Revolutionary Sigma USB dock nears market; video shows how it works

Last fall, Sigma Corp. announced something that made its optics truly unique: a USB dock and software package that allows users fine-grained control over autofocus of new Sigma lenses. That product is now nearing availability, and the Japanese third-party lens manufacturer is providing some very interesting details about how the new Sigma USB Dock works.

It's a pretty revolutionary idea: we've seen camera bodies capable of fine-tuning autofocus before, but it's a function typically found only in more expensive camera bodies aimed at enthusiasts and pros, and even in cameras supporting fine-tuning, there are often limitations. Some cameras allow only a single adjustment that's applied to all lenses, others aren't capable of differentiating between multiple copies of the same lens model, and all have a hard limit on the number of lens adjustments that can be stored in the camera body simultaneously. Perhaps more significantly, though, the overwhelming majority allow only a single adjustment per lens. If your lens shows different degrees of front- or backfocusing with varying subject distance or focal length, you're out of luck, thanks to the one-size-fits-all adjustment. (Offhand, we're only aware of a few cameras -- Canon's EOS-1Dx, EOS 5D Mark III, and EOS 6D -- which allow more than one adjustment per lens, and even these only allow two adjustments: one at wide angle, and one at telephoto.)

 

Sigma's clever USB dock allows detailed control over microfocus adjustment and more.

By placing the adjustment function in the lens, Sigma answers all of these problems of in-body microfocus adjustment, and makes its lenses far more customizable to the needs of photographers. In the process, it gifts compatible Sigma lenses with a unique selling point, not available from any other manufacturer. With a compatible prime lens, you can now make adjustments to focus for four different focus distance ranges. On zoom lenses, you can do the same, but you're able to do so at four different focal lengths as well, for a total of 16 distinct adjustments.

And not only do your adjustments apply regardless of the camera body -- from the most affordable entry-level camera to the top-of-the-line pro model -- but they're also unique to the individual lens. Nor is there a limit on the number of compatible lenses you can adjust, since the adjustment is stored in the lens. That's great news if you're sharing a pool of equipment with other photographers. You may still have to calibrate the body as well to account for variance between different bodies with the same lens, but you should be able to get multiple copies of the same lens type to give similar results once bodies and lenses are calibrated. Even if you only have a single body in your camera bag, it's still helpful because it will allow you to calibrate autofocus in each Sigma lens you own specifically for that body, freeing up the in-body microfocus adjustment memory to calibrate your non-Sigma glass.

Nor is that all you can do with the Sigma USB dock. For Sports lenses, it also allows you to adjust autofocus speed and image stabilization to your tastes. You can also specify the range of the lens' focus limiter function, locking out any portion of the range that you don't intend to use, and reducing the chance of focus racking in the wrong direction. And the dock also makes light work of lens firmware updates, detecting and applying them automatically as needed.

Thus far, five lenses are said to be compatible with the dock, not all of them yet available at retail. These include the following models:

• Sigma 35mm F1.4 DG HSM | Art

• Sigma 30mm F1.4 DC HSM | Art

• Sigma 17-70mm F2.8-4 DC MACRO OS HSM | Contemporary

• Sigma 17-70mm F2.8-4 DC MARO HSM | Contemporary

• Sigma 120-300mm F2.8 DG OS HSM | Sports

Given all that it can do, the Sigma USB Dock's street price of just US$60 or thereabouts is pretty reasonable. Originally planned to ship last month, the dock was delayed just slightly, and is now set for delivery in early May. You can see a demonstration of the USB dock and its Sigma Optimization Pro software in use in the video above, and more details can be found on the Sigma USA website.