I was taking photos with my 300D the other day (had a Sigma 17-35mm f/2.8 attached). In the middle of focusing, the view finder became dark, or very tinted, but then went away. It happened 2 times, but I could hear a small click when it would go away. Could this have something to do with my shutter (maybe coming down half way causing the somewhat dark view finder?). Anybody else have this problem before? Thanks.
It's been working fine since, and this was 4 days ago.