I have been given a toikina 80-200 lens for My Canon AE-1. I am having problems focusing the lens at higher settings. The center focusing circles will go black and I can not focus. The Camera hacs no problems with two other cannon lenses.

Is this a problem with the lens or the camera conection? Am I doing something wrong in the focusing with a telephoto lens? Is there another waya that I am supposed to be focusing using this lens?

You advice is greatly appreaciated.

-- Mike Lewis (Elsel@aol.com), September 11, 1999

Answers

The viewfinder gets dark because the lens is probably a variable aperture zoom. I'll go out on a limb and guess that the maximum aperture at 200mm is f5.6. the viewfinder in older cameras like the AE-1 will start getting pretty dark at that aperture. Mount a 50mm f1.8 if you have one, set it to f5.6 and push the depth of field preview button, and you will see what I mean. I remember my AE-1 getting quite dark by f5.6, and a friend's Nikon was almost unfocusable by f4 indoors. On the AE-1, the focusing aids in the center will be effected first, and that is what you are noticing.

-- Brad (bhutcheson@iname.com), September 12, 1999.

Ditto what Brad wrote. Split image and microprism focusing aids tend to get pretty dim with slow lenses. Most zooms lose an f/stop toward the long end of the focal range. Try shifting your eye slightly while focusing, or use the plain portion of the focusing screen. You could try focusing at the low end of the zoom before changing to higher magnification, but that doesn't always work. Some zooms defocus slightly as you zoom around.

-- Lex Jenkins (lexjenkins@hotmail.com), September 21, 1999.