Have been very happy with the AFI II 7 back on a Hy6 - it works well, connects practically flawlessly to the camera, and has great user interface. The electronic interface to the camera has been pretty much seamless, with the occasional glitch taken care of by a restart. Usually any problems are from low battery levels, easily fixed with a fresh battery. I've rarely tethered, and had problems with it, but I think these are due more to a bad hub and cables than the back. Again, I rarely tether, and honestly haven't spent enough time to figure out what isn't working. But it has worked in shorter bursts (says up to an hour) without flaws.
Things to like about the system: the AFI (or Hy6) has a lot of flexibility, and can be profiled in any one of a different ways. For lightweight use, a single lens, WLF, and film back work well. Also the digital back can be used as a heavyish walk around - had good luck with a monopod, shooting down to 1/40 without difficulties (60mm lens) and even as low as 1/20th with mirror lock up, and a burst of three shots, one will usually come out. That makes it able to shoot into shadows fairly well, still around ISO 100. Or it can be set up with prism, larger lenses, and on a tripod for more serious work. Easily configurable.
Focus offset allows tuning for each lens, which is quite effective, and the mod.2 will save these but only for AF lenses. its easy enough to keep a list of the offsets on your phone. Easy to change, and well worthwhile. A 150 telexenar, thought to be soft, dialed in sharp and is a favorite lens.
Lenses - The lens range is quite extensive, but you need to be clear on AF vs MF lenses. I prefer the MF lenses, for flexibility, and cost benefits. The focus confirmation is dead on, so its pretty easy to use the MF lenses. One AF lens (say the 80) with the 1.4 TX gives some pretty good traveling flexibility too. And its fast. I've been less interested in the 50 AF or the 180AF due to size and mass, but they are good lenses. In general, all the Schneider lenses are excellent, and compare well to the current tech lens, the only exception being the 40mm which is a bit soft on the edges. All others are strong edge to edge, the distortion (if any) is simple barrel, not the more complex mustache of the Zeiss. I have little familiarity with the Zeiss lenses, which are a generation behind the Schneiders, but more likely comparable to the Hassy versions, loved by many.
Some of these lenses are really very good, tack sharp, consistent color and look - the 300mm is a "gotcha" lens, hard to use, but wonderfully sharp when you get it all together. The 90 is a standout and gives nothing up in comparison to a Rodie 90 HRW. Favorite is the 60mm Curtagon. All pretty much available from Eric Hiss (Rolleiflex USA), typically used.
The only shortcomings (IMHO) are the lack of good shifting options and the weight/mass. Shifting is via the 55mm PCS boat anchor, pretty good at f11 or 16, but not small by any means. The eight of the system is not ideal for traveling with many lenses, but pack a second lens, and some batteries, and its OK. A bit awkward in the shape, but very easy to use. The mod 2 has some upgrades, but isn't critical. The first version works just fine for me.
The ergonomics of the camera are well considered. The controls are easy, the level of electronic integration and flexibility was ahead of its time, but is by now standard. There are a myriad of options, most of which we never use - such as focus trap, bracketing options, and shutter delay (so there is no need to carry a cable release) a bunch of others, so the camera can really do what you want. I tend to use it pretty basically, and like it for that. The MLU is right at hand, so its easy to set for the shot, and then lock up the mirror quickly and shoot. At low speeds, the leaf shutters just have no vibration. On a borrowed Manfrotto monopod (with three little legs), the leaf shut and delayed shutter allowed 8'" exposures!
The Leaf digital back - it does pretty much all you would ask. The rotating sensor is quite nice, no flaws - just don't rotate it while the back is processing. I prefer the 33mp back due to its faster processing, longer battery life, but might upgrade to a Credo 60 if one is available (as the last, most recent upgrade path for the AFI mount). Use C1 for processing. Sometimes I've picked up a bit of a color tinge on one edge of the back, probably due to overheating, but its rare, and only happens at a time. No centerfold issues, bad pixels etc. The back mounts well, but is fussier on third party mounts for tech cameras. Had to change the prongs from the longer pointy ones to shorter stubby ones (provided by Leaf to fit in tech camera mounts) but easily done at home with a socket wrench and strong nerves.
Hope this answers your questions. If you have more, let me know, or talk with Eric. He's quite knowledgeable and very helpful.
Geoff
PS - many of these were AFI shots, although some with film...
http://www.gigi-photos.com/f503220439
