This is a macro lens, we're not talking about the size of less than 1 cm we are talking for distance that is less than fraction of 1 milimetar, you have to controll focus with your body, and to shoot exactly in the right moment when focus point is in right place. This is the same rule for every lens with autofocus or manual focus. Tokina lenses are not my favorite, i like mostly Nikon, but Tokina 100mm macro? this is for me the best macro lens, as well as for you Sigma. Rings from Sigma this is a thin plastic as well as many other parts, interior parts are of lower quality. Tokina is from thick plastic, and inside most of the metal parts. Tokina is much stronger construction. Photos are extremely sharp. Tokina 100mm macro is good for every good photographer. When you break Sigma, you buy Tokina, she is from strong material, and the photos are pin-sharp believe me, I have nothing against you, neither against anyone else.