I have to following problem: I recently bought a Pentax 67 and an RZ67 and can't for the life of me make properly levelled pictures with either. Using a bubble level in the cold shoe of the Pentax's wooden grip doesn't seem give me proper levelling, and the same goes for the hot shoe on the side of the RZ.
I bought a three-way tripod head with bubble levels on it, but it doesn't seem to be accurate either (and trust me, I tested it PROPERLY).
So what's your solution for levelling these classic cameras? And please don't tell me you're fixing the levelling problems in post, because my goal is do it properly "in camera". :)