You said you want to get 465 back for mamiya so you can shoot 16 pics, why not get a 220back, replace it with your 120 that takes 10 shots, and then you can do 20 shots. (With the 220 back of course)
For those long exposures, your technique seems awesome, but it is way safer to get a cable release. You'd be a fool not to have one with long exposures, or even regular exposures. It's just safer that way.
For those long exposures, your technique seems awesome, but it is way safer to get a cable release. You'd be a fool not to have one with long exposures, or even regular exposures. It's just safer that way.