Wedding shots ... wide to normal
Then 17-50 f/2.8 range is very popular for the APS-C sensor cameras (α100, α200, α300, α350 & α700) for weddings.
For SONY, the TAMRON SP AF 17-50mm f/2.8 XR Di-II LD Aspherical (IF) lens comes to mind. It is lightweight (18 ounces) and relatively easy to get.
Speaking for a bargain, the 17-50mm f/2.8 performs quite well, overall and will only set you back ~$450.
Another consideration, which is definitely a notch above, is the SONY 24-70mm f/2.8 CZ lens
and its wider companion, the 16-35mm f/2.8 CZ lens.
The two lenses both allow for a wide-angle shot and also for some distance, with amazing clarity. They are quite a bit more to lug around, though, at 33 oz and 30oz, respectively. They both have a price to match. The pair of SONYs ... $1599 and $1899, respectively. :rolleyes:
All three lenses have the widest aperture (f/2.8) available in zoom lenses, across their entire focal range.
You also might consider an external flash (HVL-F58AM or HVL-F42AM) and diffuser, just in case things are a bit dark than even f/2.8 can handle, unless this is a daytime, outdoor wedding.
I am certain the other wedding photographers might have some further insight on this. :D
A wedding shoot? Get ahead of it
The SONY HVL-F42AM (<- click on link) is the probably all the flash you will need for an assignment like a wedding. The diffuser can be a number of things from a simple rubber band & placard to a modern-design flash fitting.
Personally, I am quite happy with the Gary Fong Whale Tail (<- click on link). It comes in a kit and you basically place it over your flash head and it uniformly diffuses the light in a way that reduces "flash burn" (the unsightly white 'hot spot' your subjects can get by using an undiffused flash) and "hard-shadow" (a black outline around you subject created by the angle of the flash to the subject). The diffuser can save you a lot of "touch-up" time on your closer images.
If you really are going to do the wedding, you need to practice with the flash and some dummy subjects, to understand the effects you are wanting to produce, eg "ceiling bounce" shots, table shots, group shots, etc. You need to purchase the flash right away and get start with that kind of thing and make notes on what work better than other positions. Also, a set of eight "AA" quickly rechargeable batteries (2400 mAh or better).
The TAMRON lens I mentioned earlier is going to be key and the most affordable of these type of lenses. Just swallow hard and get one, to get started practicing. You do not want to be "unpracticed" when the main event takes place. It is far too easy to mess things up when you do not know how to properly use or gauge your equipment.
Flash photography has a tendency to be hit or miss. The diffuser device will certainly help in that regard. The "Whale Tail" is designed to redirect flash angles, also, giving you powerful control of intensity and even color.
You will often find that lamp color (light temperature) is going to play a role in your shots and affect the White Balance of the camera. Fluorescent lamps look kind of green, Tungsten lights look rather yellow. Being able either match it or dominate these colors will be the role of the flash "gel" (a small colored insert that slip in and out of the diffuser. It comes with the Whale Tail kit and can be a true asset when things get questionable looking. Like I said ... practice ... see the entire image, not just the pretty lady in the middle.
Always take the BACKGROUND into consideration, because people see that too when they look at your work. Try and position yourself so there is nothing around the subject's head that looks like a "growing limb" or antennae. Stay away from mirrors anywhere behind or around the subject, as they can cause havoc with errant reflections splashing back on the subject or surroundings when the flash goes off. Best way to check is to set off a couple of casual practice shots to reveal this, but bear in mind, this can be annoying to your "subjects." People tend to have little tolerance for flash photography. Especially, a busy bride wanting to yuck it up with her well-paid for guests.
Checkout the setting, beforehand, if at all possible. Take a friend (or two) with you and use them as the "positional dummy" to check lighting conditions and locations. Remember the time of day, because filtered sunlight dramatically affects rooms through windows and such. If the wedding is a 9AM ... be there @ 9AM ... not 3PM. Even though you are using flash, the "story of light" is completely different. Obviously, you cannot plan the weather ... but, try to get in both cloudy day & sunny day practice shots. Being new at flash mean you need some "time behind the gun" ... so get some. :cool:
If you really want to be "anal" about it ... you stick around, not moving from your shooting spot and snap an additional couple of shots of each location with nobody in front of them. You then use these naked background shots for "cloning" corrections, later, when you post process. You would be amazed how those nasty shadows in the original just seem to "evaporate." ;)
Sorry for being long-winded, but you've got work to do.