I'm going to buy the Sigma 18-35mm f/1.8. Is it worth spending $60 on the dock?

I've read in reviews that it's a bit unnecessarily complicated to use, but that's not my primary concern. Can I do just fine without the dock?

Edit: I have a Canon 60D.

7 Answers 7


You don't really need the dock until you need to install a firmware update, or until you decide you want to fine tune the lens. My suggestion: don't buy the dock until either of those situations arise. No need to spend the money now because you might want to do something later.

You can also rent the docks from some of the lens rental places (lensrental.com has it, borrowlenses currently doesn't) -- for something you only need to use once every year or two, that's a better deal than buying is and having it gather dust.

  • The cost of renting for a day or two plus shipping is about 2/3 the purchase price of the dock. If you need it, might as well buy it.
    – Caleb
    Mar 24, 2017 at 4:59

It depends on your camera and when updates are released. The point of the dock is to allow the firmware of the lens to be updated to support newer cameras and camera firmware updates. If the lens works just fine, you may never need the USB dock, but if an update to your camera comes out or Sigma discovers minor flaws in the lens firmware that need updating, then you will need the USB dock to apply the updates.

The reason that updates may be needed is that the lens and camera communicate with each other to make sure that images are captured correctly. The camera manufacturers don't disclose their protocols and don't pay attention to the needs of third party lens makers when making design decisions, so the third party companies have to work around that by reverse engineering and making their lenses respond in the way the camera expects.

If they either made an error in reverse engineering or your camera is updated to expect things slightly differently, then the lens may either stop working entirely or simply have a reduced level of functionality or speed. That's when the third party lens maker would normally release a new firmware to correct the issues.

  • I had a case (for a flash, not a lens, but same thing) where it would not work on a new body, but they no longer supported that model with firmware updates. Another reason not to get the dock until needed! BTW, my Metz flash has a normal USB "B" jack for updates and doesn't need some special adaptor: everyone should do that.
    – JDługosz
    Dec 30, 2014 at 21:41

Another reason to buy Sigma USB dock is to make on your copy of lens fine tune the focus. Of course this can be done on some cameras too, but if you tune with dock you will get tuning independent of the camera

But before buy better test your lens and if you are OK with the focus do not buy :)

And see the answer of @AJHenderson about the other reason to buy USB dock

  • Hmmm interesting. I learned long ago from Lensrentals that fine tune focus adjustments are meaningful for a lens and camera in combination. What does it mean to fine tune focus independent of the camera?
    – mattdm
    Dec 30, 2014 at 16:40
  • @mattdm, USB dock help you make microadjustments of focus in particular lens. As nothing is perfect for some focal lengths (and some focal distances) the focus of your copy can be not very precise so this dock help you readjust it (in the lens). You can get more detailed info on the Sigma website: sigmaphoto.com/product/sigma-usb-dock Dec 30, 2014 at 17:02
  • 1
    Nice additional use. I wasn't aware of that. (I shoot entirely on first party lenses personally.)
    – AJ Henderson
    Dec 30, 2014 at 18:01
  • For some compatible (only one at the moment) you can (according to the Sigma website) adjust Autofocus speed, Object Stabilization (IS) behavior and focus limiter. But as they are available only for 120-300/2.8 i do not mention them :) Dec 30, 2014 at 18:06
  • With zoom lenses you can calibrate different focal lengths along the zoom range independently. Some Canon body/lens combinations allow you to calibrate the widest and longest focal lengths independently, but then it interpolates the amount of correction for all focal lengths in between in a flat line. (I.e if your 70-200mm has an AFMA setting of -4 at 70mm and +6 at 200mm, the camera will use +1 (1/2 way between -4 and +6) at 135mm (1/2 way between 70mm and 200mm). The new Sigma system with the USB dock allows you to create several other independent points.
    – Michael C
    Dec 31, 2014 at 3:45

I bought the dock as I have two Sigma Art lenses for my Nikon. One of the lenses was used with my previous Canon and worked perfectly without adjustment. However, on the Nikon, both lenses need fine tuning for autofocus and the hub allows for that adjustment. It's better than using fine focus adjustment in camera as you can adjust four different focal distances with the hub (at four different focal lengths with a zoom lens). It's a pity Sigma didn't simply provide a usb port on the lens itself though as I did resent paying extra to make it focus correctly with the Nikon.


One small reason to own the dock is that it records the serial numbers of the lenses you've attached to it - you can see the lenses listed even with the lens disconnected. You could use that in case of theft for example, to report the serial numbers for lenses stolen.


I'd buy the dock, after just having brought a 24mm and 35mm Art, both needed calibration, you buy some of the best glass around it's important to get the best out of it!


You also get the ability to add new autofocus algorithms with the firmware updates. I have never owned a lens that didn't need some focus fine-tune adjustments, and almost all zooms need multiple (different) adjustments at different focal lengths and distances. Only Sigma lets you do this, and only with the USB dock. Anybody that cares about quality should get one, especially since they're dirt cheap.

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