Sigma 18-35mm f/1.8 DC HSM Lens Focus Calibration

Sigma 18-35mm

I received the new Sigma 18-35mm f/1.8 lens this week for testing. I pulled it out of the box a couple days ago and was immediately disappointed with the front focusing. It was way off at 18mm and a little off at 24mm and 35mm.

Thankfully, Sigma also sent along its USB control dock so I could calibrate the lens. I’m using a Canon 60D with it, so I don’t have the ability to make AF micro-adjustments in-camera. For users without this ability, the USB dock is the only resource for making the lens usable short of shipping it off to Sigma.

The dock works in conjunction with Sigma Optimization Pro software, which is built for configuring Sigma’s new line of lenses. The software is free to download and you don’t need a special password or license code (Thanks for making that easy Sigma). Just go to Sigma’s website here, pick your OS and download away.

Sigma Optimization Pro

It is quite easy and intuitive to use. Just plug in your lens and the software immediately recognizes it. You can update lens firmware or use other customization options.

Sigma Optimization Pro Customization Menu

In the case of the Sigma 18-35mm f/1.8 lens, the only customizations you can do are focus adjustments.

Sigma Optimization Pro Focus Adjustment Menu

Sigma has published the following video that shows you how to use the software.

As you can see, it is very straightforward.

You can also see in the above image that my test copy of the Sigma 18-35mm f/1.8 has some serious AF calibration issues with my 60D at 18mm. Check out the before and after image crops below from the center of the frame.

Sigma 18-35mm 18mm Pre-Calibration

Sigma 18-35mm at 18mm Pre-Calibration

Sigma 18-35mm 18mm Post-Calibration

Sigma 18-35mm at 18mm Post-Calibration

Holy crap! What a difference.

Now this calibration was performed at about a 6′ distance to subject. It’s late at night and I haven’t tested the new AF calibration at longer distances; however, you’ll notice from the screenshot above that the Sigma Optimization Pro software allows you to independently calibrate the AF micro-adjustment at 4 different focusing distances from minimum focus to infinity.

I know from shooting a few frames a couple days ago that the AF was way off at 18mm. I’ll test it again this week at longer distances and see if that +12 adjustment works. If not, I can make additional adjustments for the longer distances.

I also want to give a shout out to Focus Pyramid, who sent the dandy little cardboard focusing tool that I used to calibrate this lens. It just showed up on my doorstep one day and I’m glad I had it for this test. I think it is a little pricey at $25, but if you need to calibrate a lens, it sure comes in handy.

I’ll have more on the Sigma 18-35mm f/1.8 lens soon. I just wanted to take this opportunity to share my experience on dealing with the calibration of a lens with Sigma’s new USB dock. I think the amount of control the USB dock offers for $59 is worth it if you own one or more of the new Sigma lenses.