AI Servo vs One shot

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I know! I've been through 20 threads already but didn't find the answer I was looking for I think.

Now I know the differences and use them accordingly. The only real question I have is: Why would you use One Shot?

Personally, I use it myself as well: Buildings, landscape, scenes w/e. I only do so because I feel like I should: It's what you're 'supposed' to use. I use AI Servo when subjects are moving, but I was just thinking why would you use One Shot at all? AI Servo starts working when the subject is moving, but as long as it isn't moving, it doesn't matter, am I right? Are there any disadvantages to using AI Servo when the subject isn't moving?

The only situation I could think of in which you would actually wouldn't be able to use is if you want to use FTM?
(and a second scenario is if one would like the subject out of focus, but let's not presume that...)

Please forgive my noobish question, but it just doesn't seem very logical to not use AI Servo 95% of the time.

Can't Focus and recompose with AI Servo.

bior wrote in post #12554092
Can't Focus and recompose with AI Servo.

Wouldn't it then be easier to just flick the AF to MF button. One tiny movement, instead of having to press a button+use the wheel (and personally I'm not that good that I don't have to look what setting I put it on).

I have whichever Custom Function enabled that turns the joystick into the focus point selector. It took a little while to get the hang of it, but now I can very rapidly choose which focal point I'm using, while looking through the viewfinder.

There are many different ways to achieve proper focus with the EOS system. Some people keep their AF-ON button for focus and only use the shutter button for metering and shooting. And the super-zooms have focus recall on their barrels.

Point is, there are many autofocus methods available and each photographer can choose the most appropriate for the situations they find themselves in. Canon's cameras tend to be VERY well designed, and no feature is present accidentally. That there are so many different ways to focus means that no one way is perfect for everyone in every situation. If there were, there would be only one way to focus.

bior wrote in post #12554092
Can't Focus and recompose with AI Servo.

Not true. My back button is used for focusing and shutter button for firing the shot. Take your thumb off the back button and you can recompose to your hearts content. My camera is in AI-Servo all the time.

Gatorboy wrote in post #12554224
Not true. My back button is used for focusing and shutter button for firing the shot. Take your thumb off the back button and you can recompose to your hearts content. My camera is in AI-Servo all the time.

For me, that is the biggest advantage to having back button focus - the ability to use Servo with an on and off function.

Absolutely. It is up to each photographer to explore the combinations and find what works.

Gatorboy wrote in post #12554224
Not true. My back button is used for focusing and shutter button for firing the shot. Take your thumb off the back button and you can recompose to your hearts content. My camera is in AI-Servo all the time.

Boy, I was wondering what he was talking about until I read your post, then I remembered that the majority of people probably use half-press to focus. I've been using the back button for so long I forgot all about it.

Gatorboy wrote in post #12554224
Not true. My back button is used for focusing and shutter button for firing the shot. Take your thumb off the back button and you can recompose to your hearts content. My camera is in AI-Servo all the time.

+1 This is how I've been working ever since I found out about backbutton AF - its a very powerful and simple feature and really makes things a lot easier. Especailly so since not all lenses have the MF/AF button in an easy position - eg my 70-200mm its very easy to reach all the switches - whilst many of my other lenses the AF/MF button is way at the back near the lens mount - shifting your hand back and fumbling around takes time - far more time than just not pressing the backbutton

Combined with USM/HSM lenses its great - you've all the time manual focus and you can use AF in a blink against a static or moving subject.

I use AI Servo 90% of the time without back button focusing. Mostly for street candids in low light.

Works for me.

bior wrote in post #12554223
I have whichever Custom Function enabled that turns the joystick into the focus point selector. It took a little while to get the hang of it, but now I can very rapidly choose which focal point I'm using, while looking through the viewfinder.

Oooh me want!!! Anyone know the function for that? Also while I am asking questions is there a way when you playback pictures on your camera that portraits are using the whole screen instead of it being rotated and it into the small screen?

50d

sorry for the hijack

domat wrote in post #12555132
Oooh me want!!! Anyone know the function for that?

Look in your manual under Custom Functions. On the 20D it's C.Fn-13 (2)

NeverSummer wrote in post #12554562
Boy, I was wondering what he was talking about until I read your post, then I remembered that the majority of people probably use half-press to focus. I've been using the back button for so long I forgot all about it.

One you go back button, you never go back.

TijmenDal wrote in post #12553993
Searchbar!

I know! I've been through 20 threads already but didn't find the answer I was looking for I think.

Now I know the differences and use them accordingly. The only real question I have is: Why would you use One Shot?

Personally, I use it myself as well: Buildings, landscape, scenes w/e. I only do so because I feel like I should: It's what you're 'supposed' to use. I use AI Servo when subjects are moving, but I was just thinking why would you use One Shot at all? AI Servo starts working when the subject is moving, but as long as it isn't moving, it doesn't matter, am I right? Are there any disadvantages to using AI Servo when the subject isn't moving?

The only situation I could think of in which you would actually wouldn't be able to use is if you want to use FTM?
(and a second scenario is if one would like the subject out of focus, but let's not presume that...)

Please forgive my noobish question, but it just doesn't seem very logical to not use AI Servo 95% of the time.

I would keep it on One Shot for landscape. AI Servo is for where the subject is very fast and/or very unpredictable

You might also consider AI Focus in low light so that the focus assist on your Canon flash provides perfect focus every time.

I like when it beeps to confirm focus. So, I use one-shot most of the time.