Hi, brand new to the forums here.

I recently purchased my first MF, a Mamiya 645 Pro, and took a few rolls of portraits. I was very careful to use the split-screen, harkening back from my old Canon 35mm days. Most of the photos returned back-focused. Although I was mostly wide open, it was consistently behind my intended focal point.

I shot a quick test roll yesterday, tripod mounted and it seems that indeed the prism back focuses. I've read this could be mirror alignment, a curved focusing screen, or misalignment/installation of the focusing screen.

Can anyone recommend a Los Angeles area camera repair shop that can address this?

OR, is there another route I should take first?