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Super Contributor
Posts: 187
Registered: ‎01-31-2017

Autofocus points

I have been walking around and shooting with the full grid of AF points selected, believing it best. In fact, it may be worse, as the nearest object is what ends up being in focurs, which is not always the goal.

 

I now select the center point when in Av or Tv. The problem is that in my camera, the T6, the AF points are hard to see, whether all are selected or just one. That, so far, is the thing I dislike most about the T6. Still, the camera has been excellent and is meeting my goal of helping me develop some skill in DSLR photography without overspending. But back to AF. Do you guys typically shoot using the whole grid or just one point? And do you have a difficult time seeing the points?

Esteemed Contributor
Posts: 2,172
Registered: ‎11-14-2012

Re: Autofocus points

I haven't used a rebel much but in general use a single point for static stuff when the camera might choose the other things in the viewfinder & the full array (in AI Servo) for moving targets. If you're really good at panning & using a slower than suggested shutter speed (to get background blur etc) using a single point helps IF you're steady enough to place that point on a specific area of your target. (example being the door handle or drivers helmit of a race car or pilot of a plane in flight.)

"A skill is developed through constant practice with a passion to improve, not bought."
Honored Contributor
Posts: 5,251
Registered: ‎08-13-2015

Re: Autofocus points

Set your camera to have the center AF point manually selected in all of the Creative shooting modes.  Use "One Shot" focus mode.  The only time you should need to use AI Servo is if you are photographing a subject that is changing its' distance between you and the camera.  Forget about using AI Focus mode, BTW.  

 

Depending upon the scene, the AF points may be hard to see.  In time you will get used to it, especially if you always use the center AF point.  You should also be able to set your camera to light the AF point [use the center one] that locks focus, and keep it lit once focus is locked.  

 

Why use the center AF point?  Because in most of Canon's DSLRs, the center AF point is special.  It is the most accurate and sensitive.

 

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"I don't rent software. I use Photoshop CS6, ACR 9.8 and Lightroom 6.8 ."
Esteemed Contributor
Posts: 4,318
Registered: ‎11-13-2012

Re: Autofocus points

Unless I have special conditions I use the center point for the very reasons you mention.

 

i don't need to see the point since I know its in the center.

John Hoffman
Conway, NH

1D X, Rebel T5i, Many lenses, Pixma PRO-100, MX472
Esteemed Contributor
Posts: 3,048
Registered: ‎06-11-2013

Re: Autofocus points

I noticed you mentioned you select the center point "when in Av or Tv".   A similar topic came up on another forum and the person posted the message said they were told that those modes require the center point (they do not).  So it made me wonder if you hadn't run across someone saying the same thing.

 

The exposure modes (Av, Tv, M, or P) and the focus modes (auto-select, single point, etc.) are not linked in any way.  You can use any focus mode with any exposure mode.

 

The topic on the other forum also provoked a healthy discussion on how people choose their focus modes.  

 

As you're already aware, the camera's algorithm when allowed to use all focus points is to focus on the point that can achieve focus at the nearest focusing distance to the camera.   Selecting a single point forces the camera to use your point.

 

But this shifts to the topic of doing the "focus and recompose" technique because usually the subject composition wouldn't put your subject precisely in the center of the frame.  Photographers tend to point at the area where they want focus, let the camera focus, then recompose to take the shot.

 

This technique usually works but it also isn't without it's risks.  The focus distance for the lens is usually designed to be nearly "flat" (but it's never perfectly flat.)  Anyway, if you use a very shallow depth of field, and need critical focus on a subject (suppose you achieve critical focus at the center point on a subject's eye) and then re-compose the camera, that "recompose" just tilted the plane of focus and your intended focus point probably no longer has the focus accuracy you wanted.

 

You would likely only need to worry about this if using a very shallow depth of field (low focal ratio, close focusing distance, etc.) and certainly wouldn't be a problem at higher focal ratios.  But it is something to just file in the back of your mind.  If you want to fuss over focus accuracy then you probably do want to select the focus point nearest to where you intend to compose your subject to minimize any errors introduced by recomposing the shot.

 

 

 

In answer to your question, yes I typically do select a single focusing point.  

 

 

Tim Campbell
5D III, 5D IV, 60Da
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