de Sigma i never try b4 but de tokina i did try afew times fm my I.R buddies..
hmm i mus say its not a sharp lens as i tot..have to shoot above F4 to get a decent sharpness.. worst of all..u can see thick C.A on bright area.. i end up biught my a tokina 12-24mm F4
well, above all its jus wat i felt when i do some test during I.R outing wif them.
