Only 1 lens

A friend of mine owns the 28-70/2.8L on the 5D2 strictly for photos, and he's not thrilled with the sharpness. But for video, it should be no problem.

I don't have it but probably the 24-105 IS. It gives you wide and decent zoom with IS. This I think is THE best all round lens made by canon.

I'd be interested to hear a comment from someone who does have it. On the 5DM2, does the camera's inherent low-light capability make it practical? On the 7D I can say, from experience, it would be too slow.

I don't have it but probably the 24-105 IS. It gives you wide and decent zoom with IS. This I think is THE best all round lens made by canon.

Try to focus in low light with a f4 lens. You will be less than thrilled.

IMHO, the 24-70 f2.8L is the best lens for a one lens does it all kind of compromise, as the OP is asking for. The 24-105 f4L is a good lens, I would say for travel purposes for example, but not as the only lens to have for general purposes.

No Contest, My Zeiss 100 f2 ZF.

"Try to focus in low light with a f4 lens. You will be less than thrilled. "

Wouldn't the exposure simulation in the LCD make it the same brightness as the final exposure?