D1H and D1X
The D1 was replaced by the D1H and D1X on February 5, 2001. The D1X offered higher resolution with a 3,008 × 1,960 - 5.3 effective megapixels sensor, and continuous shooting of 3 frames per second for up to 21 consecutive shots. The D1H was oriented towards fast action photography, keeping the same 2.7 megapixels image sensor as the D1, but pushing the frame rate to 5 frame/s for up to 40 consecutive shots. Both the D1H and D1X use the sRGB/AdobeRGB color spaces, which is an improvement over the original D1.
Read more about this topic: Nikon D1