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5D3 + AF assist beam = slower focus


Hello All,


While I am new on these forums I have been on the Canon Rumors Forums for a few years now, 


I really wanted to bring this too the attention of you and Canon as it is simply a highly important problem, those of you that don't know, the 5D3 suffers serious focus locking issues when a Canon speedite is attached in Low light, the AF assist beam causes lag with the AF from the 5D3, this makes it virtually impossible to achieve focus in low light when the speedlite is attached, I wanted to bring the topic to this forum, so I have pasted a link to all the discussion we have already had about this problem at Canon - see below



Please help in letting Canon know this is a very serious problem and effects the cameras performance in most working environments when a speedlite is attached and working in low light, conferences, nightclub work, weddings etc, and can stop the photographer completing the job or task.




180 REPLIES 180

Hi steliosk! Since the 600D is not manufactured for use in the United States, Canon USA doesn't have any information on any issues it may encounter. If you're having issues with your specific product, and live outside of the United States, please click here and select your country or region for your support needs. We encourage you to discuss Canon products sold outside of the United States, but please be aware that you will not receive support directly from Canon USA.

Wow. They are really following these threads aren't they Man Happy

They are and its just so nice to hear it, Im really looking forward to the firmware, as I do love the 5D3,

First of all: aren't t3i and 600D the same product with the same firmware upgrades?
Second: i can't find a global canon forum to post my problem
Third: is Canon Europe a different company than Canon USA? i understand the support load, i can't find a support forum in Canon global so i chose you!

600D 60D and kiss x5 (which is the japan version) BOTH tested in a dark room with ex 580 and 24-105, BOTH face the same problem (both have the same firmware and settings)
Those cameras suffer from focus lag with the AF beam enabled, where in cameras such as 450D 350D 40D WHICH i've tested ALSO with the same settings (even the custom functions where matched) DOESN'T face this problem and the camera focuses instantly with the AF beam..

I've made a post here but i got ignored

Now you can run your own tests to see i'm telling the truth it won't take more than 2 minutes to find out, or you can insist on that bureucractic crap which will make me very displeased about canons policies, service and products.

Thank you

Hi everyone,

We have an update on this topic. A firmware update for the EOS 5D Mark III has just been released.  Firmware Update Ver. 1.2.1 incorporates functional improvements and fixes including uncompressed HDMI output, Center AF point to auto-focus at f/8 when used with Canon EF lens/extender, and AF speed improvement when using the Speedlite’s AF-assist beam.

To learn more and download the update, click here .

Thank you very much to everyone at Canon for this, there is no mention on the website that this firmware incorparates the assist beam fix?, but Im assuming it does, I will install it later, would like to hear what others have to say, 


Just a big thanks to everyone at Canon for listening to the Forums and helping us make this camera even more perfect,


all the best 


Louis Amore

Thank you again Canon


Here is the list


A list of improvements in firmware version 1.2.1 is listed below.

  1. Uncompressed HDMI output is now enabled.
  2. Enables the center AF point to autofocus when the camera is used with Canon EF lens/extender combinations whose combined maximum aperture is f/8.
  3. Improves the speed of the camera’s acquisition of focus when using a Canon Speedlite’s AF-assist beam.
  4. Fixes a phenomenon in which the LCD monitor may freeze and display Err 70 or Err 80 when a still photo is taken during Live View or in movie shooting mode.
  5. Fixes a phenomenon that may occur when the continuous shooting priority setting is enabled for multiple exposures, such that, after the sixth image is taken, there is a slight pause before the remainder of the sequence is completed.
  6. Fixes a phenomenon in which the viewfinder display shows incorrect information during AEB shooting.
  7. Communication with the WFT-E7 Wireless File Transmitter has been improved.
  8. When images have been successfully transferred with the WFT-E7 Wireless File Transmitter through the FTP protocol, an “O” will be displayed. When images have not been successfully transferred with the WFT-E7 Wireless File Transmitter through the FTP protocol, an “X” will be displayed.
  9. Fixes a phenomenon in which the camera may not function properly when an Eye-Fi card is used.
  10. Fixes a phenomenon in which the focal length value listed in the Exif information is not displayed correctly for images shot with the EF 24-70mm F4L IS USM lens.
  11. Fixes a phenomenon in which the lens firmware cannot be updated properly.
  12. Corrects errors in the Arabic language menu.
  13. Fixes a phenomenon in which the camera changes the AF microadjustment value to -8.
  14. Fixes a phenomenon in which the on-screen guidance cannot be fully displayed when setting the maximum limit value for the “Setting the ISO Speed Range for Auto ISO” option.

15. Eliminates competition from 3rd party battery makers by cutting communication between non-Canon batteries and the camera's battery meter. Please be good to the environment and take your non-Canon batteries to a battery disposal facility and do not put them in with your residential trash collection.

Canon 5d mk 4, Canon 6D, EF 70-200mm L f/2.8 IS mk2; EF 16-35 f/2.8 L mk. III; Sigma 35mm f/1.4 "Art" EF 100mm f/2.8L Macro; EF 85mm f/1.8; EF 1.4x extender mk. 3; EF 24-105 f/4 L; EF-S 17-55mm f/2.8 IS; 3x Phottix Mitros+ speedlites

Why do so many people say "FER-tographer"? Do they take "fertographs"?

Anyone install this update yet? Really want to know how the flash beam focus works now

Hi everyone,

Just to be clear, the firmware update does include an improvement to the AF speed when using the Speedlite’s AF-assist beam.  You can see the complete list of improvements and fixes in our product advisory by clicking here

Thank you Carerra911 for clarifying!

click here to view the gallery