Autofocus doesn t work very well when it s dark. What can I do?
Low-light autofocus is quite a challenge for any camera that uses a passive autofocus system, like all EOS cameras. Passive autofocus means that the camera simply looks through the lens and reads whatever s there – it doesn t send out infrared or sound or light or radar beams or whatever to determine the correct focus distance. (the AF assist systems used by most Canon cameras and flash units don t change this, since the lights are optional assist systems and are not required by the autofocus system) Generally speaking the more expensive the camera the better the autofocus. There are exceptions to this, but it s a reasonably accurate predictor of how good AF is going to be when light levels are lower. So a top of the line EOS 1V is going to have wildly better low-light autofocus than an old EOS 1000 consumer camera, for example. This doesn t quite apply with digital cameras, though – the D30 and D60 are both more expensive than roughly comparable film cameras, but have very poor low-li
