I read about it all the time on line. I get asked about it often enough. My honest answer is....Let a pro do it.
"My friend has a wedding this weekend and he asked me to do the photos because their budget is very low. What should I do?" Honestly, tell them no. Please. Weddings, in my opinion, are the hardest thing in photography to do. A photographer goes out on a feature shoot and only needs 2 maybe 3 shots for the newspaper out of 20 to 100 taken. Fashion photographers will shoot hundreds of shots to get just a handful. Sports photographers will take hundreds, even thousands of photos just to get 10-20 great shots. Wedding photographers are expected to take 100-200 shots and have 100-200 great shots. And unlike many things shot photographically (I missed that dunk! No worries, there is 20 minutes left in the game) this is a once in a lifetime event.
"Oh, but I have a Digital Rebel and 2 lenses, and I got a 420ex flash. I have the gear, I just need to know what to look for." Did you know that wedding photographers like to be booked anywhere from a month to a year in advance? They will have meeting after meeting with the wedding party to go over details. Everything from standard group shots to special shots. They will have specific packages, and all the forms and check lists a bride and groom will need. They will make arrangements with the place the wedding will be held to come by and look things over. Talk to the people in charge to find out any photographic rules. Did you know that some churches will not allow flash in the sanctuary at any time? Some churches will not allow a photographer good access during the wedding. Some may not even allow photographs during the service. Preparation leading up to the wedding is big. Most wedding photographers will have 2 to 3 cameras, plus back ups. 2 to 4 light strobe set ups for group photos and 2 or 3 on camera flashes for candids. All the lenses they will need from low light wonders to short and long zooms. And the knowledge. Instead of reading a book on wedding photography a week before the wedding, they will have a number of weddings under their belts already, be well schooled in the art, understand what a bride wants, and most importantly be prepared for any situation. What happens if the place the wedding is being held will not let you use flash? Are your lenses fast enough? What if your camera fails the day of the wedding, or worse yet, during the wedding. Do you have a back up? Anything that could ever go wrong, will go wrong at a wedding, so it is best to know and understand this and make sure the wedding party understands it.
What about the photos? Wedding photos are processed differently than any other photos. A lot of post processing work will go into them to make the bride look perfect and correct any possible flaws in them from exposure, whiteballance, adding special wedding looks to them, and so much more. Many wedding photographers will spend 40 to 50 hours just working on the files alone after the wedding. Then set up proof books for the bride and groom to pick from. The final wedding albums can cost hundreds of dollars and should be perfect, as the books for the parents of the couple should be.
If you are approached to photograph a friends wedding, and you are not a wedding photographer or a pro, urge the couple to find a pro. Help them if you have to. If it is very close to the wedding, they may be out of luck, but if they discuss with various pro's their budget, they may be able to work something out. You could also help them by contacting a local photo club, and see if there are any pro's or semi pro's that could be of assistance. Even check with the local colleges. Students in advanced programs may jump at the chance to shoot a wedding for a lot less than a pro would charge.
Finally, if you absolutely have to shoot the wedding, take as much stress off of yourself as you can. Buy a bunch of disposable cameras and put them out at the reception. Let the guests take a majority of those photos. Go through the internet and find a check list that will cover all the shots you need to get. Bride & Groom, Bride with Bridesmaids, etc. Keep that check list with you and get every shot. Get at least three or four shots. Bracket if you have to. Go to the rehearsal. Go to the place the service is going to be held. Rent the gear you may need, like a back up camera and a couple fast lenses. Look at wedding photographers websites and get ideas from their images on how you should approach specific shots.
As many know, I am a media and sports photographer. But I will do weddings. I do them differently than most, but depending on the size of the wedding, my fees can range from $2000 to $10000. I do not like doing weddings because, while they are only a hour or two long, I will put close to two weeks of work into them. People see a price of $2000 for a two hour wedding and think, Wow...$1000 an hour. I should be a wedding photographer. Well that $2000 breaks down to $25 and that is before I subtract for the wedding album proofs and final prints.
So again, I say....Let a pro do it.