Most Canon , Nikon and various digi cams could be controlled in Image capture with some elbow grease.

Now in Leopard, when you connect to your Mac and launch Image Capture, select the "Download Some" button.

Here you can view thumbnails and notice in the tool bar - a Camera icon!

Click it and your camera takes a shot!
Good for table top photography and Macro work where you don't have to touch the camera and accidentally shake it - even on a tripod.

After you shoot, the image is available on your Mac as a thumbnail.

In addition if you open Bridge and point it to the folder the images are being saved to, you get a high quality preview too.

This has been available in Tiger as well, but I don't recall which dot-release it showed up in. With the Canon Powershot S410, at least, you have to have the camera in View mode. Hitting the Image Capture Take Picture button powers up the lens mechanism, the AF beam lights up, a flash picture is snapped. and the lens retracts back into the body. No LCD preview screen visible. Perhaps if you set exposure, color temp,etc in manual mode it may use those values but the lens defaults to wide open.

Strange, we didn't see it in Image capture here at work when connecting an S30 or S50.