you create a custom 'Optimize Image' parameter set which uses Color Mode II (Adobe RGB) and then revert back to one of the preset sets (such as Normal or Vivid) the camera continues to tag images with the Adobe RGB color space tag. This causes tag aware applications such as Adobe Photoshop CS to open the image with the wrong color profile assigned, essentially viewing an sRGB image in the Adobe RGB color space. Colors are displayed incorrectly and if you were to then print or output to the web the results would be quite bad. As you can see below Nikon View recognizes that the 'Normal' Optimize Image setting is selected and thus the image must be in the sRGB color space, however Adobe Photoshop CS only looks for the color space tag which it sees as Adobe RGB (1998). We look forward to Nikon fixing this problem with a firmware update.

Nikon View 6.2.1: 'Color Mode: Ia (sRGB)'
Adobe Photoshop CS: 'Color Profile: Adobe RGB (1998)'