short of having the couple come into the shade outdoors, it will be very difficult to gain the sufficient light to get the shot. couple of things to take note of:
- its a slightly heavier camera, different ergonomics, you'll need a slightly faster shutter speed to get gainfully sharp images with hand holding. so bear this in mind. the fastest lens on the hasselblad H system is the 100/2.2, which is my standard lens for medium format digital wedding photography. i shoot with the H4D-50 @ ISO 50 whenever possible, boosting to 200 or 400 where necessary. Previously I owned the H4D-31, which could do up to 1600 ISO. I speak from some experience.
- you can boost the iso to 800 or 1600, but compared to 35mm digital of today. its very noisy. these systems were engineered to work ideally at base iso, in place where you can feed sufficient light into the sensor. For me at least on the 50, the ISO is only "true" up to 200, anything beyond that - 400/800, is merely a signal boost within the parameters of the digital back. For black and white, its acceptable - gives the grain like feel of film. For color, while skin tones are spot on, 35mm digital may be better.
- autofocus is slow. its very accurate when it has enough time to nail the moment, though i have to say that as a person shooting with the 100/2.2, the "true focus" feature is exceptionally helpful for getting faces sharp at maximum aperture. sometimes you can't realize the full image quality outcome of medium format if your focus is off. especially with couples, shooting with a faster aperture to compensate for slower ISO and higher shutter speed naturally means the depth of field is much more shallow.
i will not recommend it. Personally, I sold my Nikon D800E in favor of the D4 when it came to wedding work - at least for Singapore, where most weddings are indoors, the benefits of a strong sensor with high color fidelity at high ISO cannot be under estimated. Shot a D3S prior to this and owned a D3X as well. The D3X could barely make it as a wedding camera at 1600/Hi-1 or Hi-2. Medium format restricts you further and the lenses are slower too.
the only place I could use a digital medium format hand held was when the couple were under spotlights - especially in the more modern churches that have all the glitz and glam. There I get roughly 1/90s, f/2.2 at ISO 200. Of course, skin tones are great, highlight retention is amazing, shadow density is stunning and that 16 bit color and image dimensionality means that most folks can immediately pick out a particular "difference" in the picture over 35mm film. I get mistaken far too often as a videographer, because most folks haven't had much exposure to the looks of a Hasselblad system.