Re: If I go FF, will f2.8 be fast enough?
 

I used to shoot with 3 60Ds ,

Now its a c100 an 5d3

At the same wedding venue, at night, on the 60d 2.8 wouldn't cut it

But the c100 and 5d3 coped just fine at 2.8

Re: If I go FF, will f2.8 be fast enough?
 

I don't see the link between full frame and being able to shoot at very low light, all that matters is how "clean" the image looks at very high iso and in that case you don't need a full frame camera, a sony fs100, canon c100 will be just as good as a 5dIII to shoot with a f2.8 lens at very dark receptions.

Re: If I go FF, will f2.8 be fast enough?
 

You're talking about a different price bracket. He was asking about a 6D, which i much cheaper than the c100 or fs100. The lowlight of the 6D is going to be much greater than something similar to a 60D. The larger sensor in this price range of camera will make a difference in low light.