this is a part of plastic wonder, i have 2 lens promaster spectrum-7 19 35 f3.5-4.5 and this tokina 193.
I almost had a heartattack when i recieved this lens, i purchased this from a japanese seller MK-JAPAN, as i was using promaster which it is said optically the same but there is a difference in housing construction. the copy i recievedwas not sharp. the seller offer to refund knowing well that cost of refund is logically not possible, this is not the first lens from japan, i have AT_X pro 28-70 2.8 which had it set of problems. THIS SELLER JUST IGNORES AFTER SALE. HE KNOWS WHAT HE IS SELLING!!!!!!, i had to rectify the at-x 28-70 2.8 at a price, had it been one off would have understood but 2 lens!!!! is not a coincidence, beware of japanese sellers from japan may look discounted but in effect are bad copies. the body had a mark by a sharp instrument across the body, but thats not all, no infinity focus, random disengagement of f reading, autofocus. dust in the front element. The only option was then to disassemble clean the electrical contacts and dust, do the infinity setting remove extra washers. good 4 hours.
now sharpness is as good as promaster, micro contrast / colour is better than promaster, thus coating used has made a world of difference. but the wish still remains had i brought the at-x pro 20-35 2.8 its supposedly sharper than 193. for the price ok,
BUT did not serve my purpose of a sharper lens than promaster spectrum 7.
for the price guess its good better than kit lens.