I'm writing up a longer article about my experiences of using a digital back on my Bronica system, but for now, I'll do an abbreviated version for this forum.
First of all, the disclaimer - I do not work for Kapture Group, Silvestri, Hasselblad or any of the companies that either manufactures or supplies any of the products mentioned in this post. I am just a Bronica user.
Although I use my setup a lot indoors on a tripod, I do walk around a fair bit with it and do street photography handheld. The whole lot, including 2 batteries, one lens and waistlevel viewfinder fits into a fairly small LowePro Nova 1 AW bag.
Anyway, superfluous introductions aside, when I started my survey to find out what solutions were available to my Bronica system I found 2 - the ones from Kapture Group and Silvestri. They both appears to be very similar, they both cost US$895, and they both take several weeks for delivery. Presumably, they machine it up when they get your order. I ordered mine through Shriro, from whom I also purchased my Ixpress back. I understand from the local Phase One dealer here that they will be happy to order the Bronica SQ or ETR adapter for you if you want to attach a Phase One back in Hassy V mount to a Bronica SQ or ETR series camera if you're buying a back from them.
Inside the box, is the adapter wrapped in bubble wrap and a plastic sleeve; the release pin on a string and the instruction sheet printed in colour. The fact that this pin is needed to attach or remove the adapter from the body means that in the field, it will not be a small matter to use one body with both MFDB and a film back since switching involves removing the MFDB, storing that safely, getting out the pin, removing the adapter, attaching the film back, remove the dark slide, etc., etc. Easier to get a 2nd body from KEH.com and dedicate one body to film use and the other to digital.
Upon removing the adapter from the packaging, you will wonder at how this must be the single most expensive sliver of metal that you have ever bought, but hope that it will be well worth the expense.
You will need the pin in order to attach the adapter to the camera body and to remove it from the camera body. With my unit, the adapter itself went very nicely onto the camera body, fitting exactly without any play or gap.
Here's a comparison between the Bronica 120 rollfilm back and an Ixpress V96C.
The adapter is intended to be used to mount only digital backs with a Hasselblad V mount and will not enable the use of Hasselblad V rollfilm backs like the A12 since there is no film advance gearing slot in the adapter.
For what I want, it works well. The Ixpress backs normally come fitted factory default with 250 microns of shims between the back itself and the mount. I found that infinity focus was maintained with the factory default shims and no focus shimming was required to achieve correct focus.
If you're wondering how the back fares with a prism viewfinder attached, here's what it looks like, but you might get nose smudge on the LCD...
Note that in this photo, the sync cord has not been attached. In actual use, you will need to use the flash sync cord to synchronise the back with the cameras shutter. You can also see the adapter plate clearly in this shot in between the camera body and the digital back. In the case of the Ixpress, it will only report ISO and White balance correctly in the EXIF header in the images. No aperture or shutter speed information is recorded and defaults always to f/90.5 @ 30 seconds.
The standard SQ focusing screen is all I need to focus and compose since it already comes scored for horizontal and vertical 6x4.5 compositions, it shows a central 42.5mm x 42.5mm square in the middle, which I used for composition for the square 36.9mm x 36.9mm sensor on the Ixpress without any difficulties at all, but I guess that's just me. I also never use the metering capabilities, and manage to estimate exposures very successfully.
Lenses:1. There are 2 types of lenses available for the SQ series - the older "S" series and the newer "PS" series. The quick answer is that the newer PS lenses are better of course, with better control of contrast, flare, colour, etc. In terms of sharpness, my "S" lenses are OK for my needs, but PS lenses are preferred.
2. Supposedly, there was a 35mm fisheye and a 40mm ultrawide available for the Bronica SQ system, but so far, I have never found them on the used market, which means that your wide angle options are practically non-existent. For all intents and purposes, the widest easily found lens is the 50mm PS. So if you're a wide angle junkie, you will find this restrictive.
Hope this helps.