Dear Teachers and Friends.
Sir/ Madam, I am a crazy Canon fan, and buy any Canon Lenses and Canon Cameras that I like with out Thinking, Until I am the member of CR. for 4 months---Yes, I Must ask my Teachers and my friends in This Great CR. before I buy some thing.
The Question :
I already have one of the good Sigma 50 mm. F/ 1.4, And I just use 2-3 times after I buy 8-10 moth ago, Do I need This Awesome Used Canon EF 50 mm. F/ 1.0 L ( $ 3,750 to 4,100 US Dollars-Fron E-Bay)---For show-off to my friends as the fastest Lens( Ha, Ha, Ha), Or But the new Canon EF 50 mm. F/ 1.2 L USM ($ 1,620)--for use and beat Sigma 50 mm F/ 1.4 in Shallow DOF and better Bokeh.
Thanks you so much for answer my stupid question.
I must admit that I too was interested playing with a f/1 lens in near darkness after reading that. The following link gives a good comparison between the various 50mm options. I had borrowed a Canon 50 f/1.4 before getting the 50L f/1.2, and the f/1.4 had inconsistent focus from f/1.4 to f/2. The colors were also less pleasing. The Sigma is said to fall between the two Canon offerings, but the link below shows that the resolution among the three lenses are similar and are clearly better than the f/1.0. If you're happy with the AF of the Sigma, then I don't see a reason to switch. If you're not, then the 50L f/1.2 is a good choice. You'll get better bokeh, a 1/3-1/2 stop in speed, but the price for that upgrade is pretty steep.
The 50L f/1.2 is not about resolution (not as sharp at 100% as other fast primes) and the 50 f/1.0 is even less about resolution. But the effects of the f/1 shot wide open are special. Definitely a lens that I would like to try, but not buy...