Shooting an event as a professional
This advice appeared in a lighting-related thread on the dpreview forums. The thread-opener asks about advice on the gear he should get (currently at enthusiast level), and gets a good eye-opener lesson.
http://forums.dpreview.com/forums/read.asp?forum=1025&message=39817789
It's has a bunch of very practical advice, but that's not really the point. The most important thrust is that you do not have time to fuck around. Easy to know, but it has to be applied rigorously, non-stop.
The event described is a volume shoot, not an art shoot. That doesn't mean there isn't an art to doing it well, but there's no place for fancy stuff here.
This is business, not just hobby shooting. You need to perform like a professional and use professional level equipment and procedures. Rent studio strobes. With bulk photography there are just too many problems with recycle time, batteries and overheating if you try to use hot-shoe flash units. The higher power, fast recycle time, and lack of overheating make using studio strobes a necessity. If you can't rent then buy AlienBees (Paul C. Buff), Flashpoint (Adorama), or Impact (B&H) studio strobes. Good companies, good products, and good customer relations reputations. Lots of third party diffusers and accessories will fit these lights, which can save you a lot of money. Use butterfly lighting, which will work for one person or a group. Shoot at f/8 or f/11. For your main light, place one studio strobe in a 3'x5' softbox - you probably want 600 Ws for this light. The distance of the softbox from the subjects should be between 6' and 12' and far enough away that you can evenly light a space about 6' wide. Position this softbox horizontally over the camera so that the nose shadow will fall about half way between the nose and the upper lip. Place a second studio strobe in a horizontal 3'x5' softbox below the camera as a fill light - a 300 Ws light will suffice. Adjust this light to provide 1 to 2 stops less light than the main. If you want a hair light use a 300 Ws studio strobe in a strip softbox with a grid mounted on a boom (make sure the stand is heavily sand bagged for safety) over and just behind the subjects. Use a 36" to 48" strip softbox. Adjust this light to about 1 stop less than the main light. It won't be ideal for everyone, but it will work well enough. The hair light should be just far enough behind the subjects that the light from it doesn't strike the nose or forehead of your subjects. The grid will prevent lens flare from this light. If you can't get a grid then cut a strip of black Coroplast the width of the face of the softbox and about 18" wide and clip it to the softbox to act as a gobo. Adjust it so that you can't see the face of the softbox from the camera position and so that the gobo is above the area included in the image. If you can't rent softboxes use a 60" white umbrella for the main light and a 43" one for the fill. Ideally you should stick some printed shoe prints on the floor to show your subjects where to stand, but since you are doing 1, 2, and 3 person shots you can't do that since they would show up in the photos. Place strips to both sides to define a line for the subjects to stand on and then strips with number labels for 1, 2, and 3 people between you and the subjects. These strip s will help get them into position as quickly as possible with a quick explanation from you. Be sure you have someone working with you to record information. Have pre-printed forms for names, addresses, phone numbers, and a space beside the names for your assistant to put down the image numbers. Check the camera after the first shot of each senior and be sure you read off the image number to your assistant.