Sigma 24-70mm Lens Service / Clean

[dan.browne]

June 26, 2012 at 9:42 pm

I have a Sigma 24-70mm Lens and since I upgraded to my Canon 7D sometime last year I have noticed that it has become “soft” in its focusing. It is as if it is focusing just in front of or behind where I want it to. Even though throughout the view finder it appears to be focusing on the correct portion of the image. Also I think there is some dust inside the lens.

Where would you recommend that I get it serviced/cleaned? And if you have any idea of how much this would cost to get done!

thanks a million as ever for any help/advice

[alanhunt99]

June 29, 2012 at 2:03 pm

Dan
Have you tried to do a micro adjustment on the body?
Menu; C Fn III ;adjust by lens.
What I have done is focus on an object with AF and then turn off AF and switch to live view and zoom in.
If you can focus it better with the manually after that, then you are probably back or forward focusing.
You can do a micro adjustment and retest. You can’t do any harm as you can always reset the adjustment.

There is also a chart that you can use if you want to go down that road. I found it excellent and was surprised how far out some of my lenses were. My canon 24-105 f4 needed an adjustment of +12. Even at f4 it needed ajustment.

The chart can be found at:
http://focustestchart.com/focus10.pdf” onclick=”window.open(this.href);return false;

Hope this helps

Alan