Its been a workhorse for me with no issues whatsoever but now it won't work at all. The viewfinder is dark and the autofocus moves but doesn't lock. Has anyone else had this issue? Not getting any kind of error message.
Something unusual is happening, for sure. Aside from a general lack of light, I can think of four things that make the finder dark: (i) the lens is stopped down to a very small aperture; (ii) the mirror is up (or fell off); (iii) for 1D-series bodies, the finder shutter is closed; and, (iv) the lens cap is on. Does it do this on more than one camera? If the aperture is stopped way down, you should be able to see it by looking into the front element while it's on the camera.
Yes on two different cameras. It looks like the aperture may be stopped down and locked up as changing the aperture does nothing. Is there a way to release it?
Doug C. wrote:
Yes on two different cameras. It looks like the aperture may be stopped down and locked up as changing the aperture does nothing. Is there a way to release it?
So, when the lens is off camera, hold it up to a light and look through; if it's still dark, then the diaphragm is stuck closed, or nearly closed. If this is the case, put it on a camera, set the aperture using the camera mail control dial (in Av)to f/8 or so, and then 'exercise' the lens by pressing and releasing the DOF preview button.
OTOH, a remote possibility is that there is something shorting out (i.e. connecting) one or more of the lens-to-camera contacts at the base of the lens. Who knows? Maybe a short between pins 2 & 3 makes the aperture go to max stop-down position. Anyway, it's probably worth a look.
Aperture blades are controlled electronically via lens mount. Are the contacts clean (try using a pencil eraser). Does the camera do that with any other lens?
Does the lens stay stopped down when you take it off the camera?
