AI-Focus on 5D3

At some point (during 30D time frame) I had learned that AI-focus is bad. Never use it. Use AI-Servo only.
However I see posts where people are using AI-focus on their 5D3..
Has Canon improved it over these years and would that have the specific advantages (as it is mix of single shot and AI-Servo)?

Use single shot, or AI servo. Set it to the one best suited to your conditions.

AI focus is a terrible idea, but you seem to already grasp this, even if you are questioning yourself. Don't!

AI Focus is essentially letting the camera decide if you should be set to single or AI servo,. so yes, it's a mix, but it never gets it right!

This is just one of many options that should always be decided by the photographer, and not the camera.

CyberDyneSystems wrote in post #16014899
Use single shot, or AI servo. Set it to the one best suited to your conditions.

AI focus is a terrible idea, but you seem to already grasp this, even if you are questioning yourself. Don't!

AI Focus is essentially letting the camera decide if you should be set to single or AI servo,. so yes, it's a mix, but it never gets it right!

This is just one of many options that should always be decided by the photographer, and not the camera.

^^^^^^^^^
This

if it moves A1 servo
Portraits One shot

thats all you need to know with a 5D3

ditto

I wish AI focus could be relied on. I haven't really tried it because I'd heard similar things to the comments above, but children go from still to charging around with very little notice so I'm forever switching between one shot and AI servo.

I leave my camera in servo by default though, since if there isn't enough time to switch I figure there's more chance of a good result with servo and a still subject than one shot and a moving subject!

Thank you all of you... My "education" stays..

Savethemoment wrote in post #16015299
I wish AI focus could be relied on. I haven't really tried it because I'd heard similar things to the comments above, but children go from still to charging around with very little notice so I'm forever switching between one shot and AI servo.

I leave my camera in servo by default though, since if there isn't enough time to switch I figure there's more chance of a good result with servo and a still subject than one shot and a moving subject!

With Servo and BBF you can achieve the result that you are after manually.

AI focus for me 90% of the time unless im on tripod with non-moving subject.
been using this since 40D for me.

rrblint wrote in post #16015523
With Servo and BBF you can achieve the result that you are after manually.

Thanks. I do use BBF and find it much better than focusing with the shutter button, but my understanding is that servo mode isn't designed for still subjects so may not give good results with them. I haven't been scientific enough in assessing my servo vs one-shot photos with still subjects to see this for myself though. In fact just looking at the EXIF data showing in Lightroom it doesn't seem to indicate which focusing mode was used - I wonder if there's a way to find out? I may be missing something about what you're saying, if so please let me know!

I've also set the DOF preview button to switch between servo and one-shot, but my hands aren't large and it's a bit too far away to reach easily while controlling the other buttons so this turns out not to be very practical for me.

Savethemoment wrote in post #16015299
I wish AI focus could be relied on. I haven't really tried it because I'd heard similar things to the comments above, but children go from still to charging around with very little notice so I'm forever switching between one shot and AI servo.

I leave my camera in servo by default though, since if there isn't enough time to switch I figure there's more chance of a good result with servo and a still subject than one shot and a moving subject!

On 5dmk3 I used AI servo most of the time when shooting my kid pictures and it worked real nice even at f1.4 using outer points.

CyberDyneSystems wrote in post #16014899
Use single shot, or AI servo. Set it to the one best suited to your conditions.

AI focus is a terrible idea, but you seem to already grasp this, even if you are questioning yourself. Don't!

AI Focus is essentially letting the camera decide if you should be set to single or AI servo,. so yes, it's a mix, but it never gets it right!

This is just one of many options that should always be decided by the photographer, and not the camera.

Amen to that. I've never understood why Canon continues to offer this focus mode on their prosumer cameras. I guess I can understand it on the entry-level Rebels, because people simply don't understand the focus modes and refuse to read the manual, but by the time you've let the camera decide "oops, it's moving, better use AI-Servo mode" the moment is already gone.

bobbyz wrote in post #16015641
On 5dmk3 I used AI servo most of the time when shooting my kid pictures and it worked real nice even at f1.4 using outer points.

That's good! Was this even when they were standing/sitting still?

Savethemoment wrote in post #16015299
I wish AI focus could be relied on. I haven't really tried it because I'd heard similar things to the comments above, but children go from still to charging around with very little notice so I'm forever switching between one shot and AI servo.

I leave my camera in servo by default though, since if there isn't enough time to switch I figure there's more chance of a good result with servo and a still subject than one shot and a moving subject!

Thing is, AI-Servo works for non-moving subjects as well, despite what some people believe. The real difference is that in One-Shot the camera simply won't fire until it has focus lock, so it's kinda idiot-proof in getting in-focus images, but in AI-Servo it fires when you press the button, period.

Savethemoment wrote in post #16015635
Thanks. I do use BBF and find it much better than focusing with the shutter button, but my understanding is that servo mode isn't designed for still subjects so may not give good results with them. I haven't been scientific enough in assessing my servo vs one-shot photos with still subjects to see this for myself though. In fact just looking at the EXIF data showing in Lightroom it doesn't seem to indicate which focusing mode was used - I wonder if there's a way to find out? I may be missing something about what you're saying, if so please let me know!

I've also set the DOF preview button to switch between servo and one-shot, but my hands aren't large and it's a bit too far away to reach easily while controlling the other buttons so this turns out not to be very practical for me.

I'm not sure what EXIF Lightroom reveals but DPP will tell you what focus mode was used.

Using Servo with BBF and the "press and release" technique works great for still subjects in good light.

DennisW1 wrote in post #16015680
Thing is, AI-Servo works for non-moving subjects as well, despite what some people believe. The real difference is that in One-Shot the camera simply won't fire until it has focus lock, so it's kinda idiot-proof in getting in-focus images, but in AI-Servo it fires when you press the button, period.

Thanks, that's good to know. I do end up with OOF images

Edit - just realised that my original comment didn't make sense in light of your advice!! I'm going to do some more practicing/testing and examine the results. I might also not be using the best servo option for fast-moving kids & need to explore these.