remains of the day

A view from my bedroom window tonight - a lovely crescent moon and the orange of a setting sun on a rather beautiful autumn day. However...

I have broken my camera! I was trying another lens from my old Canon camera that does fit or so I thought. After taking these photos I went to change back to my normal lens and something fell out of my camera body. It is rectangular plastic piece (what it is exactly I am ignorant about) but now when I look through my lens there is a black circle around the view. The image is still fine though when I take it - just the view is distorted.

Oh dear me, oh dear me...