Autofocus doesn't work when you're taking an astronomical image; you must focus the camera yourself. There are so many techniques for focusing a DSLR that I've devoted a whole chapter to it (Chapter 8, p. 89).

Obviously, you can focus a DSLR by looking into the eyepiece, just like a film SLR. Make sure the eyepiece diopter is adjusted so that you see the focusing screen clearly; your eyes may require a different setting at night than in the noonday sun.

But you can usually do better by confirming the focus electronically. The easiest way to do this is to take a short test exposure (such as 5 seconds for a star field) and view it enlarged on the camera's LCD screen. Repeat this procedure until the focus is as good as you can get it. If your camera offers magnified live focusing, that's even better.

Digital Camera and Digital Photography

Digital Camera and Digital Photography

Compared to film cameras, digital cameras are easy to use, fun and extremely versatile. Every day there’s more features being designed. Whether you have the cheapest model or a high end model, digital cameras can do an endless number of things. Let’s look at how to get the most out of your digital camera.

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