Quote:The Sigma looked good to me.....just a question of checking for de-centering after purchase and returning for another if it's not good.Well, then was then and now is now... that lens model is from the iron age! I almost ended up buying one 10 years ago. Glad I skipped on it - it was way before even cheap lenses started becoming pretty good.
The construction levels are way above some of the old EX series lenses..........
I've stripped down an old 28-70 EX F2.8 and to be quite honest the construction was not far away from just plain cheapskate.....many self tapping screws into plastic........and not much in the way of metal..... the old AF screw-drive pinion drives direct on to the inside of the lens barrel where the teeth were just part of the barrel moulding.......with no manual AF provision, inadvertently holding the barrel in AF mode easily strips the gears and is too easily done....which is what had partially happened. Add to that a super thin rubberized outer coating which was falling off and all in all there's nothing to justify their EX category.
Their new upgrades in optical performance has been followed through in the mechanic revision of their lenses.....very nice too!
By the way, I have a Sigma EX lens from that era - or even older, because it's not even marked DG - and it's pretty good with metal outer construction (no idea about the inside - I'm smart enough to never try disassembling anything, since I got a veritable hand of thumbs!) and HSM focusing (pretty fast and silent, but not entirely accurate). I'm talking, of course, about the good old 14/2.8. So the EX lenses were not all born equal either... (I truly shudder to think what the non-EX ones were like back then...)