Originally posted by Medium FormatPro Depends upon the caliper of a true professional photographer. Ideally most professionals doing a wedding would use medium format and then switch between something below an 80 and then something just above. I've also seen people use Leica's - especially the Leica Tri-focal length lens (but not zoom). For people using full frame dslr's... I've frequently seen people using two bodies - both with fixed lens.
The idea behind so many people electing to use the fixed lens is the better optics. If by chance it isn't quite close enough in the original that the mp of the sensor will still leave enough room to digitally zoom into the image later. Imagine also having a medium format between 50 and 80 mp - which still leaves quite an extraordinary amount of room to edit later and then enlarge to most any size - even when cropped extensively. Btw expect medium format backs to be available in the 105-110mp range within about six to eight months
On my behalf I must say used equipment is purely based on shooting conditions. Up in the northern Finland where I work most of the churches are old small wooden ones, ironically dark as the deepest pits of hell and that means no medium format since smaller sensors fare better in the dark. Last summer I was shooting in the second oldest church in Finland where even flash is prohibited since it affects the paintings. Leica, altough most propably having the best lenses in the world, is out of the question because you'll get the same results, when printed in reasonable sizes (the biggest we offer is 120x100cm), with SLR-system with a fraction of the price.
When I worked as a freelancer and used my own Pentax equipment (from K10 to K-5) I at first used my fast primes to cope with noise and when I rolled up the evolution of Pentax bodies I started to use my f/4 and F/2.8 zooms and eventually the old trusty primes were used only when f/2.8 just wasn't fast enough. As I started working in fairly large studio I had to use their equipment (Canon 1DsII to 5DmkIII) i grew quite fond of using two bodies and two fast zooms (16-35 and 70-200) during the wedding seremony and in the afterparty switched the 70-200 in to 50 and 85. Medium format, in my opinion, is reserved for the portrait work where you are not in the hurry and thus have the time to get the best out of that sensor.
During the film days a medium format body or two with changeable backs loaded with fast negative film was the ultimate answer since it actually worked better than the same film in 35mm format.
And for the actual topic
I can't wait having full frame K-mount body and fast ultra wide zoom lens since the only reason I'm not still using my own equipment instead of company offered Canon is the lack of that nice 11-16/2.8 all the others are getting in aps-c from Tokina. Also the PTT-L system could get a tad more consistent.
edit: Also, while being quite fond of the 16-35mm focal lenght, I'm not that fond of the image quality of said Canon lens wide open (even the II-version isn't that good).