canon 50mm f/1.4 vs 85mm f/1.8

[DBlack]

I'm ready to get me a nice prime lense and have narrowed it down to the:

Canon 50mm f/1.4
Canon 85mm f/1.8

The primary use of this lense will be for portrait; body and closeup. I've read a ton of reviews on these, but trust the 'reviews' of the forum a bit more.

Which has the better image quality overall?

Using a Rebel XTI, how much room would I need to take full body pics/portraits? I suspect that due to the 1.6 crop, I would have to be backed up, but don't know how much?

Image Quality is my number one priority for this lens.

thx in advance for your advice.

 

[Early]

I'd give the advantage to the 50, but I seriously doubt you'd be able to tell the difference.