Instead of constantly buying new lens caps on eBay after foolishly losing them (much like, err, me), you could just try the LensCapTrap, which attaches lens caps to the camera strap with a bit of belcro. It only costs $US6, but as PetaPixel points out, you could easily make this yourself. Or just stop losing those goddamn caps. [LensCapTrap via Petapixel]