I have a set of CTR-301Ps that I use for flash triggering digital and film gear (including Mamiya and Bronica). I bought a set of the RF-603N to use as a wireless shutter release but wanted to try to play with it on film when realzing I can't. I havn't tried modding it, but probably won't because the CTR-301P supports up to 1/500s sync so I can sync it with the leaf lenses of the Mamiya, Bronica, and other RF cameras.