One Shot Auto Focus

[mxride]

Can someone explain One Shot Auto Focus to this newbie. I guess its only available to the Rebel with the hack.

[PacAce]

With One Shot Auto Focus, the focus is locked in as soon as you press (or half press) the shutter release button and it stays locked until the shot is taken or shutter button is is no longer pressed down. The One Shot Focus is automatically selected in a some of the Basic Zone modes but can't be set in the Creative Zone modes, except in A-DEP mode, without the hack firmware.

[lmelendez]

ok, so this is another newbie that requires some explanation about this.

I have a rebel, I have the hack but don't rememer changing any setting for One Shot Auto Focus. I normally lock the focus (pressing the button half way down), then I recompose the picture and then press the button all the way down.

My question is... The one shot auto focus is different from what I am doing? or... is it what I am doing but never realized that the hack was allowing me to do that?

Thanks!

Leo.

[cmM]

if you don't have any moving objects in the frame you couldn't tell the difference between on shot and AI focus. AI focus would be the same thing, except that it starts hunting (switched to AI servo). as soon as it senses movement. If you haven't made any changes to the focus, you're probably in AI Focus mode.

[lmelendez]

if you don't have any moving objects in the frame you couldn't tell the difference between on shot and AI focus. AI focus would be the same thing, except that it starts hunting (switched to AI servo). as soon as it senses movement. If you haven't made any changes to the focus, you're probably in AI Focus mode.

Hi cmM,
AI Servo is enabled only in sports mode. Does the AI focus does the same thing when I'm not in the sports mode??

mmm, this is getting really interesting....

Leo.

[cmM]

AI Focus and AI Servo are 2 different modes. In AI Servo the focus is a constant hunt as it assumes there is movement. AI Focus only starts hunting when it senses movement. I'm not 100% positive, but I'm sure some correct me if I'm wrong.

[Jesper]

Just to explain the three different focussing modes:

1. One Shot: You half-press the shutter button, the camera focusses, as soon as the subject is in focus it stays locked (doesn't re-focus) as long as you hold the shutter button halfway down.

2. AI Servo: You half-press the shutter button and the camera focusses continuously. You will not get a "beep" that confirms the focus, because it will not lock the focus. This is good for tracking moving objects (with sports, for example) - the camera will try to keep the moving object in focus.

3. AI Focus: This is a combination of One Shot and AI Servo. The camera will initially behave the same as in One Shot mode, but if it detects something that moves, it will automatically switch to AI Servo and track the moving object.

On the 10D and 20D, you can select any of these three modes. On the 300D / Digital Rebel without the hack, you can't freely select any of these three modes (see the manual of your Digital Rebel for info on how it works). I don't know how it works when you have the hack (I have a 10D).

[Mogwyth]

1. One Shot: You half-press the shutter button, the camera focusses, as soon as the subject is in focus it stays locked (doesn't re-focus) as long as you hold the shutter button halfway down.

2. AI Servo: You half-press the shutter button and the camera focusses continuously. You will not get a "beep" that confirms the focus, because it will not lock the focus. This is good for tracking moving objects (with sports, for example) - the camera will try to keep the moving object in focus.

3. AI Focus: This is a combination of One Shot and AI Servo. The camera will initially behave the same as in One Shot mode, but if it detects something that moves, it will automatically switch to AI Servo and track the moving object.


You get 1 and 3 with the hack, 2 does not work properly although there are one or two get arounds.

[HJMinard]

Just for clarification for the "newbies" ... Without the hack and in AI Focus mode the DRebel will - most of the time - act as described (same as One Shot) for static subjects. Occasionally, however, my DRebel would interpret my movement (recomposing after achieving focus) as subject movement, and the automatic AI Focus/AI Servo function would kick in.

That can be quite frustrating. The hack, enabling One Shot mode, resolves this issue.

[selym]

Could one of you esteemed members check my thread on "Lens refusing to focus,Help" and advise are some of the comments relevant above, aare ppropriate to my problem. It's a little frustrating, but the lens on the 300d is hunting and we don't know why.


Selym

[selym]

so

[CyberDyneSystems]

Selym,

You do not provide a link in any of these requests to the thread in question,

... and if we are discussing the same subject,. it is best to do so within an existing thread,. so

What's your question? :)

[selym]

not sure how to link threads..so I'll explain...

Brother has a 300D ..the lens of which is hunting....not allowing focus or shots to be taken....we've interchanged lens with my 300d lens and compared detail re menu etc....no avail...etc so am reasonably clear that it is the camera or a setting, but not sure which....could A1 servo mode cause this or AE lock etc??..If so, suggestions to overcome...

new to digital so am struggling a bit..

selym...

[HJMinard]

not sure how to link threads..so I'll explain...

Brother has a 300D ..the lens of which is hunting....not allowing focus or shots to be taken....we've interchanged lens with my 300d lens and compared detail re menu etc....no avail...etc so am reasonably clear that it is the camera or a setting, but not sure which....could A1 servo mode cause this or AE lock etc??..If so, suggestions to overcome...

new to digital so am struggling a bit..

selym...

If your subject is not moving, then the only way the DRebel should be in AI Servo focus is if it's set on "Sports" mode. In any other mode, the lens should not be hunting (assuming appropriate lighting for autofocus to function properly).