anyone go from a nifty fifty (50 1.8) to this? and was it worlds apart in terms of IQ? and speed?
Nifty fifty photo samples on here look pretty darn good too....
You're paying a premium for much better bokeh, focus accuracy (good copy of Sigma), build...along with FTM, HSM (similar to USM) and of course 1.4.
If you don't need any of those characteristics and you're happy with the IQ of the nifty, then save yourself the money.