The answer to my Guess Which Gear question is:
Mamiya RZ67 Professional Pro II and Mamiya RZ 110mm F/2.8, using Fujifilm FP-3000B (Poloraid-type) B&W film:
As the name implies, the Mamiya RZ67 is a 6 x 7 film format system. Its film “sensor” size can be appreciated by looking at this comparison:
This is a modular system and the Polaroid film back provides less “sensor” size (and less image quality) than 120 film, but I purchased it along with the 120 film back so that I could get instant results and feedback. As you can see from my first Test Image, I messed up on my initial settings (I had the ISO on the camera set to 800, while the Fuji FP-3000B is pegged at ISO 3000) so it was a good thing the damage was limited to only one image vs. an entire roll of 120 Kodak Tri-X.
[Incidentally, Fuji has recently announced that it is discontinuing this film 😦 . There’s an online petition asking Fuji to bring back the FP-3000B and so far there are over 10,000 signatures. You can still find it in stock, but prices have jumped quite a bit. If you’re interested in using it, buy it while you can — and sign the petition!]
Knowing my love of small Leica rangefinders, why did I even look at this behemoth of a camera? One word: PORTRAITURE.
If you look at the sample images online, you will be amazed. Hopefully, I will produce something worthy of this camera. The gear, for me, will be relegated to formal shooting, which means I will seldom use it. However, given how easily and inexpensively one can obtain such capable film-based medium format systems, the decision was easy.
As a side bonus of first using the Polaroid back on the Mamiya, my kids were amazed at seeing “the pictures come out of the camera, like in the old cartoons!“. It’s great to see that in this age of digital wizardry, something as old as this can fire up their imagination.
Now… off to dig up my old film developing equipment and brush up on…
My Method for Processing B&W film
Thanks for your interest.
—Peter.
Prosophos 
Great and interesting choice Peter! I’m not really into MF film formats and equipment, and my guess was not taking into account critical details like the 6×7… oops!
I’m looking forward too seeing more from your new ‘beast’, and learn from your experience.
M
Thank you Matteo.
What a good decision. Welcome, and enjoy, as I enjoy it to use analog and digital cameras. Because the result, the picture is important. And nothing else!
Thank you Alex.
I used the RZ with the polaroid back and 4×5 Fuji Provia preloaded transparency film. Beautiful 7×7 transparencies and the convenience of not having to use sheet film holders. The RZ was my go-to film camera back in the day, shooting mainly Fuji Provia 220. Using the RZ about 95% of the time, the revolving back and stellar image quality made it a beautiful solution for virtually any assignment. And Peter, you’re correct about the RZ being a great portrait camera.
Haha, well firstly I’m a bit miffed with myself for not seeing the previous post until this morning, thus missing my chance to have a guess. (I wouldn’t have been right anyway)…..
Really interesting and brave, it won’t surprise you to know I have this behemoth of a camera, I’ve only put test rolls through it to check functionality and it sits in line with quite a few others, awaiting attention. Nothing can prepare you for the weight of this thing but the results it can deliver are difficult to ignore.
I signed the Fuji petition some time ago, suggest others do also, it may help.
Excited to see what you come up with.
All the best, Jason.
Congrats Peter…..sounds like you are going to have a bit of fun with this “beast”! As I mentioned I’m eyeing off a Mamiya 7ii at the moment. In contrast to this camera it is very light for it’s size.