Canon 5D--Sharp at ISO 1600

I've had a Canon 5D for awhile now and while some of my pictures are excellent (like the one above taken at ISO 1600 without any noise); others are hazy.

When I was in the Amazon last year the mirrors fell out of place near the sensor. I put some fingerprints on them to slide them back in place and am wondering if that might be the cause of the haze.

At any rate, I love my 5D.

The camera has a full-frame sensor (35.8 x 23.9 mm CMOS), is 12.8 MP, has ISO 50-3200, 30-1/8000 shutter speeds and B mode (Bulb exposure mode, lets you keep the shutter open as long as you hold down the shutter release button)