I'm come across something I didn't expect. Tonight I'm doing some pics for a friends 21st birthday party and looking at the venue's website I was feeling ok about using bounce flash off the ceiling which I've had plenty of success with in the past. 580EXII on the 7D.

But I just got a call letting me know that the "ceiling is a reflection of the floor". It is a black glass that sounds highly reflective.

So I'm not sure what to expect now. I'm thinking I'll just have to try and make use of walls a bit more, or try and use a wide zoom on the flash head and not bounce it directly above my subjects?

I'd welcome any advice!?!?