Lens Cap Shutter

A lens cap makes a perfectly good shutter for slow speeds (1/2s or longer).  With slow media, like photographic paper or wet plates, this works a treat.  With slow film (say ISO100, pulled to ISO50) you can do it by shooting at small apertures.  Or just work in low light…  

Be careful not to wobble the camera while you remove the lens cap.  Turn it gently to ease it off, drop it down below the lens, move it round the side and up above the lens, counting however many seconds your exposure is, and pop it back on.  Always practise first before you remove the dark slide and make the exposure for real.