I thought to give a preliminary report of my first full wedding shoot using the A900 alone ... I left my "Nanny Blanket" Nikon D3/D700 behind this time to really put the A900s to the acid test on it's own.
I apologize for the the long post ... it's meant for those perhaps considering the A900 for similar work.
Real World Criteria: obviously, this is just an opinion, but I think weddings are the hardest test of a camera's over-all performance of anything. Sports is also really hard, but it is a bit more consistent type of shooting ... where weddings have you shooting in bright noon sunlight one second and in a candle lit cave the next ... color temps range all over the place ... and everything is controlled chaos for 8 hours with almost no break in the action. You are shooting portraits/groups, decisive moment candids, wedding details, food shots, and a boatload of "must haves" that you get one shot to capture or you are toast. I could go on and on ... but trust me is ain't easy and your tools have to perform IF you want consistent results while delivering any decent level of decisive moment work that transcends snapshots and defines a specific style and approach clients will recognize and pay a premium for.
Now the Nikons are stellar at this work. Can't say enough about the speed and accuracy of the D3/D700 ... and some to the new lenses are quite good.
But I have to admit to being a lens snob ... and truly believe that there is something different to the Zeiss look. I also hold that opinion of the Leica optics. We can argue the merits of this opinion until Hell serves Ice Cream, but it will not change my mind. That the Sony offers a perfect range of Zeiss AF lenses (AF !!!!!) for wedding work IS the only reason I moved from Leica R into Sony tools.
The Arsenal: A900, A900 with battery grip (both with hand straps); Zeiss 16-35/2.8, 24-70/2.8, 85/1.4, 135/1.8; Sony flash and multiple types of diffusers, 100 gig of CFs, 8 spare AA rechargeable; 3 extra Sony batteries ... all snug in Think Tank Urban Disguise 40 shoulder bag. (I usually use a roller, but this wedding had us moving all over the place where I needed a compact, take with "working bag."
Observations/Performance: Moving at the speed of light for up to 8 hours reveals strengths and weaknesses in short order ... both of the system and the user. The question for me was ... will the A900 stand up to all the challenges that the Nikons handle so well? Lenses snobbery is one thing, but if you miss the shot, the lens doesn't matter at all. And, do I have enough experience with this camera to trust a wedding job to it (well, I wouldn't have even tried if I thought I didn't ... but there are unknowns until you actually do it rather than practice it.)
The A900 cuts the mustard, and delivers Zeiss deliciousness!
FOCUS: Happy to report that of 500 shots only a doz. or so were OOF ... I had zeroed in the focus calibration on both cameras and neither missed a beat even in really low light at the reception ... except when I accidently depressed the Manual Focus button located on the Zeiss lenses because of the way I hold the lens in my left hand and where my thumb falls. This is a nice manual feature until stuff like that happens ... then it's not nice. I rather that button not be there, and relegate it to a camera button for the right thumb to activate or something like that. Of have a AF lock for the lens button.
ISO: now the Sony can't hold a candle to the Nikons in this department ... but it did better than expected. I did a lot of shots at 800 with plenty of room ... as long as the room was slight over-exposure rather than heavy under. BUT, under wasn't as bad as I thought ... some noise but the kind I can live with. The criteria I use for judging this is in print form ... NOT on screen. I do not do much ISO 2000 even with the Nikons because I don't need to be fixing Raccoon eyes from dead overhead lighting at most of these venues. My preference is fill that is had to detect when possible ... and most of the time ISO 800 does the trick.
Flash: I did have some difficulty with inconsistent flash/ambient balance ... but I do attribute that more to me than the camera ... it takes awhile to grasp what to do with each different camera ... I had to relearn this when swapping from Canon to Nikon ... and now again with Sony. We'll see as time goes on. I'm not crazy with having to use the menu to alter flash comp., but there is a silver lining to that also ... I leave the screen on that menu and hit the function button to alter the flash comp .... the good part is that it is easy to see in dark conditions which is almost all the time.
What made it all worthwhile was opening the shots in LR ... the 3D pop of the images depicts a clear departure from my Nikon stuff (except maybe the Nikon 200/2VR which in itself is the reason to have a Nikon in the tool kit.) While there are other RAW developers that may be better, LR-2 is super fast for this type of work while being super secure at the same time.
I have a lot to learn yet with this camera, but it is looking more and more like the weapon of choice for my wedding jobs.
Pics to come once I process them.