mmurph Offline Upload & Sell: On
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Roger Cicala at Lens Rentals has a pretty quick and pragmatic post on using the dock to adjust his lens:
http://www.lensrentals.com/blog/2013/06/sigma-optimization-pro-and-usb-dock
Basically, shoot at the different distances and look at where the focus falls. Once you have been through it once or twice, it is pretty easy.
He also makes the point that the Phase Detect Autofocus in most cameras has some slop. So to test just the lens and not the autofocus, use Live View and/or Live View with manual focus:
http://www.lensrentals.com/blog/2014/02/why-you-cant-optically-test-your-lens-with-autofocus
Sigma has excellent customer service and a 4 year warranty in the US. (Can't check your location on my phone right now.)
The lens must be less than 4 years old. If the shop sold it new, they may be able to send it in for tuning under the original sales receipt and date.
I **love** my Sigma 35 1.4 Art. I shoot it wide open even under low light/high ISO and it has been perfect. There are a number of "best practices" to help improve your keeper rate at 1.4:
1. You can't focus and recompose!!!
2. Use a cross type focus sensor directly where you want the focus point.
3. If you focus and hold, waiting for the right expression, use Servo Ai/ Continuous focus. If you lean or sway, or the subject does, you are changing by enough to blow your depth of field.
When I first shot my Canon 85 1.2 wide open, my keeper rate with focus and recompose was under 50%. This takes practice and knowledge to use effectively!
I have decided to whittle down my kit to only **the best** glass. So far that means the Canon 24-70 2.8 II, 70-200 2.8 II, and the Sigma 35 1.4 Art.
Looking forward to a lot more from Sigma in the Art line!
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