I would like to pick up a fast prime for indoor available light use, and I haven't quite decided on 50mm or 85mm. I got pretty used to a 50mm on a 1.5 crop (~74mm) but I do admit at times I was scooting backwards to get my entire kid in the shot, but only 3-5 feet. I'm worried 85mm may be too tight. On the other hand 85mm is a focal length I don't currently have with the 24-70. 50mm on the FF is very nice since the 24-70 is 'defaulted' on that FL, I end up using it more often. The 50mm focal length requires me to close in a bit on my son to fill the frame, but its nice as I can get wider shots when company is over, etc. I'm also probably deciding on the 85mm f/1.8 vs. the 50mm f/1.4 since they are so similarly priced. I'm interested to hear from other full frame owners on their experiences and opinions. Thanks!