Focus problem w/Sigma 70-200 f/2.8

[ottor]

Purchased 10/11 from Amazon - listed as used, but seller stated "Lens is new but I can't sell it that way - selling as 'used', but in factory fresh condition" .. I also have the warranty card.

Sigma 70-200 f/2.8 APO EX DG OS

Have never been happy with the focus on this lens and can't decide if it's me, or the lens.. Always seem soft and OOF a little. Even when I focus manually and use live view - zoomed in.. when I twist the focus ring, it gets more in focus and then without obtaining 'crack sharp', it goes blurry to the other side again..

Here are a couple of examples - both on a tripod with a 2 sec shutter delay.. f/10, 200mm, ISO 100, exp 1/25

The first pic is focused using Automatic

and this one is focused Manually ............. both on a tripod.

Both taken at 200mm, but I can guarantee you that a lesser focal length produces approx the same image.

First - do you see any focusing issues ?? - If so, is my warranty good with Sigma? I just want someone to check and see if there
is an issue with the lens, and the closest camera shop is 135 miles away .. Can/should I just send it to Sigma with the warranty
card and see what they say ??

thanks,

r

 

[ottor]

FOUND THE PROBLEM !! - 1st lesson - you get what you pay for.

77mm Vivitar Circular Polarizer ........ Cheap! = Lousy Image..........

replaced with 77mm Kenko Circular Polirizer - (RRRreallly NOT cheap) = but worth every Buck ! - That's all that was needed... the cheapo filter was
degrading the image!

Solved.. and now have fantasticly sharp images !

r

 

[rgregory1965]

Take off that filter, take it to f11 and sit back with a big smile...

f11 is the sweet spot on mine....

 

[rgregory1965]

here is one at f/2.8

http://www.thephotoforum.com/forum/just-fun/276182-still-playing-my-sigma-70-200-os.html

 

[rgregory1965]

View attachment 5299


A little sharpining.........