I am wondering what the practical difference between AF and AFD lenses is. I am considering a 35-70 f2.8 lens and wondering if the D option is something I (would need) should pay for. Also, I've heard that the AFD version might have some better coatings.
Dimiter, AF-D lenses calculates the distance from the camera to the subject. This feature is useful where distance is a factor in calculating proper exposure, e.g. flash photography. If you don't do a lot of this type of photography, you can get by with a non-D version of any lens.
Mon 10-Dec-12 05:42 AM | edited Mon 10-Dec-12 05:42 AM by robsb
That is not quite correct. The new cameras use the distance data in 3D MAtrix Metering to help determine the overall exposure even when not using flash, so it is better to get the D version of the 35-70 and that will also guarantee a much newer lens in the series before they stopped making them.
Sun 09-Dec-12 09:15 PM | edited Sun 09-Dec-12 09:17 PM by MEMcD
The D type and G type lenses provide 3D Matrix metering and 3D Multi Sensor Balanced Fill flash. The pre-D type lenses use Color Matrix metering. As stated above, the distance informations increases the exposure accuracy when using flash. I have both the AF 35-70mm f/2.8 and the AF 35-70mm f/2.8D and in practice, 99.9% of the time the difference in exposure negligible between the two. Good Luck and Enjoy your Nikons!
When using a hot-shoe mounted flash and firing it forward, there is a negligible effect on the flash exposure. But as soon as you raise up the flash head or swivel it to do bounce flash, the D feature is not used by the flash exposure circuitry anymore. It's also true that the D models will be newer than the non-D models.