How do you disable AI Servo?

Further tests have decisively shown (on my camera firmware) that if while having the shutter half pressed, you touch the front knurled focus ring on the lens, it will start to seek focus regardless of the lock and act as if it's unlocked. It only needs the lightest of touches - you don't have to turn it.

Touching the zoom ring doesn't have that effect.

The auto focus apparently detects that it has been moved off its held setting and attempts to correct that - which then negates the half-press.

--
Paul Worden

--
Paul Worden
 
So does this cause another focus lock or kick the camera into AI Servo? I guess I could try it but since you know already.... :-)
Further tests have decisively shown (on my camera firmware) that if
while having the shutter half pressed, you touch the front knurled
focus ring on the lens, it will start to seek focus regardless of
the lock and act as if it's unlocked. It only needs the lightest of
touches - you don't have to turn it.

Touching the zoom ring doesn't have that effect.

The auto focus apparently detects that it has been moved off its
held setting and attempts to correct that - which then negates the
half-press.

--
Paul Worden

--
Paul Worden
 
After you achieve focus lock, you can also kick the camera into AI Servo if you point it at something and its distance from the camera is changing, like if you start walking towards it.

Of course, you would never walk around to recompose. My point is that even if you have a focus lock, the camera is still reevaluating the contrast at the focus point. If it sees a gradual change in contrast anytime during the half-press, it will kick it into AI Servo.

This becomes a problem if, while recomposing after a focus lock (holding still until the beep and dot and everything), you pan the focus point over a surface that is slanted away from you. The camera perceives a gradual change in contrast (distance), and it kicks into AI Servo.

To give an example, I was doing a fairly closeup shot of a person and focused on the eyes, then I move the focus point elsewhere while recomposing. If I pan gradually, say, across the face that is slightly slanted away from the camera, AI Servo kicks in and will not turn off. I think this is what causes the problem that everyone is talking about. It doesn't happen every time, but it happens enough to be a cause for concern.

BTW, I believe moving the focus ring while focus is locked causing AI Servo to kick in is related to this. If you change focus, it's a gradual change in contrast; and then you-know-what is triggered. :-)

I think there should be a way to choose between AI Focus or One Shot Focus in the menus for the creative modes. It's not really adding a feature to the camera -- you still cannot choose to have full time AI Servo (without a mono plug, that is) -- but it takes the unpredictability away from those who want to do the old fashioned focus and recompose. I really hope it's in a future firmware update.

Anthony
1. Focus on whatever you want.
2. Wait for the focus conformation light in the view finder to come
on. (This should be prettry fast depending on what lens you are
using.) If you recompose before this, the camera is still trying
to achieve sharp focus and therefore would focus on the "wrong"
part of the image.
3. Recompose and shoot.

From here, the only way that I can have the AI servo kick in is to
play with the focus ring (can only do this with ring type USM
lens). And this is how I do it when shooting action.

Hope it works for you.

jlo
 
you need a lens that support full time manual focus to do that..or else you risk breaking your lens.
Further tests have decisively shown (on my camera firmware) that if
while having the shutter half pressed, you touch the front knurled
focus ring on the lens, it will start to seek focus regardless of
the lock and act as if it's unlocked. It only needs the lightest of
touches - you don't have to turn it.

Touching the zoom ring doesn't have that effect.

The auto focus apparently detects that it has been moved off its
held setting and attempts to correct that - which then negates the
half-press.

--
Paul Worden

--
Paul Worden
--
I am not an English native speaker!
http://www.pbase.com/zylen
http://www.photosig.com/go/users/userphotos?id=26918
 
There's been a couple of workarounds posted (neither the DOF
preview or switching to MF is ideal, but are workarounds). I think
it would be helpful to figure out what causes AI Servo to trigger
so we know when to expect to need these tricks.

It's been suggested somewhere in this thread that if you hold at
your focus point and half-press to focus (holding still until the
beep), and then recomposing, AI Servo will not kick in. I have
found that this is not the case. You CAN get it to kick in even
after the beep and focus dot lights up if certain conditions exist
(see below). At least that's what happens on my camera (kit lens
and 50mm 1.8, firmware 1.0.2).

I find that, for my camera, AI Servo kicks in if it senses gradual
forward or backward movement. I can move the focus point around
after getting a focus lock and AI Servo usually does not kick in.
ONLY if I point it at something (anything, whether in focus or
not), and that something is moving towards or away from the camera,
AI Servo fires up. Occasionally, when I'm recomposing and I move
the focus point across a surface that slants away from or towards
the camera, AI Servo kicks in.
That could explain what went wrong with a series of shots I took of a dog patiently waiting for a treat. The treat was closer to me, on the edge of a park bench, and the dog was further away on that bench. I thought I had got a focus lock on the treat each time, before recomposing to get more of the OOF dog into the frame (with the treat at the bottom right corner), but each shot is clearly focusing on the dog (not a bad effect, but not the one I wanted).

I've disabled that irritating beep, and assumed that once the red light has stopped flashing on the one active focus point, the focus is locked.
That is the thing that annoys me the
most and makes me wish that I could disable in via the menu.
Yup. It is a useful feature, but only if I can rely on it kicking in only when wanted....
However, unlike what Dave or John said, I cannot get it to kick in
simply by moving the focusing point to the background. Only if AI
Servo starts up via a gradual change in object distance at the
focus point as I described above (or what it perceives as a gradual
change in object distance) before moving the focus point will it
focus on it.

Could somebody please confirm this or add their experience on when
AI Servo kicks in?

Thanks,
Anthony
I'm only focusing on a close subject and then recomposing to get
more background in the picture. I'm not doing anything complicated
or moving around, I'm just panning the camera to get better
composition.
It is frequently a problem when you move from a close subject to
the background and back again. I find Al servo will kick in most
every time when moving from far to near. You just have to be
careful about noting where you are placing the center focusing
point. Don't move around a lot while half pressed, or just plain
hurry up and beat the switch.--
--
John from Southern California
http://www.pbase.com/johnrweb/disneyconcerthall
http://www.pbase.com/domdom
F707 and 300D
 
Hmm, maybe something else is going on? Can we see some samples of an out-of-focus picture?

In the creative modes, I've not had any trouble with the built-in focus lock on the digital rebel (i.e., holding down the shutter release halfway and not letting up until the picture has been taken). This may be the best workaround, since there is no real way of turning off AI Servo in the creative modes. Of course, you can always use one of the basic image modes to restrict the AI Focus to single-shot with the Portrait mode...
I seem to be having the opposite problem that everybody else have.
Last weekend, I went out taking pictures of my girl friend. I
focus on my girlfriend by half-pressing, and then I recompose the
picture.

What I find afterward is that my subject is getting misfocused
because the AI Servo went into action and refocused when I panned
to recompose. What's the trick in keep the camera from refocusing?

--
John from Southern California
http://www.pbase.com/johnrweb/disneyconcerthall
http://www.pbase.com/domdom
F707 and 300D
 
I think this has already been suggested, but have you tried pushing
the "depth-of-field" button after achieving focus lock? If you
push and hold the "depth-of-field" button, focus is locked and the
AI servo won't kick in. You can then recompose with no problems.
I know it means pushing another button, not perfect, but a work
around.
I'm holding a 2.8lb lens with my other hand! Makes it a little difficult to do and hold the camera up.
 
I expect a $900 camera to focus. I expect my $50 camera to focus.
I expect my disposable $3 camera to Focus.

Perhaps that's an unreasonable expectation, but it is my expectation.
It can be used for pro use yes but if you want a camera that is a
pro camera or has better features then pay the extra and buy one..
you get what you pay for.
--
John from Southern California
http://www.pbase.com/johnrweb/disneyconcerthall
http://www.pbase.com/domdom
F707 and 300D
 
That would do it, however, it disables the capability of shooting RAW.
When you recompose the camera automatically switches to AI servo
thinking the subject is moving, the only way to prevent it for me
is to recompose at the speed of light, mine does it all the time,
it does it in any mode as far as i know. I've emailed canon asking
how to disable it all together, but so far no response.
It's not a fix for all cases, but in the case of taking the picture
of a girl friend, the portrait mode should do it. Portrait mode
uses One-Shot AF and will not go into Servo AF.
--
Darryl Hayashida
--

http://www.pbase.com/jthomaslambert
 
Hi i tried it i have the 1.8 50mm lense mounted i still don't get any problems like the guy's are having here?
Let me tyr the kit lens...
Reptiman
Anyway, Reptiman, have you tried to lock focus, point it at
something with a bit of contrast (doesn't have to be in focus) and
walk towards it? That kicks my camera into AI Servo every time, no
matter how long the focus has been locked and me pointing the
camera everywhere (I'm testing in Av mode).

You can also point it at a contrasty surface that's slanted away
from you and move the focus point down that surface, away from you.

My point is that I believe the camera kicks into AI Servo when it
senses a gradual change in object distance or what it perceives as
a gradual change in distance (or perhap a gradual change in
contrast). You can point the locked focus point all over the place
and AI Servo might not kick in, because most changes in distance
and contrast when panning are quite abrupt. However, when the
object is moving towards or away from the camera, or when you're
panning the focus point on a surface that's slanted away from or
towards the camera, AI Servo kicks in (for me).

I'm using kit lens and 50mm 1.8, firmware 1.0.2. This is easier to
trigger with the 50mm or kit lens at full zoom (make sense, because
there's less DOF and more likely there's a contrast change at
different distances).

Anyway, please try it and let us know if AI Servo kicks in for you
too.

Thanks,
Anthony
I been reading the entire tread, and now I'm starting to see people
saying names to others, let's be adult please.

What I suggest is by going step by step, instead to be like a
chicken running with its head cut-off (no offense to anyone), we
should try to differentiate which mode triggers AI Servo AF.

My understanding of the whole issue is this :

The Digital Rebel/300D has all these AF modes :

One-Shot AF
Predictive AI Servo AF,
AI Focus AF (Automatically selects One-Shot AF or AI Servo AF
selected according to shooting mode)

Let's start with the modes that runs and only in One-Shot AF :

Portrait
Landscape
Macro
Night Portrait
Flash Off
A-DEP (creative mode)

Now modes that runs exclusively with AI Servo AF :

Sports

Modes that runs in AI Focus AF which is described as :

AI Focus AF switches between One-Shot AF and AI Servo AF when it
senses that subjects are starting and stopping. It's perfect for
children, pets, wildlife and other unpredictable subjects. My
understanding is, in AI Focus AF, if you're moving closer/further
from the subject, it is possible the camera will go in AI Servo AF,
same for when the subject moves. If the camera doesn't detect any
movement, then it will take a picture in One-Shot AF.

The modes that uses this AI Focus AF are :

Full Auto
Program AE - P
Aperture Priority - Av
Shutter-Priority - Tv
Manual - M

Now from what I gathered, its written that either Single or
Continuous shot (Drive Mode) can use One-Shot AF, AI Servo AF or AI
Focus AF, depending on the modes mentioned above.

Metering modes :

When using M, you have Center-Weighted by default, if you press the
AE-lock button, then you're choosing Partial meteting.

In creative modes (P, AV, TV, A-DEP), Evaluative metering is the
default mode, if you press the AE-lock button, then you're choosing
Partial meteting (9% of the surface of the CMOS sensor)

Any insight ?

--
Eric Cote

More of my photo album found here :

http://community.webshots.com/user/drhangar
--
ReptiMan!
--
ReptiMan!
 
With the kit lens i tried it the only possible way to get it to kick in was if i focused on a somthing and then moved foward very fast i mean as fast as you can... this would be like if you where shooting a dog at a medium running pace thats how fast i had to jult foward to make it work? when moving camera sidways fast it did not kick in..

Most likly it will do the same with my 1.8 lense i just never tested it this way..

Funny thing is i went through 3 rebels to get one that was good and i do remember one of the other 2 had this problem anytime i would compose a shot and go to move and take the picture it always refocused??
maybe some are much more sensitive?
Reptiman
Anyway, Reptiman, have you tried to lock focus, point it at
something with a bit of contrast (doesn't have to be in focus) and
walk towards it? That kicks my camera into AI Servo every time, no
matter how long the focus has been locked and me pointing the
camera everywhere (I'm testing in Av mode).

You can also point it at a contrasty surface that's slanted away
from you and move the focus point down that surface, away from you.

My point is that I believe the camera kicks into AI Servo when it
senses a gradual change in object distance or what it perceives as
a gradual change in distance (or perhap a gradual change in
contrast). You can point the locked focus point all over the place
and AI Servo might not kick in, because most changes in distance
and contrast when panning are quite abrupt. However, when the
object is moving towards or away from the camera, or when you're
panning the focus point on a surface that's slanted away from or
towards the camera, AI Servo kicks in (for me).

I'm using kit lens and 50mm 1.8, firmware 1.0.2. This is easier to
trigger with the 50mm or kit lens at full zoom (make sense, because
there's less DOF and more likely there's a contrast change at
different distances).

Anyway, please try it and let us know if AI Servo kicks in for you
too.

Thanks,
Anthony
I been reading the entire tread, and now I'm starting to see people
saying names to others, let's be adult please.

What I suggest is by going step by step, instead to be like a
chicken running with its head cut-off (no offense to anyone), we
should try to differentiate which mode triggers AI Servo AF.

My understanding of the whole issue is this :

The Digital Rebel/300D has all these AF modes :

One-Shot AF
Predictive AI Servo AF,
AI Focus AF (Automatically selects One-Shot AF or AI Servo AF
selected according to shooting mode)

Let's start with the modes that runs and only in One-Shot AF :

Portrait
Landscape
Macro
Night Portrait
Flash Off
A-DEP (creative mode)

Now modes that runs exclusively with AI Servo AF :

Sports

Modes that runs in AI Focus AF which is described as :

AI Focus AF switches between One-Shot AF and AI Servo AF when it
senses that subjects are starting and stopping. It's perfect for
children, pets, wildlife and other unpredictable subjects. My
understanding is, in AI Focus AF, if you're moving closer/further
from the subject, it is possible the camera will go in AI Servo AF,
same for when the subject moves. If the camera doesn't detect any
movement, then it will take a picture in One-Shot AF.

The modes that uses this AI Focus AF are :

Full Auto
Program AE - P
Aperture Priority - Av
Shutter-Priority - Tv
Manual - M

Now from what I gathered, its written that either Single or
Continuous shot (Drive Mode) can use One-Shot AF, AI Servo AF or AI
Focus AF, depending on the modes mentioned above.

Metering modes :

When using M, you have Center-Weighted by default, if you press the
AE-lock button, then you're choosing Partial meteting.

In creative modes (P, AV, TV, A-DEP), Evaluative metering is the
default mode, if you press the AE-lock button, then you're choosing
Partial meteting (9% of the surface of the CMOS sensor)

Any insight ?

--
Eric Cote

More of my photo album found here :

http://community.webshots.com/user/drhangar
--
ReptiMan!
--
ReptiMan!
--
ReptiMan!
 
And this is real annoying when I use a polarizer. Just the slightest touch on the polarizer to change its angle causes the focus to go crazy for static landscape shots. It drives me nuts sometimes.
Al
Further tests have decisively shown (on my camera firmware) that if
while having the shutter half pressed, you touch the front knurled
focus ring on the lens, it will start to seek focus regardless of
the lock and act as if it's unlocked. It only needs the lightest of
touches - you don't have to turn it.

Touching the zoom ring doesn't have that effect.

The auto focus apparently detects that it has been moved off its
held setting and attempts to correct that - which then negates the
half-press.

--
Paul Worden

--
Paul Worden
 
You are probably a very nice person, SFPJ, etc., etc. so my apologies if this response upsets you in any way but your post really hit my hot button! Do you use that 'I'm 50 years old' excuse a lot? Are you only partially alive now that you are 50? Geez I hate that attitude! I run across it all the time, drives me nuts!

I'm 50 and I do everything my kids do (all 4 are in their twenties). I kick their butts in video games (may favourite games, that is, won't talk about the others). I kick their butts in lots of stuff (and get mine kicked once in a while too). But the point is, I can learn as fast or faster, I can do pretty much anything they can do. And it's not that they are couch potatoes. Three out of four have university degrees, all are very physically active, etc. etc.

Sure you might have the odd pain here and there (50 is 50) but geez who doesn't. Have you forgotten that you had the odd cramp when you were 16? So get up off your butt, and quit using that pathetic excuse (or I'll track you down and kick your butt myself, or get mine kicked, doesn't matter, at least you'll DO SOMETHING)!! Your excuse is especially annoying when it comes to mental challenges, like learning a new camera, no excuse there.

(And you were probably just using the 'I'm 50' routine as a conversation starter. Wrong choice. lol)
I seem to be having the opposite problem that everybody else have.
Last weekend, I went out taking pictures of my girl friend. I
focus on my girlfriend by half-pressing, and then I recompose the
picture.

What I find afterward is that my subject is getting misfocused
because the AI Servo went into action and refocused when I panned
to recompose. What's the trick in keep the camera from refocusing?

--
John from Southern California
http://www.pbase.com/johnrweb/disneyconcerthall
http://www.pbase.com/domdom
F707 and 300D
--
SFJP
http://www.pbase.com/sfjp
 
I agree, it is a real pain, you should be able to trust that functionality to just work.

My read on it is they should be able to fix it in a s/ware update, we all want the 10d functionality, but the reality is that won't happen, but if ai-servo was altered so it worked more accurately ( if the whole scene changes don't shift focus point !! ). It would be a very good start I think.

Nigel
Which version of the bios in the camera are you running ?, I'm @
1.0.2 from memory & I am wondering if the update to 1.1.1 fixed
this.

This problem is annoying to me also, though the metering I am not
so unhappy about, I've getting more adept at compensation
calculation in my head :).

Nigel
I think this has already been suggested, but have you tried pushing
the "depth-of-field" button after achieving focus lock? If you
push and hold the "depth-of-field" button, focus is locked and the
AI servo won't kick in. You can then recompose with no problems.
I know it means pushing another button, not perfect, but a work
around.
yes that's a workaround for stopping the AI servo. It is hard to
hand held steady at 300mm and hold that button and still get a
sharp shot though...I tried it and it does work but you need very
fast shutter speeds to freeze the camera shake if you push that
button. It's not a very convenient position to hold a lens steady.

Now I wish there was such work around for the meetering. swithing
to manual focus is even more hassle and you need to pet around the
lens to find that switch when you're trying to take the photo at
the same time. This woudl be really convenient if one could freeze
the time.
I seem to be having the opposite problem that everybody else have.
Last weekend, I went out taking pictures of my girl friend. I
focus on my girlfriend by half-pressing, and then I recompose the
picture.

What I find afterward is that my subject is getting misfocused
because the AI Servo went into action and refocused when I panned
to recompose. What's the trick in keep the camera from refocusing?

--
John from Southern California
http://www.pbase.com/johnrweb/disneyconcerthall
http://www.pbase.com/domdom
F707 and 300D
--
I am not an English native speaker!
http://www.pbase.com/zylen
http://www.photosig.com/go/users/userphotos?id=26918
--
I am not an English native speaker!
http://www.pbase.com/zylen
http://www.photosig.com/go/users/userphotos?id=26918
 
You're right, the older I become the faster I can learn or invent (I'm a researcher) meaningful things, maybe the reason is that older peploe, before their brain decays, have learned a lot of logical structures in their life to organize new knowledge. But, it's my experience that I have more and more difficulty (or reluctance) to memorize detailed pieces of information that are not deducible from obvious principles. This is the case for the various modes (AF, metering) to which the 300 D switches automatically when you change some unrelated settings without even warning you. I think that younger people have less difficulty to memorize such non logically simplifiable pieces of data. Otherwise, I can still kick the butt of many peoples, don't be doubting that! Cheers
I'm 50 and I do everything my kids do (all 4 are in their
twenties). I kick their butts in video games (may favourite games,
that is, won't talk about the others). I kick their butts in lots
of stuff (and get mine kicked once in a while too). But the point
is, I can learn as fast or faster, I can do pretty much anything
they can do. And it's not that they are couch potatoes. Three out
of four have university degrees, all are very physically active,
etc. etc.

Sure you might have the odd pain here and there (50 is 50) but geez
who doesn't. Have you forgotten that you had the odd cramp when
you were 16? So get up off your butt, and quit using that pathetic
excuse (or I'll track you down and kick your butt myself, or get
mine kicked, doesn't matter, at least you'll DO SOMETHING)!! Your
excuse is especially annoying when it comes to mental challenges,
like learning a new camera, no excuse there.

(And you were probably just using the 'I'm 50' routine as a
conversation starter. Wrong choice. lol)
--
SFJP
http://www.pbase.com/sfjp
 
You're right, the older I become the faster I can learn or invent
(I'm a researcher) meaningful things, maybe the reason is that
older peploe, before their brain decays, have learned a lot of
logical structures in their life to organize new knowledge. But,
it's my experience that I have more and more difficulty (or
reluctance) to memorize detailed pieces of information that are not
deducible from obvious principles. This is the case for the various
modes (AF, metering) to which the 300 D switches automatically when
you change some unrelated settings without even warning you. I
think that younger people have less difficulty to memorize such non
logically simplifiable pieces of data. Otherwise, I can still kick
the butt of many peoples, don't be doubting that! Cheers
Thanks - you've managed to put into words more or less my exact thoughts on this subject. I'm not even nearly 50, but I find the (to me) seemingly illogical way that people organise things - this camera being one example - quite exasperating.

Time to get back on-topic!

--
David Barker
 
it just amazes me after reading all these posts how
Canon ended up overcomplicating the 300D just
because they had to dummify it in the first place
lol.. I believe Canon should make the 300D fuctionally
equal to the 10D and charge 100$ less for the
plastic body and that would be the end of it and
of everyones' problems.
I seem to be having the opposite problem that everybody else have.
Last weekend, I went out taking pictures of my girl friend. I
focus on my girlfriend by half-pressing, and then I recompose the
picture.

What I find afterward is that my subject is getting misfocused
because the AI Servo went into action and refocused when I panned
to recompose. What's the trick in keep the camera from refocusing?

--
John from Southern California
http://www.pbase.com/johnrweb/disneyconcerthall
http://www.pbase.com/domdom
F707 and 300D
 
it just amazes me after reading all these posts how
Canon ended up overcomplicating the 300D just
because they had to dummify it in the first place
lol.. I believe Canon should make the 300D fuctionally
equal to the 10D and charge 100$ less for the
plastic body and that would be the end of it and
of everyones' problems.
Uhhh, thats gonna be the Digital Rebel II ;) to be released when the 20D is available. ;) again
I seem to be having the opposite problem that everybody else have.
Last weekend, I went out taking pictures of my girl friend. I
focus on my girlfriend by half-pressing, and then I recompose the
picture.

What I find afterward is that my subject is getting misfocused
because the AI Servo went into action and refocused when I panned
to recompose. What's the trick in keep the camera from refocusing?

--
John from Southern California
http://www.pbase.com/johnrweb/disneyconcerthall
http://www.pbase.com/domdom
F707 and 300D
 
Thanks for your thoughful reply. Yes, I too, feel I can actually learn faster as I get older but there is some truth to your comments about difficulty in learning ill-logical systems. My kids find the most bizarre solutions to some problems. Especially when it comes to computers and the like. So maybe our creativity does wane with age (while our logical thought patterns strengthen) . . .

Oh well, carry on and thanks again for the thoughful reply to my rant. And good luck with your new camera! I hope to get one soon.
I'm 50 and I do everything my kids do (all 4 are in their
twenties). I kick their butts in video games (may favourite games,
that is, won't talk about the others). I kick their butts in lots
of stuff (and get mine kicked once in a while too). But the point
is, I can learn as fast or faster, I can do pretty much anything
they can do. And it's not that they are couch potatoes. Three out
of four have university degrees, all are very physically active,
etc. etc.

Sure you might have the odd pain here and there (50 is 50) but geez
who doesn't. Have you forgotten that you had the odd cramp when
you were 16? So get up off your butt, and quit using that pathetic
excuse (or I'll track you down and kick your butt myself, or get
mine kicked, doesn't matter, at least you'll DO SOMETHING)!! Your
excuse is especially annoying when it comes to mental challenges,
like learning a new camera, no excuse there.

(And you were probably just using the 'I'm 50' routine as a
conversation starter. Wrong choice. lol)
--
SFJP
http://www.pbase.com/sfjp
 

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