5D3 & 600ex-rt + AF assist beam = slower focus

[verysimplejason]

I hope 5D mark IV or 6D mark II will combine the best features of 6D and 5D3.   

[digital paradise]

I have yet to test this in the real world but will be getting a chance soon. I was very happy with my 5D2 but wanted the pro AF the 5D3 offered. If I run into this there won't be a 5D4 in my future.

[Marsu42]

Time to dial back and concentrate on taking pictures again, not on spending money and talking about it.  Know what I mean?

Absolutely, esp. since a camera body the item to loose value fastest. But since I'm hoping to get some money out of this sooner or later, I'm even more pressed to get alleged "pro" equipment though I start to realize that for 90% of the shots the photog/postprocessing really makes the difference save some specialized settings like sports where precise tracking is most important. And I've come to evaluate non-"core" equipment (i.e. next to body+lenses) as more important, and that has also to be paid.

I think a major issue is this has been basically ignored at both DPreview and Fred Miranda. DPreview has surprised me as they usually latch on to these things like a Pit Bull.

My only explanation is that for the bug to show some less likely circumstances have to meet, like maybe some lens/distance/ambient light combinations while many other people maybe either shoot in good light (no af assist neeeded) or in pitch black darkness (af assist seems to work)? Not everyone shoots weddings or low light events...

[RustyTheGeek]

That's a good point Marsu42.  Using a DSLR as a non-pro in a party or wedding setting is rare.  It draws a lot of attention and even most pros don't feel like lugging a big DSLR when socializing or attending most functions where the light is in the range that is most conducive to the AF problem.  It's awkward to say the least.  So the problem goes either undiscovered or misunderstood.  IMO, it's wedding photographers, ironically the market segment Canon supposedly designed this camera for most of all, who will experience the problem the most.  All I can say is good luck!  If I primarily shot weddings, the 6D would be my main body or at least be a second body hanging to the side for the reception.  If I shot sports, then the 5D3 or many other bodies would be the way to go.  For me, the whole point of buying the 5D3 after waiting so long and skipping the 5D2 was to have a superior body to do it all and then some.  I still don't feel like I quite got that or I wouldn't have even considered, much less purchased, the 6D.  And unfortunately, the 6D fps is a bit slow for sports.  Maybe Magic Lantern will release a firmware that gives back the higher fps.  Oh well, time to go get some work done...

[Marsu42]

Maybe Magic Lantern will release a firmware that gives back the higher fps.

Very unlikely, Canon has surely designed the camera so that the hard specs cannot be easily circumvented - and the 6d port of ml has still trouble with the memory design of the 6d, so let's wait and see how it turns out at all. But I guess the 6d *could* do more fps, maybe Canon does a fw update in 2016 like recently on the 7d :->

[digital paradise]

Post # 115 from Canon Forums.

http://forums.usa.canon.com/t5/EOS/5D3-AF-assist-beam-slower-focus/td-p/2277/page/12

[AudioGlenn]

So I've been doing some further testing.  I can create a situation on my mk3 and 600 ex-rt where I can notice a much less snappy AF lock.  I was not able to re-create the lag when trying to focus in a very dark (almost black) setting.  Maybe, that's where I messed up in my prior testing.  Maybe a completely black environment creates enough contrast between the environment and the red focus assist beam to allow focus whereas a dimly lit situation is lit just enough to give the camera trouble focusing because it can't really see the red AF assist beam as well.

I'm able to notice a significant lag when the ambient light is dim (proper exposure in camera at f/2.8, 1/50, ISO 5000). 

Seems to me like I would just turn the beam OFF when I notice the ambient light is about at this level.  Am I still over simplifying the issue?  I get that pros need their focus to be snappy to catch those moments.  Wouldn't that mean a few test shots in the environment first to gauge the settings required....including wether or not to turn the AF assist beam on/off?

Maybe I don't understand the depth of the issue because I'm not coming from a 5D mk2 where the focus is supposed to be faster.  That said, I'm an engineer by trade.  We are trouble shooters by nature.  It seems like there's a pretty easy fix for this (just based off of what I've been able to test).  If this really is an issue for a shooter,  just turn the beam off when you feel like it's slowing you down.  Does ambient light in a reception hall or your venues change constantly for you guys?  Isn't this just a matter of your experience telling you how your camera should be set to capture moments?  I'm not trying to be condescending.  promise.   I still don't understand what the big deal is. 

[Marsu42]

I'm able to notice a significant lag when the ambient light is dim (proper exposure in camera at f/2.8, 1/50, ISO 5000). 

Doh, this is probably just the lv range for dark receptions and so on where the 5d3 should excel?

I still don't understand what the big deal is.

If the problematic range is easy to identify maybe a workaround is feasible if there is enough time, but is sounds like it's not the lv range but also the focusing distance and the lens model used. Next to that, the af assist on a €3000 camera should probably just work.

[jaayres20]

So I've been doing some further testing.  I can create a situation on my mk3 and 600 ex-rt where I can notice a much less snappy AF lock.  I was not able to re-create the lag when trying to focus in a very dark (almost black) setting.  Maybe, that's where I messed up in my prior testing.  Maybe a completely black environment creates enough contrast between the environment and the red focus assist beam to allow focus whereas a dimly lit situation is lit just enough to give the camera trouble focusing because it can't really see the red AF assist beam as well.

I'm able to notice a significant lag when the ambient light is dim (proper exposure in camera at f/2.8, 1/50, ISO 5000). 

Seems to me like I would just turn the beam OFF when I notice the ambient light is about at this level.  Am I still over simplifying the issue?  I get that pros need their focus to be snappy to catch those moments.  Wouldn't that mean a few test shots in the environment first to gauge the settings required....including wether or not to turn the AF assist beam on/off?

Maybe I don't understand the depth of the issue because I'm not coming from a 5D mk2 where the focus is supposed to be faster.  That said, I'm an engineer by trade.  We are trouble shooters by nature.  It seems like there's a pretty easy fix for this (just based off of what I've been able to test).  If this really is an issue for a shooter,  just turn the beam off when you feel like it's slowing you down.  Does ambient light in a reception hall or your venues change constantly for you guys?  Isn't this just a matter of your experience telling you how your camera should be set to capture moments?  I'm not trying to be condescending.  promise.   I still don't understand what the big deal is.

You are right the issue is occurs in very dim but not supper dark situations.  I shoot wedding receptions all of the time and the lighting changes constantly.  It happens during grand entrances and first dances all of the time.  You get set up for certain light and all of the sudden lights go off completely.  I always ask in advance to try to plan for those instances but they often happen without warning.  Different parts of a reception hall are also lit differently or facing different ways.  For example shooting with or against the DJ's lights.  I switch it on and off all of the time and have it registered on my menue settings so I can get to it quickly.  The problem is it still takes 5-10 seconds to do that and there are times you can't waste that time.  The bride and groom in a grand entrance and you loose 5-10 seconds and you may miss everything or most of it.  It is a pain to have to switch it on and off and I can't figure out why I need to.  If Canon gave me a reason then I could live with it but they don't even acknowledge there is a problem. 

[Marsu42]

You are right the issue is occurs in very dim but not supper dark situations.

Maybe that's really the reason Canon screwed up and still cannot reproduce the problem - they see af assist as a tool for shooting in pitch black conditions as the 5d3 af should be able to copy with just "low light" on its own? And probably the focus lag in dim light wasn't seen as a problem since the condition was considered to be unlikely.

However looking at the problems pro photogs have indicates the 5d3 testing with the new 600rt flash that was *made* to work with the 5d3 af spread was not good enough...

[dlleno]

I'm able to notice a significant lag when the ambient light is dim (proper exposure in camera at f/2.8, 1/50, ISO 5000). 

Doh, this is probably just the lv range for dark receptions and so on where the 5d3 should excel?

moreover, this is several stops above the minimum AF sensitivity in the published specifications.  are you guys depending on all AF or just the cross type points?  is there something about the subject (the white dress perhaps) that the sensor is tripping over?  obviously it can't be the lack of light...

[AudioGlenn]

Next to that, the af assist on a €3000 camera should probably just work.

point taken... you're absolutely right on that one.  Big deal indeed.  =)

On a side note, I'm going to the NAMM convention this week.  I'll be testing more there with and without AF assist beam.  I am actually very concerned about this issue.  I don't want to find out I can't do something in the middle of an important shoot, hence all the testing beforehand on my end.  I'll continue to post any new findings if I come across more data/ideas that will make our jobs easier.

Thanks to all who are contributing to the discussion here

[zim]

Maybe that's really the reason Canon screwed up and still cannot reproduce the problem - they see af assist as a tool for shooting in pitch black conditions as the 5d3 af should be able to copy with just "low light" on its own? And probably the focus lag in dim light wasn't seen as a problem since the condition was considered to be unlikely.

This sounds like a very plausible explanation to me, could even be described as a feature, but then why is it taking Canon so long to just say so?

[dlleno]

just from reading the interactions over on the Canon site, I can only suggest that they know about the problem but still studying the details and forming their response, i.e. will they ignore, will they fix silently, etc. 

just my opinion, based on the Canon response so far, is that they are in "keep their attention but delay until we figure out what to say" mode.  Three different Canon reps have dropped in once, only to say "we're here".  Perhaps the strongest point over there was to quote the Cannonusa.com description that 5D3 was ideal for weddings.   Hope that gets their attention. 

[RustyTheGeek]

I still contend (as I mentioned way back) that Canon knows more about the 5D3 than probably any other camera.  It's supposed to be their "big deal" camera designed for everyone and destined to follow the 5D2 in rocking the world of every pro and enthusiast that has a high credit limit.  They took their time developing and testing all the prototypes with pro beta testers in every situation.  I think they know and have known every strength and weakness of this camera since it was in early beta.  The fact that we are experiencing what they likely knew all along is somewhat meaningless to them and they probably plan to respond when they have something they think is considered progress on the problem and what we would like to hear.  In fact, if a firmware update can fix or improve the problem, the future April firmware date may be a deadline to keep the engineers engaged and motivated to fix the problem (among others).

Of course, this is all just an assumption on my part but I really have a hard time believing that Canon is so clueless about their own cameras that they need a user forum to explain the limits and flaws of something they designed, built and extensively tested (for years) themselves.