from my film days...that I have not really used much. I have not used any other 12-24s (the nikons or the Tokinas). How do you think the Nikons and the Tokinas compare to the Sigma 12-24? I know about the filter and bulk issue, how do you think the quality is on a DSLR compred to the others. I am thinking about getting back to WA lens shooting, and cannot decide whether to sell the Sigma (I do not shoot film anymore) and get the tokina or just keep it.