Given my critical observations about the a900 lately in wedding situations, I did want to share a few photographs from not-so-good wedding conditions... and to say that it is still a great camera. Even in lowlight.
Add action + lowlight... not so good... but that's an AF issue, not a sensor issue. So here are some recent snaps at moderately higher ISO settings in absolutely horrid lighting conditions. I mostly wanted to also share some workarounds in lowlight when using a speedlight (here, the 58)
Know that in most of these, the camera was set on manual at close-to-minimum hand-holdable shutter speed. If I were to shoot ambient only, the room was dark enough that I'd be somewhere around iso 3200, 1/40th. As it was, I set the camera mostly at 1/80th for the 135 and 1/50th for the 50mm... at iso 800. Then I set the flash on ttl, and pointed it at whatever surface was opposite of the face I wanted to light... If someone was in front of me and looking camera-right, then I'd point my flash slightly upward and over my right shoulder...in essence creating a big softbox from a wall opposite their face.
I rode the flash compensation some (i set the custom button on the camera body to access flash ec) but generally +1/3 worked well.
Wedding cake under blue spotlights... but with red spotlights in the distance. By bouncing flash to upper-camera-left, I was able to overpower the colored lights a bit to bring out the detail and even out color.
Father of bride, under deep red-gelled spots... flash bounced over my right shoulder to fill the shadow side of his face:
Flash bounced over my left shoulder... note how, by shooting with wide apertures and a somewhat underexposed ambient, you get great subject separation, a colorful and blurred bg, and soft main light from the bounced flash. You just have to make sure you have a wide enough aperture to get sufficient DoF, or you have to make very sure that the subjects' faces are in the same plane opposite the lens.
Not a flash shot... but a situation where the flash didn't fire (big room, needed much flash power in every shot). Was underexposed by more than two stops and was still recoverable... probably the equivalent of iso3200-5000. Not big print material, but at 5x7 and smaller would be fine.
Flash Bounced camera right, slightly over my shoulder... red-gelled spots providing light from camera left
So... the a900/58 flash are a nice partnership. Exposures are nice and even as long as you don't hammer it. Unfortunately the 58 is not a very robust flash and has overheated on me at every wedding. But... that's another post.