---
product_id: 1747469
title: "USB Dock for Canon"
brand: "sigma"
price: "€ 100.30"
currency: EUR
in_stock: true
reviews_count: 7
category: "Sigma"
url: https://www.desertcart.hr/products/1747469-usb-dock-for-canon
store_origin: HR
region: Croatia
---

# Multi-point zoom focus calibration Firmware updates via PC Precision AF tuning USB Dock for Canon

**Brand:** sigma
**Price:** € 100.30
**Availability:** ✅ In Stock

## Summary

> 🎥 Tune your Sigma lens like a pro — because every shot deserves perfection.

## Quick Answers

- **What is this?** USB Dock for Canon by sigma
- **How much does it cost?** € 100.30 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.hr](https://www.desertcart.hr/products/1747469-usb-dock-for-canon)

## Best For

- sigma enthusiasts

## Why This Product

- Trusted sigma brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Seamless Firmware Updates:** Keep your Sigma lenses future-proof with easy firmware upgrades via USB dock and free software.
- • **Intuitive Software Interface:** User-friendly Sigma Optimization Pro software makes complex lens calibration accessible and addictive.
- • **Customizable Autofocus Behavior:** Choose between speed, accuracy, or balanced AF modes tailored to your shooting style.
- • **Unlock Pro-Level Autofocus Control:** Fine-tune focus across multiple focal lengths for razor-sharp images, beyond camera body limits.
- • **Universal Dock for Compatible Sigma Lenses:** One dock supports multiple lenses in Contemporary, Sport, and Art series—streamline your workflow.

## Overview

The Sigma USB Dock for Canon is a compact interface device that connects compatible Sigma lenses to your computer, enabling precise autofocus calibration across multiple focal lengths, customizable AF and optical stabilization settings, and firmware updates. Designed for Contemporary, Sport, and Art series lenses, it empowers photographers to overcome factory tolerances and camera body variations, delivering sharper images and personalized lens performance through the intuitive Sigma Optimization Pro software.

## Description

Update Lens Firmware

Review: A brilliant idea by Sigma - This is equivalent to reviewing a movie. The details of the delivery media (say a DVD) is much less interesting than the movie itself. The hardware, in this case the USB Dock you're considering purchasing, just works as expected. You attach it to your supported lens and plug it in to your computer. Settings you make in the software is transferred to your lens. End of story. This review focuses on the entire solution, particularly the software - its design and how well it addresses the problem at hand. Top camera bodies from Nikon and Canon (and possibly others) support lens focus fine-tunning. Notice that, due to fabrication tolerances, this fine-tuning is necessary to match a particular lens to a particular camera body. I have tunned all my lenses and can attest that it does make noticeable difference in image quality. The problem is: You can only set one value per lens. Say your body/lens combination backfocuses. You set a negative value, essentially telling the camera to front focus a bit to compensate. That works well for a prime lens, but not for zooms. What if the zoom back focuses at the short end of the range but front focuses at the long end? Sigma had a brilliant idea: move the tuning process away from the constraints of the camera and into a computer where it can be done properly. Not only it allows fine-tuning the focus, it also allows one to customize a (supported) lens for different behaviors. In the case of my Sigma 120-300mm f/2.8 there are 2 variables, namely Autofocus={speed priority (fast, a bit jumpy), accuracy priority (smooth but slower), default (somewhere in between)} and Optical Stabilization (OS)={heavy, light}, for a total of 6 possible combinations. You'll need this dock and the accompanying software to set your preferred custom behavior into the lens. There is a third function: one can update the firmware in the lens using this dock. Firmware in a lens... that's a first for me. The fact that they had to put microprocessors in a lens to implement this in-lens customization (and thus needing firmware updates) should be transparent to the user. So I won't count this firmware update function as neither a pro nor a con. It must be noted that Sigma's solution surpasses the current state of the art (from Nikon/Canon/etc), in that you can set not only one but at least 4, and up to 16 values, depending on whether the lens is a prime or a zoom. The price for this much flexibility and control is the escalating amount of trial and error steps (set in computer, test on camera, repeat...). It's almost overwhelming and addictive. And I like it. The software (not supplied with the dock, but it's a free download) is well executed, with a simple and intuitive presentation. There are some defects here and there, mostly text that get truncated because they don't fit in a window panel that can't be resized. Fortunately, one can bring up the help and read the message in its entirety there. I'd say the software is so intuitive that there's really no need for help at all. Most of the text in the help is a copy of the text you see in the software anyways. It would've been nice if they elaborated/reworded what you see on the software panels. For example, when setting the OS customization, you can pick from Dynamic View Mode ("This mode offers a recognizable OS effect to the image in the viewfinder. This helps to ensure the composition of images quickly.") or Moderate View Mode ("This mode offers an excellent compensation of camera shake, and achieves very smooth transition of the image in the viewfinder. The composition of the image remains natural even when the angle of view keeps changing."). The explanation in the help is exactly the same as in the software. Can you tell which mode has more OS and which has less? I used the terms "heavy" and "light" above, which are more descriptive than "Dynamic" and "Moderate". If you want to know... Dynamic View=heavy and Moderate View=light. The one con that I can think of is this: while the software automatically recognizes which Sigma lens you docked, it has no knowledge of which camera you intend to use the lens on. The software stores only one setting for each lens. It would be nice if Sigma were to add the ability to memorize several settings for a particular lens (each corresponding to different cameras) so that they can be easily and quickly recalled and loaded into the lens. On the whole, I'd say this USB Dock is likely a must have item if you want to get the most out of your Sigma lens, especially a zoom lens (like the 120-300mm f/2.8). This is the best tutorial on how to use the Sigma Optimization Pro software that I know of. http://vimeo.com/64665246 Update 4/01/2014: Sigma has since introduced 7 new lenses (including the 3 for mirrorless cameras) and none of them support/use this dock. I don't know why they've chosen that route, but the end result is that, at this time the value proposition of this dock isn't what Sigma suggested it would be. I'm changing my review from 5 to 4 stars until I see more lenses compatible with this device. Update 9/14/2014: Per Sigma's website[...] all 8 (A, C, S) lenses support this dock. Only the mirrorless series of lenses don't support this dock (I don't know why that must be the case; it seems like it'd be a good idea for all lenses to be focus fine tune-able, mirrorless or not). They must have forgotten to update that site last time I checked, which led me to my conclusion in the previous update. Their site has been corrected now. I'm changing my rating back to 5 stars.
Review: Worked well to tune sharpness Sigma 18-300 zoom lense: Now I am happy! Q&A for you - This is a very useful tool for Sigma zoom lens, or for any Sigma lens if your DLSR does not have AF microadjustment. I will answer several questions which you probably are asking yourself: 1. Which one to get? "Sigma USB Dock for Canon" means a USB dock for Sigma lenses with Canon mount, i.e, lenses designed to work with Canon cameras. If you own a Canon camera, buy a Sigma USB dock for Canon. If you own a Nikon camera, buy a USB dock for Nikon. Do not forget that this dock only works with Sigma lenses, and only with selected Sigma lenses. 2. Does it work with all Sigma lenses? NO! It only only with most Contemporary, Sport and Art series lenses. Sigma web site has up-to-date list of compatible lenses. Search for for "Sigma USB Dock" on Sigma web site, or go to Sigmaphoto web site and navigate from Home to Accessories -> Lens Accessories -> Category: Miscellaneous -> Sigma USB Dock. There, you will find the list of about 26 lenses supported by the dock, a link to download the free software, and link to tutorials. Scroll all the way down to the bottom of that page, below the table with compatible lenses, to find the link to the manual. 3. Does not work with Nikon or Canon brand lenses? NO WAY! The dock is just the means for the Sigma software to talk to the electronics in the Sigma lenses. It only works with Sigma brand lenses, and only with selected ones, which have this capability. 4. What is lens autofocus (AF) adjustment? Most DSLRs, with the exception of mirrorless ones, have a separate sensor for autofocus. It is possible and happens quite often that due to tolerances in manufacturing of camera bodies (and lenses), the focus which appears to be perfect to the autofocus system turns out to be slightly out of focus on the image sensor. There are two way to adjust for it. High end DLSRs have a so called "AF micro adjustment" (the exact term for it depends on the DSLR brand). This adjustment in the camera itself can even be lens-specific, i.e., you can program your high end camera body with individual AF adjustments for each lens you own. Sigma went one step further, they included AF adjustment into software/firmware of their lenses and provided an option to use different adjustments for different focal lengths. This works great with long range zoom lenses, which may front-focus on low end of the zoom range and back focus on the high end, or the other way around. You get multiple adjustment points instead of a single one on a camera body. 5. What does this USB dock do? It enables you to update lens's firmware and to program autofocus correction factors into the lens. It is just an interface between your lens and your computer. Basically, it is a dummy plug which matches your camera brand's mount with contacts to connect to contacts of the lens and with a USB interface. 6. Is calibration done automatically? How long does it take? Unfortunately, it is a tedious manual work. The dock is just an interface between your computer and lens's firmware. You do all the work and then use the dock to upload updated parameters into the lens. The dock does not measure anything and does not calibrate anything on its own. You buy a focusing target, install the free Sigma software (free download from Sigma web site), connect your lens, write down the focal lengths and distances from the table provided in the software, then grab your camera, set it on tripod, set it to center point AF, single shot AF, center point metering, set up the camera at one of the four distances listed in the Sigma software (you cannot change those, they are given to you), and take picture of the focusing target for each of the zooms listed in the table (if applicable to your lens) and each of the distances. If it is a single focal length zoom, you will only take 4 images from different distances. If it is a zoom lens, you may have to take as many as 16 images, a matrix of four focal lengths and four distances from the target. Then, you download images from the camera and examine them closely on the computer screen. The AF target has a tilted scale (looks like a ruler) which enables you to make a judgement where the best focus is - is it right at the center, where the focusing plate is, or is it behind the area which you focused on, or in front of it, and by how much the center of the area which is in good focus is shifted relatively to "zero". It is fairly easy to see. Once you've done it, the next step is to enter some numbers into the table in Sigma software. The numbers are in focus units, not in cm or inches. They probably are just steps of the stepping motor in the lens. They do not directly correlate with distances and Sigma does not provide any guidance as to how to correlate what you see in the pictures with required changes to focus parameters. All you know that you should increase the focusing parameter in a positive direction, e.g., from 0 to 5 (the total range of adjustment is from -20 to +20) if your camera front-focuses and you want to move the focal plane further away from the camera, and reduce it (e.g., from 0 to -5) if your camera back-focuses and you need to bring the focal point closer to the camera. Basically, you end up doing bracketing through several iterations, first making large steps and then smaller steps to dial the focus in. With my lens (Sigma 18-300), a focus step was roughly matching 1/2 of a centimeter on the inclined ruler of the focusing target with shorter distances between the lens and the target, but this is a very rough guideline. If you see that focus is off center, change the parameter by 5 units in the proper direction and check in the next round of measurements if this was enough. If not, change again and take more pictures. If you went too far, take a smaller step back. Repeat until you are satisfied. In my case, with Sigma 18-30, it took about 5 hours for 6 iterations for my son and I to complete the task to a reasonable level of satisfaction. 7. How do I know that I need to calibrate my Sigma lens? The indications are: soft focus across the whole range, or on the high or low end of the zoom range. Images come with sharp areas not quite where you focused on, i.e., on something a little closer to you or a little further from you than the focal point. Also, if your camera has "live view" (which is focusing using image sensor instead of autofocus sensor), you can compare images taken in live view and in standard mode. If live view images are noticeably sharper, your AF requires tuning. 8. Where to find more information on how to do it? Sigma has a manual for the software (fairly lousy, I must say) and a tutorial video. I found videos posted by Digital Goja very helpful. Those can be found by Googling for "Dijital Goja Sigma USB dock video". Finally, an article which can be found by its title, "Lens Calibration Explained" (just copy this into Google) was very useful to me to understand what I was supposed to do and why. This article does not explain the Sigma USB dock (instead, it discusses adjustments of AF on the camera body), but is very helpful to understand the rest of the process and tools needed. 9. Do I need anything else, beyond the Dock? You need a DSLRKIT or any other lens focus calibration tool. You can get it from desertcart for $6 - $9, or even download drawings from the Internet and make a target from cardboard at zero cost. You need a tripod to mount your camera. You need a source of bright light to illuminate your target if you do it indoors (you can do it outside and use sunlight). You need a tape measure to measure distance from the target to the camera. Finally, for measurements with "Infinity" distance, you need to find something relatively small across the street, like a house number or something. With "Infinity", there is no inclined ruler on the focusing target to access where the focal point is, you go by sequential trial of several settings and comparison of images. 10. How do I deal with measurements at "Infinity"? I just took pictures at several values of parameters entered into Sigma sofware (like 0 , 5, and 10) and compared the pictures, to find the sharpest. You cannot use the target at Infinity (they are too small - of course you can make your own giant one!), and might struggle at 20 feet, too. Just take pictures of something with sharp contrast and small to medium features at several focus correction parameter values, compare them, and identify the best sharpness setting. 11. Is the process of calibration worth it? If you suspect that your lens is not a sharp as it should be, this USB dock will take your lens to the next level. The difference is between you being frustrated about your purchase and being happy. At least, this is how I felt before and after calibration. I changed from "I may have to return this lens, my cell phone shoots much sharper pictures" to "It works very well" within 5 hours. Some vendors sell USB Dock in package with Sigma lenses. 12. What is in the box? USB dock, a USB cable, warranty card, and some kind of manual which I did not even open. 13. How to set the camera for shooting test images? Very important! Single point (center) AF. Center point metering. Single shot AF. ISO set to a low value, e.g., 100 or 200 to reduce noise in the images (helps to see the sharpness level better). Shoot in Aperture priority mode with F-stop set to the lowest possible value allowed by the lens for a given focal length. 14. Which Sigma lenses benefit most from AF tuning? Long range zoom lenses (which may back-focus on one end of the zoom range and front-focuse on the other end) and very bright lenses with very low values of F stop, like 1.2 or 1.5, which have a very shallow depth of focus. 15. Do only Sigma lenses require tuning of autofocus? Apparently, no. Apparently, all lenses of all brands can benefit from it. All pro level cameras have a single-parameter AF tuning built into the DSLR bodies. Sigma is different in that it took one extra step forward and created a solution for tuning across the whole range of zoom. This increases the precision of tuning. No other manufacturer offers USB dock for lenses. Sigma dock does not work with any other brands of lenses. Not even with older Sigma lenses. It is a very new technology. 16. Do I need to have a Pro level Camera to feel the difference, or need to use a USB Dock? As I learned it hard way, it is just the other way around: if you have an entry or mid level camera (I bought Canon Rebel T7i) which does not have a micro adjustment of autofocus, tuning of the lens with USB dock is the only option, short of replacing the lens over and over again until you find the best match to your body. It is a combination of body and the lens that determines sharpness. The same lens may be perfectly sharp on DSLR body A and not sharp on DLSR body B. Go figure. 17. Is it just the lens that determines if focus needs be tuned? No, it is a combination of the lens and the body. The thing is, most DSLR (with the exception of mirrorless DSLRs, which never need focus tuning) have a separate sensor for autofocusing, with an additional mirror which redirects the light from the lens to the autofocus sensor instead of the image sensor. If the distance which light has to travel to the autofocus sensor is different than the distance to the image sensor, just by a tiny amount, the AF sensor will decide that the image is perfectly focused, but the image sensor will see a blurry image. Lens might also have manufacturing tolerances which could contribute to operation of autofocus. The end result depends on combination of individual parameters of lens and body. Lens A may be super sharp on body X but not on body Y. 18. If I have a micro-AF adjustment on my DSLR, do I need to use the Sigma Dock with my Sigma lens in addition to adjustment on the body? MAYBE. The best way to find out is to try. If you can achieve good result with adjustment on the body, no need to bother with USB dock. With a zoom lens, you will find that you have more flexibility with tuning the focus for different focal lengths and for different distances to the target using a Sigma Dock. 18. Final comments. Some vendors include USB dock in a package with Sigma lens. This way, one can get it at no or little added cost. It is beneficial to get a dock along with your compatible Sigma lens, then to find out that you need it as an after-fact. Tuning the focus with Sigma Dock does not void the warranty and is fully reversible. There is a button in the software to go back to factory defaults (which coincidentally are all zeros). Sigma Dock is also useful as it enables you to update lens firmware whenever a new version of firmware becomes available. You need only one dock for all of your dock-compatible Sigma lenses.

## Features

- Customize: Autofocus, OS, Focus
- Compatible with Global Vision Lenses
- Sigma Optimization Pro software in order to connect a photographers lens to their personal computer to update firmware and other parameters such as focus, and for the Sports category
- Compatible Lenses 35mm F1.4 DG HSM, 17-70mm F2.8-4 DC MACRO OS HSM / 17-70mm F2.8-4 DC MACRO HSM, and 120-300mm F2.8 DG OS HSM
- The adjustment is processed with special software (SIGMA Optimization Pro).

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B00CBQ5YOS |
| Batteries | 1 12V batteries required. |
| Best Sellers Rank | #86 in Camera Lens Caps |
| Customer Reviews | 4.6 4.6 out of 5 stars (4,842) |
| Date First Available | April 12, 2013 |
| Is Discontinued By Manufacturer | No |
| Item Weight | 2.29 ounces |
| Item model number | 878954 |
| Manufacturer | Sigma Corporation of America |
| Product Dimensions | 4 x 2 x 2 inches |

## Product Details

- **Brand:** Sigma
- **Color:** Black
- **Compatible Devices:** Canon EF
- **Global Trade Identification Number:** 00085126878542
- **Hardware Interface:** USB
- **Item Weight:** 65 Grams
- **Number of Ports:** 1
- **Product Dimensions:** 4"L x 2"W x 2"H
- **Total USB Ports:** 1
- **Wattage:** 2.5 watts

## Images

![USB Dock for Canon - Image 1](https://m.media-amazon.com/images/I/71u1CdKAOzL.jpg)

## Available Options

This product comes in different **Style** options.

## Questions & Answers

**Q: So with just this dock and usb cable connected to computer, you can adjust the focus without doing anything else. Just from what you see on computer ?**
A: No you must first take a series of test shots, I use a target mounted vertically as a focus target then a ruler set at 45 degrees. For each of the the designated focal lengths 4 on my zoom, and for three different focusing distances. A total of 12 pictures. Then download and decide whether the lens focuses in front of or behind the target. Lastly you put the lens on the dock and adjust the focus slightly in the needed direction. Then repeat the process until you are happy with the focus. Although a pain,  it took me three hours, the focus is MUCH better now.

**Q: I have a Nikon D5300, and just purchased a Sigma 18-35mm 1.8 Lens, do i need really need this?**
A: The dock allows you to do software updates for the lens .  It also allows you to do micro adjustments to focus .   Some cameras allow this fine tuning adjustment, but only one adjustment per lens.  The dock allows you to adjust at different focal lengths, not just one. If you have no focus issues with the lens and camera , then you probably don't need the lens dock.

**Q: Will this work on a Sigma 30mm f/1.4 DC HSM Lens for Canon Digital SLR Cameras (Black)?**
A: Its the 35mm that works not the 30mm.

**Q: Do I need this for my canon 70d and sigma 18-35mm 1.8?**
A: Like anything, the need is up to you.  I have a dock for my Sigma Art lens, including the one you own.  The dock allows you from you home with an Internet connection and computer, to update your lens software, and to correct front and rear focusing issues.  Because Sigma is a third party lens company, making lens for several cameras, they don't always get the focusing right for every camera manufacturer.  All of my Sigma Art lens (3) needed some correction.  By the way, you have purchased the Best APSC (crop sensor) lens in the world!  My Sigma 18-35mm f1.8 takes the 'Best' pictures of any lens I own.  And, I own both crop sensor and full frame cameras and lens to match both.

## Customer Reviews

### ⭐⭐⭐⭐⭐ A brilliant idea by Sigma
*by J***Y on November 13, 2013*

This is equivalent to reviewing a movie. The details of the delivery media (say a DVD) is much less interesting than the movie itself. The hardware, in this case the USB Dock you're considering purchasing, just works as expected. You attach it to your supported lens and plug it in to your computer. Settings you make in the software is transferred to your lens. End of story. This review focuses on the entire solution, particularly the software - its design and how well it addresses the problem at hand. Top camera bodies from Nikon and Canon (and possibly others) support lens focus fine-tunning. Notice that, due to fabrication tolerances, this fine-tuning is necessary to match a particular lens to a particular camera body. I have tunned all my lenses and can attest that it does make noticeable difference in image quality. The problem is: You can only set one value per lens. Say your body/lens combination backfocuses. You set a negative value, essentially telling the camera to front focus a bit to compensate. That works well for a prime lens, but not for zooms. What if the zoom back focuses at the short end of the range but front focuses at the long end? Sigma had a brilliant idea: move the tuning process away from the constraints of the camera and into a computer where it can be done properly. Not only it allows fine-tuning the focus, it also allows one to customize a (supported) lens for different behaviors. In the case of my Sigma 120-300mm f/2.8 there are 2 variables, namely Autofocus={speed priority (fast, a bit jumpy), accuracy priority (smooth but slower), default (somewhere in between)} and Optical Stabilization (OS)={heavy, light}, for a total of 6 possible combinations. You'll need this dock and the accompanying software to set your preferred custom behavior into the lens. There is a third function: one can update the firmware in the lens using this dock. Firmware in a lens... that's a first for me. The fact that they had to put microprocessors in a lens to implement this in-lens customization (and thus needing firmware updates) should be transparent to the user. So I won't count this firmware update function as neither a pro nor a con. It must be noted that Sigma's solution surpasses the current state of the art (from Nikon/Canon/etc), in that you can set not only one but at least 4, and up to 16 values, depending on whether the lens is a prime or a zoom. The price for this much flexibility and control is the escalating amount of trial and error steps (set in computer, test on camera, repeat...). It's almost overwhelming and addictive. And I like it. The software (not supplied with the dock, but it's a free download) is well executed, with a simple and intuitive presentation. There are some defects here and there, mostly text that get truncated because they don't fit in a window panel that can't be resized. Fortunately, one can bring up the help and read the message in its entirety there. I'd say the software is so intuitive that there's really no need for help at all. Most of the text in the help is a copy of the text you see in the software anyways. It would've been nice if they elaborated/reworded what you see on the software panels. For example, when setting the OS customization, you can pick from Dynamic View Mode ("This mode offers a recognizable OS effect to the image in the viewfinder. This helps to ensure the composition of images quickly.") or Moderate View Mode ("This mode offers an excellent compensation of camera shake, and achieves very smooth transition of the image in the viewfinder. The composition of the image remains natural even when the angle of view keeps changing."). The explanation in the help is exactly the same as in the software. Can you tell which mode has more OS and which has less? I used the terms "heavy" and "light" above, which are more descriptive than "Dynamic" and "Moderate". If you want to know... Dynamic View=heavy and Moderate View=light. The one con that I can think of is this: while the software automatically recognizes which Sigma lens you docked, it has no knowledge of which camera you intend to use the lens on. The software stores only one setting for each lens. It would be nice if Sigma were to add the ability to memorize several settings for a particular lens (each corresponding to different cameras) so that they can be easily and quickly recalled and loaded into the lens. On the whole, I'd say this USB Dock is likely a must have item if you want to get the most out of your Sigma lens, especially a zoom lens (like the 120-300mm f/2.8). This is the best tutorial on how to use the Sigma Optimization Pro software that I know of. http://vimeo.com/64665246 Update 4/01/2014: Sigma has since introduced 7 new lenses (including the 3 for mirrorless cameras) and none of them support/use this dock. I don't know why they've chosen that route, but the end result is that, at this time the value proposition of this dock isn't what Sigma suggested it would be. I'm changing my review from 5 to 4 stars until I see more lenses compatible with this device. Update 9/14/2014: Per Sigma's website[...] all 8 (A, C, S) lenses support this dock. Only the mirrorless series of lenses don't support this dock (I don't know why that must be the case; it seems like it'd be a good idea for all lenses to be focus fine tune-able, mirrorless or not). They must have forgotten to update that site last time I checked, which led me to my conclusion in the previous update. Their site has been corrected now. I'm changing my rating back to 5 stars.

### ⭐⭐⭐⭐⭐ Worked well to tune sharpness Sigma 18-300 zoom lense: Now I am happy! Q&A for you
*by A***. on August 6, 2019*

This is a very useful tool for Sigma zoom lens, or for any Sigma lens if your DLSR does not have AF microadjustment. I will answer several questions which you probably are asking yourself: 1. Which one to get? "Sigma USB Dock for Canon" means a USB dock for Sigma lenses with Canon mount, i.e, lenses designed to work with Canon cameras. If you own a Canon camera, buy a Sigma USB dock for Canon. If you own a Nikon camera, buy a USB dock for Nikon. Do not forget that this dock only works with Sigma lenses, and only with selected Sigma lenses. 2. Does it work with all Sigma lenses? NO! It only only with most Contemporary, Sport and Art series lenses. Sigma web site has up-to-date list of compatible lenses. Search for for "Sigma USB Dock" on Sigma web site, or go to Sigmaphoto web site and navigate from Home to Accessories -> Lens Accessories -> Category: Miscellaneous -> Sigma USB Dock. There, you will find the list of about 26 lenses supported by the dock, a link to download the free software, and link to tutorials. Scroll all the way down to the bottom of that page, below the table with compatible lenses, to find the link to the manual. 3. Does not work with Nikon or Canon brand lenses? NO WAY! The dock is just the means for the Sigma software to talk to the electronics in the Sigma lenses. It only works with Sigma brand lenses, and only with selected ones, which have this capability. 4. What is lens autofocus (AF) adjustment? Most DSLRs, with the exception of mirrorless ones, have a separate sensor for autofocus. It is possible and happens quite often that due to tolerances in manufacturing of camera bodies (and lenses), the focus which appears to be perfect to the autofocus system turns out to be slightly out of focus on the image sensor. There are two way to adjust for it. High end DLSRs have a so called "AF micro adjustment" (the exact term for it depends on the DSLR brand). This adjustment in the camera itself can even be lens-specific, i.e., you can program your high end camera body with individual AF adjustments for each lens you own. Sigma went one step further, they included AF adjustment into software/firmware of their lenses and provided an option to use different adjustments for different focal lengths. This works great with long range zoom lenses, which may front-focus on low end of the zoom range and back focus on the high end, or the other way around. You get multiple adjustment points instead of a single one on a camera body. 5. What does this USB dock do? It enables you to update lens's firmware and to program autofocus correction factors into the lens. It is just an interface between your lens and your computer. Basically, it is a dummy plug which matches your camera brand's mount with contacts to connect to contacts of the lens and with a USB interface. 6. Is calibration done automatically? How long does it take? Unfortunately, it is a tedious manual work. The dock is just an interface between your computer and lens's firmware. You do all the work and then use the dock to upload updated parameters into the lens. The dock does not measure anything and does not calibrate anything on its own. You buy a focusing target, install the free Sigma software (free download from Sigma web site), connect your lens, write down the focal lengths and distances from the table provided in the software, then grab your camera, set it on tripod, set it to center point AF, single shot AF, center point metering, set up the camera at one of the four distances listed in the Sigma software (you cannot change those, they are given to you), and take picture of the focusing target for each of the zooms listed in the table (if applicable to your lens) and each of the distances. If it is a single focal length zoom, you will only take 4 images from different distances. If it is a zoom lens, you may have to take as many as 16 images, a matrix of four focal lengths and four distances from the target. Then, you download images from the camera and examine them closely on the computer screen. The AF target has a tilted scale (looks like a ruler) which enables you to make a judgement where the best focus is - is it right at the center, where the focusing plate is, or is it behind the area which you focused on, or in front of it, and by how much the center of the area which is in good focus is shifted relatively to "zero". It is fairly easy to see. Once you've done it, the next step is to enter some numbers into the table in Sigma software. The numbers are in focus units, not in cm or inches. They probably are just steps of the stepping motor in the lens. They do not directly correlate with distances and Sigma does not provide any guidance as to how to correlate what you see in the pictures with required changes to focus parameters. All you know that you should increase the focusing parameter in a positive direction, e.g., from 0 to 5 (the total range of adjustment is from -20 to +20) if your camera front-focuses and you want to move the focal plane further away from the camera, and reduce it (e.g., from 0 to -5) if your camera back-focuses and you need to bring the focal point closer to the camera. Basically, you end up doing bracketing through several iterations, first making large steps and then smaller steps to dial the focus in. With my lens (Sigma 18-300), a focus step was roughly matching 1/2 of a centimeter on the inclined ruler of the focusing target with shorter distances between the lens and the target, but this is a very rough guideline. If you see that focus is off center, change the parameter by 5 units in the proper direction and check in the next round of measurements if this was enough. If not, change again and take more pictures. If you went too far, take a smaller step back. Repeat until you are satisfied. In my case, with Sigma 18-30, it took about 5 hours for 6 iterations for my son and I to complete the task to a reasonable level of satisfaction. 7. How do I know that I need to calibrate my Sigma lens? The indications are: soft focus across the whole range, or on the high or low end of the zoom range. Images come with sharp areas not quite where you focused on, i.e., on something a little closer to you or a little further from you than the focal point. Also, if your camera has "live view" (which is focusing using image sensor instead of autofocus sensor), you can compare images taken in live view and in standard mode. If live view images are noticeably sharper, your AF requires tuning. 8. Where to find more information on how to do it? Sigma has a manual for the software (fairly lousy, I must say) and a tutorial video. I found videos posted by Digital Goja very helpful. Those can be found by Googling for "Dijital Goja Sigma USB dock video". Finally, an article which can be found by its title, "Lens Calibration Explained" (just copy this into Google) was very useful to me to understand what I was supposed to do and why. This article does not explain the Sigma USB dock (instead, it discusses adjustments of AF on the camera body), but is very helpful to understand the rest of the process and tools needed. 9. Do I need anything else, beyond the Dock? You need a DSLRKIT or any other lens focus calibration tool. You can get it from Amazon for $6 - $9, or even download drawings from the Internet and make a target from cardboard at zero cost. You need a tripod to mount your camera. You need a source of bright light to illuminate your target if you do it indoors (you can do it outside and use sunlight). You need a tape measure to measure distance from the target to the camera. Finally, for measurements with "Infinity" distance, you need to find something relatively small across the street, like a house number or something. With "Infinity", there is no inclined ruler on the focusing target to access where the focal point is, you go by sequential trial of several settings and comparison of images. 10. How do I deal with measurements at "Infinity"? I just took pictures at several values of parameters entered into Sigma sofware (like 0 , 5, and 10) and compared the pictures, to find the sharpest. You cannot use the target at Infinity (they are too small - of course you can make your own giant one!), and might struggle at 20 feet, too. Just take pictures of something with sharp contrast and small to medium features at several focus correction parameter values, compare them, and identify the best sharpness setting. 11. Is the process of calibration worth it? If you suspect that your lens is not a sharp as it should be, this USB dock will take your lens to the next level. The difference is between you being frustrated about your purchase and being happy. At least, this is how I felt before and after calibration. I changed from "I may have to return this lens, my cell phone shoots much sharper pictures" to "It works very well" within 5 hours. Some vendors sell USB Dock in package with Sigma lenses. 12. What is in the box? USB dock, a USB cable, warranty card, and some kind of manual which I did not even open. 13. How to set the camera for shooting test images? Very important! Single point (center) AF. Center point metering. Single shot AF. ISO set to a low value, e.g., 100 or 200 to reduce noise in the images (helps to see the sharpness level better). Shoot in Aperture priority mode with F-stop set to the lowest possible value allowed by the lens for a given focal length. 14. Which Sigma lenses benefit most from AF tuning? Long range zoom lenses (which may back-focus on one end of the zoom range and front-focuse on the other end) and very bright lenses with very low values of F stop, like 1.2 or 1.5, which have a very shallow depth of focus. 15. Do only Sigma lenses require tuning of autofocus? Apparently, no. Apparently, all lenses of all brands can benefit from it. All pro level cameras have a single-parameter AF tuning built into the DSLR bodies. Sigma is different in that it took one extra step forward and created a solution for tuning across the whole range of zoom. This increases the precision of tuning. No other manufacturer offers USB dock for lenses. Sigma dock does not work with any other brands of lenses. Not even with older Sigma lenses. It is a very new technology. 16. Do I need to have a Pro level Camera to feel the difference, or need to use a USB Dock? As I learned it hard way, it is just the other way around: if you have an entry or mid level camera (I bought Canon Rebel T7i) which does not have a micro adjustment of autofocus, tuning of the lens with USB dock is the only option, short of replacing the lens over and over again until you find the best match to your body. It is a combination of body and the lens that determines sharpness. The same lens may be perfectly sharp on DSLR body A and not sharp on DLSR body B. Go figure. 17. Is it just the lens that determines if focus needs be tuned? No, it is a combination of the lens and the body. The thing is, most DSLR (with the exception of mirrorless DSLRs, which never need focus tuning) have a separate sensor for autofocusing, with an additional mirror which redirects the light from the lens to the autofocus sensor instead of the image sensor. If the distance which light has to travel to the autofocus sensor is different than the distance to the image sensor, just by a tiny amount, the AF sensor will decide that the image is perfectly focused, but the image sensor will see a blurry image. Lens might also have manufacturing tolerances which could contribute to operation of autofocus. The end result depends on combination of individual parameters of lens and body. Lens A may be super sharp on body X but not on body Y. 18. If I have a micro-AF adjustment on my DSLR, do I need to use the Sigma Dock with my Sigma lens in addition to adjustment on the body? MAYBE. The best way to find out is to try. If you can achieve good result with adjustment on the body, no need to bother with USB dock. With a zoom lens, you will find that you have more flexibility with tuning the focus for different focal lengths and for different distances to the target using a Sigma Dock. 18. Final comments. Some vendors include USB dock in a package with Sigma lens. This way, one can get it at no or little added cost. It is beneficial to get a dock along with your compatible Sigma lens, then to find out that you need it as an after-fact. Tuning the focus with Sigma Dock does not void the warranty and is fully reversible. There is a button in the software to go back to factory defaults (which coincidentally are all zeros). Sigma Dock is also useful as it enables you to update lens firmware whenever a new version of firmware becomes available. You need only one dock for all of your dock-compatible Sigma lenses.

### ⭐⭐⭐⭐⭐ Review
*by T***. on March 27, 2025*

Funkar som förväntat 📷

## Frequently Bought Together

- Sigma USB Dock for Canon
- Sigma 150-600mm 5-6.3 Contemporary DG OS HSM Lens for Canon
- Altura Photo 95mm Lens Filter Kit - Multi-Coated UV Protector, CPL Polarizing and ND Neutral Density Filters + Case for Camera Accessories & Lenses

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*Last updated: 2026-03-19*