Pinhole shot in the Glen

Thought I'd try adapting a camera body cap to allow "pinhole camera" type shots. This involved making a hole in the cap and taping a piece of aluminium can to the inside, after making a very small hole in it. Put the Camera in Manual mode, stick it on a tripod and shoot.

Some "interesting" shots were produced. Went down Roslin Glen with M this afternoon and this was the best of the shots.

Strange "dots", like small concentric circles appeared all over these shots (sorted with PS) but they don't appear on normal shots with a lens. Not sure what these are.