Some high iso photos from 3200, 4000,5000 and 6400 from my 7D. Len used was Canon 24-105mm F4 IS L.
File size is medium. Body noise reduction was set to standard, Light optimisation set to auto.
Photos straight from camera. Please do NOT use my image without my permission. I appreciate if you link to this page instead.
#1 - ISO 3200 (click on image to view full size)
#2 - ISO 4000 (click on image to view full size)
#3 - ISO 5000 (click on image to view full size)
#4 - ISO 6400 (click on image to view full image)
I would say the ISO 6400 is pretty usable for web especially when we need to resize the photo. I don't see any drop in sharpness which is good.