Not usually a big Sigma fan, but I got to admit, they've really brought their a-game in the "A" series. These are some pretty serious glass.
A photographer was trying to sell this lens the other day, for a reasonable price. I grabbed it. It was inevitable. Every forum, review or benchmarking site is talking about these lenses. The ultimate (Big) Bang for your buck. Don't take this the wrong way, these bad boys don't come cheap, although, they are considerably cheaper than their competition. Set aside weather proofing like a Canon L-lens, and you definitely have a beast of a lens. The majority of benchmarkers actually puts this lens on the top of the list, beating the Canon 35mm f1/1.4 L II in sharpness and vignetting. Its weight, build quality and ergonomics are spot-on. Arguably, the aesthetics might also be better compared to all the other 35's out there.
Now, let's cut to the chase. I definitely read and research a lot before purchasing something, and it was no exception this time. I was fully aware about the fact that the lens may probably require some micro-adjustments/firmware updates. The first thing I did after unboxing the lens was to do a wide-open test shot on someone's eyeball, at the minimum focus distance. I did about 10 shots, and as suspected, it did slightly miss. Since this is my first Sigma, I don't own a dock for the lens, yet. I had to make do with the lens calibration application in the camera for now.
I made a DIY lens calibration target, tethered my camera, and did a bunch of samples to do a thorough examination. I snapped 3 images in a row for every calibration step, just to verify the precision of each micro-adjustment performed. The first test image does confirm back-focusing. The next is the final test shot, after working my way back and forth. I ended up at -12.
The downside of only using the camera's micro-adjustment function is that you can only set a profile for a certain focusing distance. I tested both 40 cm and 1 m away from the target, and -12 did the job. Although, at infinity, it's just way off.
The image above shows the lens' potential when it focuses correctly (cropped; original frame below). I did use manual focus on this one though. I probably wouldn't use the lens professionally until I get my hands on a docking. Credible sources claim that this is a "normal" issue and you have to expect calibration when using 3rd party lenses. Users also claim that the dock really patches all its flaws - allowing you to do multiple adjustmens on different focusing distances. I'm pretty confident about the purchase and really believe that I'm gonna get good images with this lens; it's just a matter of getting the AF on track. Now... is anyone selling a cheap Sigma lens dock?