The EOS 40D's Live View facilities are invaluable to specialist photographers, especially those involved in macro or astro-photography. Both require precision focusing, and the 40D's magnified focus assist mode allows you to carefully confirm the image will be pin-sharp at the focal plane.

In this video demonstration we've mounted an EOS 40D at the prime focus of a Televue Genesis SDF telescope, thereby effectively using it as a long telephoto lens. The telescope has a focal length of 540mm, which with the 40D's field reduction factor is effectively working at 864mm. Since this is still modest for shooting subjects like the Moon, we've also fitted a 2x teleconverter to deliver a final effective focal length of 1728mm. In the video you'll see how the magnified Live View mode can greatly aid focusing, whether you're photographing the Moon, the Planets or even stars. See below the video window for actual examples of the images photographed during this sequence.

As always, there's no need to download any new software - just press the play button in the middle of the screen below and wait for the video to start; you may need to press the button twice. The quality and any delay before playing may vary depending on your internet connection. And don't forget to check out our main Canon EOS 40D video tour which demonstrates the highlights of this DSLR.

Below left is the image of the moon taken during this video using the EOS 40D and the telescope working at an effective focal length of 1728mm; the image is shown here un-cropped, which illustrates the kind of focal length you need to even fill half the frame with the Moon. Alongside this photo are two crops taken from the original image, reproduced here at 100%. These represent zooming-in on the images using your computer until the pixels are viewed at 1:1. As you can see, Live View has allowed us to achieve a sharp focus on the Moon's surface.