I love my hasselblads, and I love shooting nice transparency film with them. I don't like polaroid backs so much though. Messy, slow, clunky, and an additional expense
I have not made the jump to a digital back yet, and I know I will in due time. But in the meantime, I am wondering if a digital proofing back exists.... Something low cost and low rez that can be used like a polaroid back, just to check lighting a composition quickly on the back itself, ideally including a histogram.
Just wondering if such a thing exists....
It doesn't really exist - I'll outline some options but you'll see that they don't really match your wishlist.
All the "cheap" options lack a built-in display and limit you to operating tethered to a PC or more commonly a Mac. You have either 35mm-crop, single-shot colour backs (like the H10); or full-frame, scanning backs (like the Betterlight), some of which I've seen in Hasselblad V mounts. All are older, used gear.
To become fully portable and get an image & histogram display on the back itself, you move up to less cropped digital backs which are at least double the price (2k+, even used) and which make images that are at least as good as scanned 6x6 transparency film. This kind of defeats the purpose of using them as mere proofing backs!
A separate, small, used APS DSLR with a matching-FOV (zoom) lens would be the cheapest and best option for "digital proofing". It covers metering, lighting, and composition...but not DOF, or bokeh rendering - only the Hasselblad's own lens can deliver those aspects.
BTW, the reason "it doesn't really exist" is that large-area film sensors like Polaroids are only marginally more expensive to produce than smaller ones, whereas large-area silicon sensors are exponentially more expensive to produce than smaller ones. Their resolution is not hugely significant in cost terms; it's all about the area in contiguous square mm. Kodak produces a large CCD with chunky, low-res 24 micron pixels, but it costs about as much as their similar-area high-res chips with ~10 times the megapixel count. Scanning backs offered a way around this - very long but very narrow CCD arrays. A battery-operated scanback with a built-in LCD display would have been the ideal Polaroid replacement (Polaroid developing time being replaced by scanning time), but AFAIK they don't exist - they are an idea I just came up with!