One Shot AF/AI Servo

[IanD]

I have read the manual a thousand times and don't think I missed this. Is there any way to set a Custom Function to switch from One Shot AF to AI Servo? I think you need a lens with an AI switch which neither the 100-4-- nor 70-200 have. Am I doomed to the AF button/thumbnail routine?

[Scottes]

You musta missed this on Page 65:

"The AI Focus AF mode switches automatically from One-Shot AF to AI Servo AF if the subject starts to move."

So leave it on AI Focus.

Of course, if it really was "AI" you would always take a picture of the front of the subject, so use this with care. :)

[CyberDyneSystems]

There is not quick way to switch,. you have to hit the microscopic button and spin one of two wheels,. make sure you use the correct wheel!

[IanD]

Scottes,
Read that a couple of times to let it sink in. My problem is (and I am probably doing this bassackwards) I use OneShot for "duck portraits" and if I see another duck flying over to join the party, I try to switch to AI Servo. Push button, spin wheel, miss shot.
What I really need is another 10D and keep one on OneShot and the other on AI Servo.
Yeah Baby! That is the answer.
Ring Ring Ring
<sound of wifes' divorce lawyer calling>
:lol: :lol: :lol:

CDS,
Pretty good at using the right wheel. I guess the ability to switch modes with a CF button would be on my list of "What I Want To Have On My Next New Canon"

Thanks guys.

[PacAce]

Scottes,
Read that a couple of times to let it sink in. My problem is (and I am probably doing this bassackwards) I use OneShot for "duck portraits" and if I see another duck flying over to join the party, I try to switch to AI Servo. Push button, spin wheel, miss shot.
What I really need is another 10D and keep one on OneShot and the other on AI Servo.
Yeah Baby! That is the answer.
Ring Ring Ring
<sound of wifes' divorce lawyer calling>
:lol: :lol: :lol:

CDS,
Pretty good at using the right wheel. I guess the ability to switch modes with a CF button would be on my list of "What I Want To Have On My Next New Canon"

Thanks guys.

Ian, if you want to shoot ducks or geese and want to be able to get them when they're static or when they're on the move, why not just leave the camera on AI-Servo mode? That's what I do whey I go after them critters. You're not going to lose anything by using AI-Servo except for the focus lock that ensures that you can't release the shutter before focus is achieved. But I don't think that that's going to be a big loss. So what if you took a couple of unfocued pictures? Just toss 'em out and don't tell anybody and nobody will be the wiser. :)

[Scottes]

My understanding of AI Focus is that if the subject is standing still - your duck portrait - it's in One Shot mode.

Now the other duck comes flying in. You focus on him, halfway-shutter, but he's moving. As you track him the camera detects that it's moving, and switches to AI Servo automatically.

Double-checking my "10D Short Course" book, that's still the impression I get.


I did read one post where the person said that AI Focus doesn't always switch over to AI Servo quick enough for him. (He was shooting small birds)

Then again, why not just leave it in AI Servo? As long as you're steady with your finger a stationary object won't be a challenge to ensure focus before depressing the shutter button completely.

[slejhamer]

why not just leave the camera on AI-Servo mode? ... You're not going to lose anything by using AI-Servo except for the focus lock

Picking up our conversation from another thread, you can use C.Fn-04-3 to get the benefit of AI Servo AND, if needed, achieve focus lock simply by letting go of the * button.

And in the context of what Scottes is saying, we could probably say that C.Fn-04-3 really gives you a manual version of AI Focus.

Both methods will work for what Ian is trying to do. One let's the camera do the thinking, the other requires thinking through your thumb (or whatever appendage you use to press the *. )

[PacAce]

Picking up our conversation from another thread, you can use C.Fn-04-3 to get the benefit of AI Servo AND, if needed, achieve focus lock simply by letting go of the * button.

And in the context of what Scottes is saying, we could probably say that C.Fn-04-3 really gives you a manual version of AI Focus.

Both methods will work for what Ian is trying to do. One let's the camera do the thinking, the other requires thinking through your thumb (or whatever appendage you use to press the *. )

Scottes,

Just wanted to add another point. My camer is set to AI-Focus most of the time specifically for the reason you site in your post. However, what I did find is that in AI-Focus mode, when you're trying to focus in on a moving subject, it take a little longer to get a lock, if it can manage that at all, and then track the subject. In AI-Servo mode, it seems to do that almost seemlessly as long as the AF point is over the subject. So, for birding sessions, I swith my camera from AI-Focus to AI-Servo if I anticipate getting birds-in-flight shots. If not, I'll just leave it on AI-Focus.

I used to use CF04 to set focus lock on the "*" button but my thumb was taking a real beating and hurting after long hours with the camera so I gave up on it. When I have my 100-400 lens on, my thumb still does hurt occasionally so I must be using the thumb to carry some of the weight of the camera and the lens. I should look into this to see why I'm doing that. Maybe I'm gripping the camera body to hard with my thumb. ???

[Ferdinand]

Do what Mitch said, CF4-3 and leave it on AI Servo, voila.

Also a quick question, do you guys set AF to center AF or all 7 point on?

Regards,
Ferdinand

[PacAce]

Do what Mitch said, CF4-3 and leave it on AI Servo, voila.

Also a quick question, do you guys set AF to center AF or all 7 point on?

Regards,
Ferdinand

I tried all 7 with AI-Servo just last week and I didn't get the results I used to get using a single center AF point so I'm going back to that. The problem with using all 7 was that the camera didn't know which one to use and a lot of times, the camera focused in on the wrong target. If the subject were large enough to fill most of the frame, 7 point would work great but otherwise it's best to tell the camera what to focus on.

[slejhamer]

Do what Mitch said, CF4-3 and leave it on AI Servo, voila.

Also a quick question, do you guys set AF to center AF or all 7 point on?

Regards,
Ferdinand

If I remember to do it ( ;) ), I will switch to all-7 AF points when using AI Servo. Keep in mind that focus tracking will begin with the center AF point, so that MUST be where you begin to track your subject. I have found the predictive AF tracking to work reasonably well if the subject moves to another AF point, though sometimes focus begins to hunt and I have to start over.

One advantage to using all 7 is that I can try to recompose by moving the subject away from the center AF point without losing focus. It's tough to do rule-of-thirds with the other points being where they are, but in my opinion off-center is still better than dead-on center.

All this talk about sport- and bird-shooting is getting me quite mad, because it is absolutely BEAUTIFUL outside right now and I'm stuck at my desk! Oh, to be at the pond ... :x

[Ferdinand]

Leo, I have the exact same problem. With all 7 point AF on, during a baseball game I was tracking the runners and the darn background was chosen instead of the players, so like you, I am going back to Center point AF then :) Thanks for your input.

Regards,
Ferdinand

[Johnnynf]

Ok, I may be really stupid, but I have read through this entire thread 5 times now, and a lot of it is like Greek to me. Some of it may be that you are all talking about the 10D (I have a DRebel)...but I think some is just that I have a lot to learn in this area. So, in "idiot" terms, what exactly is the difference between "One-Shot AF" and "AI Servo AF"? I think that AI Servo AF is used when trying to track moving subjects...am I correct? Am I also correct that on the DRebel, only the "sports mode" uses AI Servo AF...and does the "*" button simply lock in focus? I hope this isn't stooping too low for some of you, but the DRebel manual is kind of vague...and I shoot sports a lot, so I would like to learn more about what these two focus functions do.

Thanks!!

[IanD]

Thanks for the input guys. I had the chance to try the different setting this afternoon. Set up using AI-Servo produced great images. It is a little slower than AI-Servo though. I'm going to play around with C.FN-04-3 this weekend and see if I have the thumb for it. :lol:

[PacAce]

Ok, I may be really stupid, but I have read through this entire thread 5 times now, and a lot of it is like Greek to me. Some of it may be that you are all talking about the 10D (I have a DRebel)...but I think some is just that I have a lot to learn in this area. So, in "idiot" terms, what exactly is the difference between "One-Shot AF" and "AI Servo AF"? I think that AI Servo AF is used when trying to track moving subjects...am I correct? Am I also correct that on the DRebel, only the "sports mode" uses AI Servo AF...and does the "*" button simply lock in focus? I hope this isn't stooping too low for some of you, but the DRebel manual is kind of vague...and I shoot sports a lot, so I would like to learn more about what these two focus functions do.

Thanks!!

Yes you care correct re the AI Servo working in Sports mode. However, the "*" button cannot be used for locking focus on the DRebel because the DRebel does not have the ability to reassign this button via a custom function like the 10D does.

The discussion we were having on this thread was for the 10D although a lot wll also apply to te DRebel except the "*" button discussion.

[garethhhhh]

So, in "idiot" terms, what exactly is the difference between "One-Shot AF" and "AI Servo AF"?

One-Shot AF: When you press the shutter button halfway it obtains focus, pressing it fully will then take the picture regardless of whether the subject has moved / or is not in focus anymore.

AI-Servo AF: When you hold the the shutter button down halfway the camera will find focus and keep focus regardless of whether the subject is moving or not, until you let go of the shutter button

I think that AI Servo AF is used when trying to track moving subjects...am I correct?
Yes

Am I also correct that on the DRebel, only the "sports mode" uses AI Servo AF
Yes, the problem comes in when you want to use it in the creative zones. In the creative zones you can use something called called AI Focus instead, when AI Focus detects movement it switches to AI Servo automatically. However it doesn't work as simply as that, it has its problems. Click here (http://www.xmldatabases.org/WK/blog/1454_Digital_Rebel_Hack_No._2_-_Full_time_AI_Servo.item) to see how you can "fix" the problem.

...and does the "*" button simply lock in focus?
No, the Drebel does not have this functionality.

[Scottes]

Set up using AI-Servo produced great images. It is a little slower than AI-Servo though.


Huh?

[IanD]

Set up using AI-Servo produced great images. It is a little slower than AI-Servo though.


Huh?
Disregard the ramblings of a mad man. :lol:
Meant to say AI-Servo a little slower than One-Shot.
I knew what I meant. How come you didn't :?: :?: :lol: :lol: