Did not really know where to place this one. Came across this. Apparently there are some issues AF with assist beams. Not really clear if it is the new 600EX-RT or the 5D3. It appears it is point to the 5D3. Before the sun came up I waked around in virtually dark rooms and took about 100 shots. Had a few delays more than a second but most of the time this combo worked well. The only real delay I had was using the outer focus point and shooting about 25 feet away.
Someone mentioned there is a little wiggle room in the hot shoe. On centre point focus you can see it when testing shooting a wall. If I twist the flash to the right the AF beam is centred. Move to the left it is off a not but I did not see any real difference in AF acquisition.
Not sure if this has been started in another thread. Anyone else experienced this? If it is the 5D2 then other flashes should effect it as well if this is actually happening.
The AF assist beam is only rated at half the distance, compared to the center, for the outer points. If you are using AF assist for the outer points at 25 feet, you are getting little or no assist (hence the AF delay). Also, anything wider than 28mm isn't covered by the pattern. The specs of the 600EX AF assist beam:
AF Assist Beam
System: Near-infrared light pattern projection method
Linkable AF Points: Supports 1 to 61-Point High Density Reticular AF
Supported focal length:
- EF Lens: 28mm or greater
- EF-S Lens: 18mm or greater
Effective Range (Approx.):
At Center: 2.0 - 32.8 ft. / 0.6 - 10 m
Periphery: 2.0 - 16.4 ft. / 0.6 - 5 m
All the Canon Speedlites I have owned were similar: dimmer beam towards the periphery and limited wide angle coverage.
I just checked your profile. Loved it . Thanks for the feedback.
I never really expected my gear to pick up an outer focus point at that distance very quickly so I was not surprised. It aligns with the info in the manual. In that link I posted people saying under normal conditions the 5D2 was better or had much quicker acquisition. Not sure what to make of that. Not concerned but have not shot and event with it yet.
I am one of those who has used the 5d3 quite a bit (5 weddings in a month) and wasn't wowed by the AF performance at the reception. IMHO the 5d2 is NOT faster, but the 5d3 isn't stunning in that respect either. It did nail focus, and the outer points are indeed very reliable. Prefocusing does help , but under very dark reception conditions it doesn't live fully up to the hype. It does seem that the 5d3 gets close quickly and then takes a pause to lock in the last bit
No doubt, the 5d3 is an excellent camera and I love the ability to use more than 1 AF point - I would not trade back to a 5d2.
I also do weddings...I used the mark2 up til now and still use it alongside the mark3...using
600rt flashes with some off camera and of course one on camera....the mark2 is much
quicker to acquire focus with the flash assist at any distance...using the center point in
one shot mode...it is instant...where as you are waiting for the 3 to finally give confirmation...at least a second delay. The mark 3 works better in ai mode...but doesn't
always acheive reliable focus that way
Chuck Westfall on the old Rob Galbraith forums once explained in depth why the 5Dc would lock on faster with center point than the 1DsII. Basically the 1 series used another layer of calculations to recheck focus that the 5D didn't hence the speed difference, especially in tricky lighting. The 5D was faster at claiming that it had achieved focus but whether it had or not was not confirmed until you got back to the computer. The 1 series was slightly slower due to making sure but when it told you that it was in focus, you could really rely on it, whatever the lighting.
The 5D3 I was checking was slower, annoyingly slower, but heck if it didn't nail that focus perfectly in low light with every shot at f1.6 on the 50mm. My 5Dc can't do that. 2 out of 4 if I'm lucky.
Ouch! That's the first I have heard of such an issue with the 5D3. My 5D2 locks almost instantly in low light if I'm using AF assist from a Speedlite or ST-E2. It almost appears as if the 5D3 is treating low light AF as if AF assist is not being used. Also probably a FW fix is all is needed.
The AF issue with focus assist is the only issue with the camera IMO. It's sad and I hope canon look into it. It's been reported by enough people by now...
Zenon Char wrote:
This was was in interesting post by Beni
Chuck Westfall on the old Rob Galbraith forums once explained in depth why the 5Dc would lock on faster with center point than the 1DsII. Basically the 1 series used another layer of calculations to recheck focus that the 5D didn't hence the speed difference, especially in tricky lighting. The 5D was faster at claiming that it had achieved focus but whether it had or not was not confirmed until you got back to the computer. The 1 series was slightly slower due to making sure but when it told you that it was in focus, you could really rely on it, whatever the lighting.
The 5D3 I was checking was slower, annoyingly slower, but heck if it didn't nail that focus perfectly in low light with every shot at f1.6 on the 50mm. My 5Dc can't do that. 2 out of 4 if I'm lucky. ...Show more →
Since writing that I've decided to hold off on the 5D3 till this is sorted out, I've read a bunch about this including that thread on the canon forum and having seen for myself how much slower the focus was in low light even without flash, I'm holding off. Yes it can do the wide open more accurately but when I'm shooting weddings I need it to be fast when I'm using f2.8 and flash and the 5D3 can't do it as fast as my 5Dc which can and does it accurately each time too at those apertures.
Gochugogi wrote:
Ouch! That's the first I have heard of such an issue with the 5D3. My 5D2 locks almost instantly in low light if I'm using AF assist from a Speedlite or ST-E2. It almost appears as if the 5D3 is treating low light AF as if AF assist is not being used. Also probably a FW fix is all is needed.
We can only pray it is a FW fix. Other than that it would be a recall which I doubt will happen.
I did a quick peek around the 'net and apparently all EOS cameras, even older models, focus really slow with the 600EX Speedlite AF assist enabled. So it may be more than a 5D3 issue.
Gochugogi wrote:
I did a quick peek around the 'net and apparently all EOS cameras, even older models, focus really slow with the 600EX Speedlite AF assist enabled. So it may be more than a 5D3 issue.
It's the same with the 580EXII. It's definitely not the flash...
I have a theory that, with the focus assist, it's expecting the focus to be SO bang on that it takes a while to achieve it.
. Thanks for the feedback.