Hi!!
I'm shooting large family portraits outdoors tomorrow for 25th anniversary.
I have a Canon Rebel Xsi with Kit Lens. I've photographed groups before and they come out great and full of spirit but the crispness of the people in the group is never what I want it to be.
Any advice on what settings may help??
"ON"
OK, sorry, I couldn't resist that, I've had a bad week :-(.
previous posters are correct. Your kit lens may seem a little fuzzy because it's not being used at its optimum aperture, which is around f/8. Hopefully your kit lens is the stabilized version, as its optical quality is far superior to the older version (as well as the obvious advantage of IS). IS or no IS, keep your shutter speed above 1/100s (or at least 1/60s) to avoid blur from people moving. If you don't have enough light for f/8 and 1/100s or faster feel free to bump your ISO up as high as 400; if you're exposing properly you'll likely not notice the difference in the final image unless you're making really huge prints. If you're outdoors, not in the shade, and it's not getting dark, you should be fine at ISO100 though (
read this if you really want to know).
Your camera & lens are light enough that you should be able to get away with using a fairly inexpensive tripod. make sure that the camera platform is as level as possible, and try not to shoot in a windy place so that the wind doesn't shake things around. Use the self-timer as well (which I assume you're doing anyway if you're actually
in the photo).
Your lens exhibits a fair amount of barrel distortion towards the wide 18mm end (this means that straight lines look curved and people look funny; most wide-angle lenses do this, some more than others of course), so you want to place the camera somewhere that you can get everyone in the frame between the 28 and 55mm settings on the zoom. When I'm using my GF's IS kit lens it's usually in the 35mm position (where it's physically shortest) & I only change the focal length when I can't physically move to get the framing I want.
Depending on where you are, about +/-2 hours after dawn & before sunset is usually when the light is nicest. Avoid direct overhead midday sunlight or shooting when it's too dark or with the strong color cast and long shadows of late sunset. Cloudy days can actually be good for this sort of thing if it's just mild overcast as the shadows are a lot softer, the time of day matters a lot less, and no one is squinting or wearing sunglasses or a hat.
Shoot RAW, and
expose to the right if you're comfortable with that (jpegs are fine if you get the white balance & exposure right at the shot, but RAW enables you to fix things later). In general, it's a really good idea to shoot some practice shots in the light & environment where you'll be shooting and go check them out on a computer (not just on the back of the camera) to make sure they're acceptable. Netbooks are really handy for this sort of thing if you have one.
good luck & have fun.