Which Lens For These Photos?

I need to take a bunch of business photos like this using our Canon 5D MarkII:

http://www.mackaysposi​to.com/ (scrolling photos on home page)

Because they will be taken inside a small office I'm worried that a 85 f/1.2 might prevent me from getting everyone in the scene as I won't be able to get back far enough. So then I thought about the 24-70 f/2.8 but am concerned that 2.8 won't give me a shallow enough depth of field. Maybe the 50 f/1.2?

85mm f/1.2
50mm f/1.2
24-70 f/2.8

Any advice?

24-70

Thanks! That's what I was hoping I could get away with using. It's a much more versatile lens. I can think about buying some prime lenses later.

Primes - 35 through 85. 24-70 is okay, but you'll need to jack up the ISO if light is bad. Bring some reflectors to lighten the raccoon eyes.

Thanks. We plan to bring our own lighting. I can't afford to buy a 35, 50 and 85, so I guess the 24-70 will have to do.

Whatever gets you the composition you want from at least 6' away.

I would avoid going below 28mm, though...35mm, ideally. People on the edges start getting too distorted.

I also think that 24-70 would be a wise choice. It is a very good lens in terms of sharpness (for a zoom lens) and image quality.

In a close environment like this, I'd suggest a zoom lens over a prime for flexibility.

Thanks again for all the replies. I think I'm going to borrow my friends 24-70 f/2.8. I'm waiting to purchase my own until Canon to releases the mythical new 24-70 w/IS.