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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

Louis, echelonphoto yes absolutely when buying a camera especially at this price point you need to test and prepare to return it if it does not meet its advertized capabilities.  in my view its important to purchase from a reputable and authhorized dealer and then when the camera arrives, you execute a very specific set of test cases to qualify the camera for your needs.  Its impractical to test every function, to be sure -- but indeed you should set aside a few days after receiving the camera to put it through its paces to see if it will provide the capabililty that is important to you and for which you spent the dollars to obtain.  


The 5D3 especially is a good example.  reports of bad low light AF performance, possible inconsistencies from copy to copy,  no meaningful response or help  from Canon (either here, the sales team or the service centers all of which are dreadfully silent on this topic) -- you bet your life the first thing out ot the box it should bet tested.  This is the kind of behavior that should put all perspective customers on alert -- Unfortunately, Canon has created the situation where one can no longer just buy a camera and trust.  you  have to test first ,and then decided if you want to keep it or your money.   

Unfortunately this situation has really turned me off to Canon and their quality control. I made the jump to the 5DMK3 and 600EX-RT as my first steps in "going pro" and getting serious about shooting weddings.


It's sad that I had an easier time with the AF of a T2i/7D with a 430EX2 and I will be stuck using my 7D for low light situations.


I just really wish Canon would address this as I feel like my 5D/600EX is a $4000 paper weight when shooting receptions.


On another note I am going to be performing some tests with both a 7D/5DMK3 and 430EX2/600EX-RT. I'm hoping I might find a combination that works and will allow me to use the 5D. So far I have seen the issue with both the 70-200f2.8 IS II and 16-35 f2.8 II. I believe the 50 prime had similar issues as well.

I am glad that I have held off to-date in purchasing the 5D MKIII,With the issues / results arising via various forums indicating serious flaws that have a considerable impact on the functionality of the equipment especially when being asked to part with £2300+ for the body alone.


As I only have the one EF does make me think about jumping ship to NIKON

EOS 5D MKIII + EF 24-105mm f/4L IS USM, Sigma DG 150-500 5-6.3 APO HSM, , EF 55-200mm 4.5-5.6 USM, Speedlite 430EXII

EOS 350D, EFS 18-55mm

Hi all, we are still listening to all of your valuable comments on this topic, and we expect to have an update for you shortly. Thanks again for your feedback on our forum.

Thank you Jessica.  Many folks on this forum (and others) appreciate you/Canon taking this issue seriously and working with us to address the problem.  Periodic assurances work wonders.

Yes let me add my thanks as well Jessica.. both prospective buyers and current owners are anxious for additional information

An optimistic reply. Thank you Jessica and thanks to everyone else who has voiced this issue on this forum and other forums.

Canon has a reputation for excellent support and I believe this will be resolved.

Thanks Canon.

To Jessica/Moderator, Naomi/Moderator, MIke/product expert, and any other Canon representitives that have participated /viewed  this forum or become appraised of its activity:


If I may presume to re-cap/summarize what is being said here, it is that the Canon 5D mark III  camera does not perform in the scenarios for which it is aggressively marketed, i.e.  with AF and extented ISO capabilities specifically designed  to "make the EOS 5D Mark III ideal for shooting weddings in the studio or out in the field"  [direct quote from]. 


Canon,  we want the 5D mark III to be succesful in these situations as advertised.  We want it to perform in the specific use cases described in this form (and elswhere), which include the fact that shooting weddings and events  "in the field" means photographic scenarios which demand fast AF performance to capture once-in-a-lifetime moments in churches and other dimly lit venues.  The forums here and elswhere have chronicled examples where professionals have deliberately avoided  the use of the Canon 5D mark III camera body in these scenarios because its AF system is too slow and cannot be trusted to deliver results.  The use cases of interest include using the camera both with and without the AF assist beam provided by genuine Canon accessories. 


FYI I am writing as a semi-professional,  carefully weighing the information as a prospective buyer looking upgrade my present capablity.  Thank-you for listening.

Thanks for pointing out the quote about being ideal for weddings.  

click here to view the press release