I have a photo shoot coming up that will have a group shot of 50-70 people in the atrium of a hotel out in the middle of nowhere. I am thinking of traveling with 1-2 Einstens with 13' stands and positioning them behind me and high with reflectors crossing the crowd. I will have adequate set up time, but only 20-30 minutes to get the shots. Traveling via air and rental SUV so I am a little limited in what I can carry.

Should I use umbrella's (I have 64")? Or diffusion socks on the umbrellas? Should I place a speedlight behind the group with a Lightsphere to give a little increase in the appearance of depth? I have Pocketwizards (TT1, 2-TT5 and 2-PowerMC2 and an AC3 zone controller).

I shoot with a Canon 7D and have a Sigma 70-200mm f/2.8, Canon 50mm f/1.4, Sigma 28-75mm f/2.8. I was thinking that the 70-200 might be better, but may have to use the 28-75mm.

How do you test something like this? Any advice would be appreciated.

The arrangement of the people will partly dictate where and how you set your lights. If you need to arrange people so that cross shadows are a problem, then it's best to use a "wall of light" configuration. If you arrange people so that shadows are not a problem, then cross lighting works pretty well.

You may also need light to help separate the people from the background, and a catch light.

Lighting is the one thing you cannot skimp on if you want best results.

Time of day can be a complicator, especially working with a true atrium. If you can obtain recent photographs of the area, that may help, especially if you can correlate with the sun's movements in the region.

Get to the site early, preferably the day before, and take some test images, without and with your lights. Borrow a couple people as stand-ins, just to test the light. Review the tests looking for shadow placement and thinking of best group arrangement. Make any adjustments to the lights based on your test results.

A light meter may be critical for some lighting setups.

You may wish to rent or borrow a super-wide zoom for this many people, depending on the size of the atrium and the positioning of the people in the group. 28mm is not all that wide on a crop 1.6x body.

Do plan on a small aperture for this many people, again, partly depending on how you organize the group.

Ziggy, You are always so helpful and full of constructive tips. The shoot will be in the evening so outside light is not an issue. I do have a Canon 10-22 and maybe that will be wide enough. I can arrange the people in an arc if necessary. I'm not sure I know what a "wall of light" is. I will do some research. I do have a light meter so I will put it to use.
Thanks again.

Originally Posted by r9jackson Ziggy, You are always so helpful and full of constructive tips. The shoot will be in the evening so outside light is not an issue. I do have a Canon 10-22 and maybe that will be wide enough. I can arrange the people in an arc if necessary. I'm not sure I know what a "wall of light" is. I will do some research. I do have a light meter so I will put it to use. Thanks again.

Here is a link to a lighting diagram for the "wall of light" (not mine), using umbrellas: http://submit.shutterstock.com/forum..._forum_438.jpg

Ideally, if you have a large and tall, white wall and ceiling behind you, you would point the flashes at the corner of the wall and ceiling to gain the best spread of light. Using umbrellas in reflective position, make sure that the flash head is well into the umbrella to give the widest spread.

Do have the flash as high as possible/practical and do use something white to cover the floor in front of the subjects to help with reflected light from the floor and to reduce "light poisoning" from a colored floor.

What you're trying for is something akin to "butterfly" lighting. The monolights are very high and provide light modeling by virtue of their height. If you want a little more differentiation, have one light set a bit brighter than the other.

The white floor cover gives you some fill. I would also use a speedlight/speedlite on the camera, set to a very low power, to provide some catchlight in the eyes.

If you see a lot of glasses in the group, forget the catchlight. If you do have a lot of glasses, have the subjects with the glasses pull their chin down a bit, but just a bit. You want to be able to see their pupils without glare from the flash. Taking glasses off is best. (This is a time when modeling lights are worthwhile.)

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If you want to place the lights on the flanks, I suggest at least 3 lights. In that situation the lights are still set very high (or bounced, if possible) to keep the shadows well behind the subjects (especially watch shadows from those subjects in the closer rows). The third light provides both fill and catch light and it is higher than the camera but shorter than the key lights. The third light is located very close to center and can be either in front of or behind the camera, even on the camera (but a little higher is better).