Canon lens advice for an indoor birthday party

[theboybg]

Hello,
Long time reader here but relative newbie to the forum !

I'm planning to shoot a friends (adult) birthday party at the weekend and need a little advice. Basically the venue is a bar with private room that has bowling (10 pin!) lanes (google: All Stars Lane in Bayswater, London) so light levels are fairly low and there will be a fair bit of movement.

Currently I have:
Canon 40D
Canon 50mm f1.8 lens
Canon EFS 17-85mm f4-5.6 (kit lens)
Canon Speedlite 430EXII

Was thinking of renting a lens for the weekend, something a little faster and more versatile to cope with the event & hopefully not have to rely on flash - as I'd like some more natural 'non-posed' style of shot. Am I asking for too much?

I was thinking about renting one of the following:
Canon EF 35mm F1.4L
Canon EF 85mm F1.2L
Canon EF 24-70mm F2.8L

Any advice greatly appreciated!

Thanks,
theboybg

[inkista]

Of the three, I'd say go for 35L--particularly if you want to get some environment/context and full-length shots. But I'm a prime shooter, and I love 35mm as an all-purpose focal length on a crop. I'm sure more folks will tell you to plump for the 24-70L. Both are great choices.

But the 85L, not so sure. Handle it before renting, if you can.

It's nicknamed "the Canonball". It's about as wide across as it is long, and it's one honking big piece of glass to be sticking in someone's face. If you want to be inconspicuous and unnoticed while shooting, the 85L is not the way to do it. Also, f/1.2 can be an absolute bear to focus accurately. And the 85L focuses by wire, and is notably slower than most other lenses to find autofocus. If you plan on hanging back and shooting from a distance in the heat of the moment, I'd actually recommend the 85/1.8, 100/2, or the 135 f/2L instead. They'll still get you some nice dreamy bokeh.

[zona5101]

another vote for the 35f1.4. In low light the 2.8 won't be the problem solver you might think. I'd rather have the extra 2 stops so i can shoot at a faster shutter and/or keep the iso from hitting the top end.