The Canon Angle Finder C gives you a handy right-angle view with switchable 1.25x and 2.5x magnification, long eye relief, and a bright image that is not reversed left to right.
It comes with adapters to fit eyepieces of two sizes so that it will fit all Canon EOS SLRs, film and digital. In my experience it also fits numerous other SLRs with rectangular eyepieces, including the Nikon N70 and D70, Olympus OM series, Minolta SRT series, and many other classic SLRs.
If your camera also has a focusable eyepiece (as the Digital Rebel does), the procedure for focusing the Angle Finder may be confusing. Here`s how to get the 1.25x and 2.5x settings to be parfocal. First, take the Angle Finder off the camera and use it like a little telescope to look at objects around you. Focus it on something about 1 meter (40 inches) away. Then put it on the camera and focus the camera`s eyepiece so that you see the screen clearly.
At the telescope, what I do is alternate touching up the focus of the telescope and the Angle Finder, trying to make the stars as sharp as possible. That`s the only sure way. Prefocusing the Angle Finder on the focusing screen isn`t good enough, because your eyes will shift during a long observing session.
Is 2.5x magnification enough? Yes, it`s gracious plenty. Remember that this is not reckoned on the same scale as the 6x rating of Nikon`s DW-4 `stovepipe.` The Nikon is treated as a magnifier by itself.
On that scale, the eyepiece of a normal SLR is about 5 times the `viewfinder magnification` specified with a 50-mm lens. Accordingly, the Digital Rebel eyepiece is about 3.8x, and the Angle Finder multiplies that by 2.5, ending up with over 9x total magnification. Confused yet? If so, just remember that this handy gadget does its job.
Michael A. Covington is the author of Astrophotography for the Amateur and other books.