topic Re: Focus adjusting R6 Mark II with Sigma lens in EOS DSLR & Mirrorless Cameras

Focus adjusting R6 Mark II with Sigma lens

Milan1 — Sat, 08 Mar 2025 16:59:58 GMT

Hello, so i bought my r6 mark ii and i bought a sigma lens the 24-70 art.And the focus is just missing,it is giving me pictures like shooting on a slow shutter while shooting on a >1/1000 shutter speed and wanted to ask can i calibrate it from home or i need to go to a service because am very far away from every service for the sigma lens?

Re: Focus adjusting R6 Mark II with Sigma lens

deebatman316 — Sat, 08 Mar 2025 17:07:31 GMT

Mirrorless cameras cannot front or back focus so there is no AFMA (Autofocus Micro Adjustment)/ AF Fine Tune. Also what is the Full Name of your Sigma lens. What mode is the camera's top mode dial set to also what is your ambient lighting like. What is the shutter speed the camera is setting 1/1000th is a fast shutter speed. Also what mount adapter are you using the Canon brand mount adapter or a 3rd Party mount adapter. 3rd Party Mount adapters are nothing but trouble and cause all sorts of problems. Such as the camera locking up, no communication with the lens etc.

Re: Focus adjusting R6 Mark II with Sigma lens

Peter — Sat, 08 Mar 2025 17:24:16 GMT

You can use third-party software for R6 to adjust the AF (limited to 7 lenses), but it may take a year before R6 II is supported.

Re: Focus adjusting R6 Mark II with Sigma lens

Milan1 — Sat, 08 Mar 2025 17:59:26 GMT

I am using the canon adapter,I am shooting manual.It is the Sigma Art 24-70mm DG OS HSM EF mount the photos are not sharp when i zoom in to 70mm it is giving me shaky vibes like it is shooting on a slower shutter like 1/40 or 1/30 I can post a picture so you can see it or make you a link from the photos that i took.I think the problem is within the lens some update or some calibration and if you know how to it manually from home i will be pleased.Thank you for your response.

Re: Focus adjusting R6 Mark II with Sigma lens

deebatman316 — Sat, 08 Mar 2025 18:06:30 GMT

Does that lens have IS are you setting your shutter to a slow one. If so the picture would have camera shake then. If this lens has IS turn it off and see if the problem persists. A lot of older Sigma often times plays "IS tug of war" with the AF system and also with cameras with IBIS. Does the image shake in the viewfinder or rear LCD screen. Some Sigma lenses support's Sigma's dock for updating the firmware. But a lot of older lenses do not support the dock in this case the lens would have to be sent to Sigma. Have you tried a Canon lens to see if it continues to happen. Also post a picture in the forum so forum users can better assist you.

Re: Focus adjusting R6 Mark II with Sigma lens

Milan1 — Sat, 08 Mar 2025 18:13:46 GMT

yes I have tried with and without the OS on the lens and the shutter speed was faster than 1/1000 of a second and before the sigma i was using the RF 50mm 1.8 it was working perfectly I can buy a dock but i dont know if it is going to work so i dont want to spend more money on a gear that doesn't work properly.

Re: Focus adjusting R6 Mark II with Sigma lens

deebatman316 — Sat, 08 Mar 2025 18:22:04 GMT

Can you post a picture in the forum to show how the pictures come out.

Re: Focus adjusting R6 Mark II with Sigma lens

March411 — Sat, 08 Mar 2025 19:46:16 GMT

Milan, if you like the lens pick up a Sigma USB Dock for Canon EF-Mount lenses and download the dock required SIGMA Optimization Pro software. The dock will allow you to update the lens firmware but more importantly it also allow you to adjust focus position, AF parameters, OS settings, etc. (select lenses). Customize rotation sensitivity of focus ring in MF mode (select lenses).

The instructions for how to use the dock and software are terrible but there are some outstanding videos on youtube to assist you.This video shoot to the 5:30 mark for lens calibration.

Re: Focus adjusting R6 Mark II with Sigma lens

Milan1 — Sat, 08 Mar 2025 22:44:28 GMT

Thank you so much for your time so i don't need to attach anything to my camera its just the dock and the lens thank you !!

Re: Focus adjusting R6 Mark II with Sigma lens

March411 — Sat, 08 Mar 2025 22:50:40 GMT

Yes, you can pick them used for $20 or new for about $45. Watch the video, there is a process to follow to obtain improved focus.

Re: Focus adjusting R6 Mark II with Sigma lens

abhinavvdas — Mon, 09 Mar 2026 15:58:01 GMT

Hi Milan,

I have exactly the same setup and facing the same issue. Were you able to resolve it?

Re: Focus adjusting R6 Mark II with Sigma lens

March411 — Mon, 09 Mar 2026 18:48:11 GMT

Our pleasure @Milan1 we are here to help.

Re: Focus adjusting R6 Mark II with Sigma lens

WojtekZag — Fri, 05 Jun 2026 12:26:27 GMT

I'm afraid that reverse-engineered lenses won't work well with the new Dual Pixel CMOS AF II system. I have the same problem with the R6mk2. It's a Sigma 70-200 Sport lens. It works flawlessly with the Canon R6, but unfortunately not with the R6mk2... This is what I've managed to determine, but it didn't help:

1. Update the lens firmware (Critical) Older Sigma Art lens firmware exhibits communication errors with the advanced AF system in the Canon R6 Mark II (e.g., focus drift, random misses). Solution: You need to update the lens firmware to the latest version using the Sigma USB Dock and SIGMA Optimization Pro. This update adapts the lens algorithms to the tracking and subject detection algorithms in mirrorless cameras.

2. Disable aberration correction in the camera. Processors in newer Canon cameras (including the R6 MK2) attempt to automatically correct optical aberrations in system lenses. In the case of third-party lenses (Sigma, Tamron), these features often cause software errors and autofocus "stupidity." Solution: Go to the camera menu (red shooting tab) > Lens aberration correction > Disable all options (Peripheral Illumination Correction, Distortion Correction, Digital Lens Optimizer).

3. Verify Object Detection Modes. The Canon R6 MK2 has an extremely sensitive eye/face/vehicle detection system. If you're aiming at a subject and the camera is set to the wrong detection category (e.g., looking for animals when photographing people), focus may drift to the background. Solution: For testing purposes, disable subject detection and switch the AF area to Spot AF or 1-point AF. Check whether the lens is hitting the target point when aiming statically.
4. Check the stabilization (OS) function. In Sigma Art lenses, a faulty optical stabilization (OS) can cause the lens to jerk when the shutter is released, resulting in a completely blurry photo, simulating a focus outage. Solution: Disable the stabilization on the lens barrel (OS OFF), place the camera on a stable surface, and take a photo with a shutter speed of, say, 1/500 s. If the photos are sharp, the problem is a faulty OS module in the lens.

5. Burst mode and performance drop (so-called "Focus Pulsing")EF lenses designed for SLR cameras (including this Sigma) in SERVO continuous shooting mode on mirrorless cameras may not keep up with the work of the aperture and AF motor, which causes every second or third photo in the series to be out of focus. Solution: If the problem occurs only in the series, reduce the burst speed from the electronic shutter to the mechanical one ($12\text{ fps}$) or switch the mode to ONE SHOT (single AF) for static frames to check for clear optical sharpness.

Re: Focus adjusting R6 Mark II with Sigma lens

shadowsports — Fri, 05 Jun 2026 13:55:34 GMT

Greetings ,

@WojtekZag and @March411 great advice.

I owned this lens for over 5 and 1/2 years. Coupled with a USB dock to keep its firmware updated, it was one of the best lenses I've ever owned. Heavy and built like a tank but razor sharp photos 😍. I noticed a performance slowdown from a focus acquisition speed standpoint when I moved to mirrorless. My issue was primarily related to video, which was ultimately due to cinema OS on my R5 C. I didn't have problems with focus acquisition in photo mode. If you plan to keep the lens or you own more than one of sigma's global vision lenses (art, contemporary, sport) the dock is worth purchasing. I ultimately migrated to the RF 24-70. I purchased the EF version initially because it had IS. You may want to aspire to RF glass as the ultimate solution.