hi, i've admired pinhole photography for years, but have never bothered trying it. i have been considering getting one of the finney pinhole body caps to use on my voigtlander r3a, but haven't heard much about the product. does anyone here have experience with the finney pinhole caps, and if so, what is your opinion of them? do they work well, or would i be better off buying (or building) a dedicated pinhole camera? thanks.