# AF - one shot with 5dmkIII or 1dx



## paolotaverna (May 21, 2013)

Quick question, 

In one shot mode, do the expanded AF points play any role?

Until now I always thought it was for AI Servo only...but it's been a few times, where I am in One shot and Expanded points...when I focus with the "bigger" center point, the small one lights up (meaning that the confirmation AF comes from one of the expanded points)

thank you


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## neuroanatomist (May 21, 2013)

Focus mode (One Shot, AI Servo) and AF point selection (single, expanded, spot, zone, full auto) are independent settings. So yes, if you are in One Shot and have AF Point Expansion enabled, if focus can't be achieved with the selected point, an expansion point will be used.


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## paolotaverna (May 21, 2013)

thx


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## wickidwombat (May 22, 2013)

yes sometimes this is good ie cant lock the face might lock the chest 
or it can be bad cant lock the face so it locks onto a tree in the background
its one of those things you need to be aware how it works and in what areas which setting works best
the new AF system is alot more complicated so reading up and getting a good understanding of how each mode works is essential to avoid frustration, none are a magic bullet but each have their own strong and weak points


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## alexanderferdinand (May 22, 2013)

The expanded points are the backup, if the main field doesnt catch up.
The more points are allowed to find structure to focus, the more it could be unpredictable.


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## Dwight (May 22, 2013)

They're not mutually exclusive. I think the expanded points were designed to be used for moving subjects (AI Servo). I choose my expanded AF points (either four or eight) depending on how fast my subject is, how big it is, and how fast I can keep it in the frame. I always 'Spot AF' or '1 pt AF' for static objects...more so with portraits wherein one needs precise focus (i.e. eye). Expanding the focus point in that scenario is calling for trouble which might focus on the nose or forehead instead.


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## paolotaverna (May 22, 2013)

thx gents! it confirms my worries  so no expanded in one shot


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## Dick (May 22, 2013)

paolotaverna said:


> thx gents! it confirms my worries  so no expanded in one shot



Too bad there is no decent way to toggle between the modes. I would really appreciate it if the DOF button for example would in addition to servo (which doesn't even stay on when you release the button) also temporarily add the expanded points, a pre-selected af case and even a higher shutter speed. Custom modes are good for this, but you can't change between them in fast pace. The basic assumption is that the photographer knows before hand when to use servo.


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## neuroanatomist (May 22, 2013)

Dick said:


> Custom modes are good for this, but you can't change between them in fast pace. The basic assumption is that the photographer knows before hand when to use servo.



Well, on the 5DIII you cannot. On my 1D X, I have mode selection assigned to the M.Fn button, which is right next to the shutter button. C2 is One Shot with single point selection, C3 is AI Servo with 61pt auto selection and a faster minimum shutter speed. A slight move of my index finger and one button press, I'm good to go.


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## Skulker (May 22, 2013)

If you press the top right button on the back (the AF point selection button) then the M-fn button you can toggle through the choice of AF area selections. Each press of the M-fn button takes you to the next option, about a second to select the one you want. 

You may then have to select the area you want with the joy stick. 

Works with both cameras and in auto servo and single.


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## Chris Burch (May 22, 2013)

I'm confused by some of these responses and I think you're getting bad information. The AF selection points and AF mode are independent. The expansion points work perfectly fine in One Shot -- it's your personal preference on how useful/effective the extra points are for your shooting needs. For however many point are selected the camera will lock focus on the activated point (or points) it determines is the most ideal candidate based on distance, contrast and whatever other mojo is going on the in the AF chip. I typically use a 9-pt square for focus and if the point lights up off of the face of my subject I just recompose -- I very rarely hit focus on the background. This works great for me when shooting events because I just need to get a point to lock anywhere on face.

For switching modes, you can do so in less than a second on the 5D3 using custom modes...I do it all of the time without missing a beat. Once you get used the the action to switch modes, the dial isn't bad at all. On the 1DX, you have no excuses to complain. Using the custom route as Neuro suggested is nearly instantaneous. You can even tell the camera how many modes to toggle through, so you aren't wasting button pushes. Additionally, and more in line with what someone mentioned with the DOF button, you can assign either of the custom buttons to activate Servo while pushed and return to One-shot when released. I have configuration on my 1DX with the other custom button set to toggle between my current AF point selection and all points active, so i can very quickly expand to all points to catch a moving subject.


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