Notable features of the D40 include the same Nikon processing engine as in the D80/D200, in-camera retouching, help suggestions in the viewfinder, SDHC support, and an unlimited 2.5FPS continuous shooting mode. Note: SDHC (Secure Digital High Capacity) is a secure digital card format that allows for capacities beyond 2GB. ISO sensitivity ranges from 200-1600 and can reach an equivalent of ISO3200 with the HI 1 functionality.
One of the main differences with this D40 SLR and the other high-end models is that the camera does not contain an external focus pin. What this means is that only certain lens, namely AF-S and AF-I lenses, will be able to focus on the D40. Normal lenses will only be able to use the computer focus, not adjust the optical lens focus itself.