I am only new to SLR photography and have just bought a Sony A700. I have just started playing around with my camera and have noticed an issue with focusing. I am not sure if it is expected behaviour or not, or if it can be turned off somehow.

The camera seems to be constantly trying to focus without me pressing the shutter button half way down. I find it annoying and would like to turn it off. I have a 100mm macro lens and trying to get a macro shot with the camera constantly focusing is quite hard. Even when I am walking around not even trying to take a photo the camera is always trying to focus and the noise gets a bit annoying

I have used a Nikon SLR before and it only seems to auto focus when the shutter button is half pressed. I am not sure if this is just a Sony feature. I know I can set the camera to manual but I would like to obviously make use of the auto focus.

Is anyone able to suggest if there is an menu option I can turn on so that the camera will only auto focus when I half press the shutter.

Any suggestions would be greatly appreciated.

Apart from this issue I am really enjoying the camera and have been really pleased with the image quality