About three weeks ago I was shooting at the zoo, and on one particular shot I noticed a sort of shutter lag on my 50D. It wasn't a delay from pressing the shutter button until actuation of the shutter. Rather, the shutter seemed to hold open for much longer than the shutter speed was set in camera. I think I was around 1/250, but the shutter actuated as if I were at around 1/5 or so. It only happened once. No settings were changed before or after that particular occurance. Unfortunately I didn't make note if that particular shot was heavily over-exposed.
Then last weekend, the same thing happened twice in succession. I immediately reviewed the photos and they weren't over-exposed. The shutter responded as if it were taking a much longer exposure than than it was. Weird.
The only thing that's changed recently on my camera is the lens. I got a 70-200 f/4 IS in December. And it's only happened with that lens attached. But it's been so intermittent I don't know if that's the cause, nor if it even could be the cause.
If some responses are to send it in to Canon, I'm fine with that, and will do so if it worsens. Just wondering if anyone else has experienced this issue with the 50D.