Question about Sigma 12-24 lens
I am thinking about buying this lens but confused over the different variants of this lens sold in the market. I am planning on going in for the Canon or Pentax version. Some copies of this lens seems to have a manual aperture control wheel in the rear while some dont seem to have them.
I have the following queries:-
1.Are all versions of this lens Full frame or only some? Incase they are how do I find out?
2.If there is an aperture control wheel on the rear is it an old or new version of this lens? Which one is sharper at wide apertures?