Center auto focus point or other AF points

[tecboy]

Pretty much all the times I use center AF point. The only time I use other AF points is I use a tripod and the subject is not centered. I have never used full AF points. I don't like the result. Just curious, what AF points do you use?

 

[SCraig]

The center point the majority of the time. If I want to offset the point of focus (as when I want to focus on a subject's eye but the eye is not in the center of the screen) then I use a different AF point. My camera is, however, set so that *I* pick the AF point, not the camera.

 

[frommrstomommy]

I also have mine set so that I choose the AF point.. I use a center point more than anything else but I do get plenty of use out of others as well. I move it around constantly.

 

[Derrel]

Depends on the specific camera and its AF system. Many times, in marginal/difficult conditions, I will select a group AF point scheme, one that uses more than one but less than a dozen out of 51 AF points. FOr example, indoors, when focusing a slower zoom lens and using an off-camera flash, I will use a Group Dynamic AF system so that I can get faster, more-sure lock-on with a "slow" lens, like an f/3.3~4.5 zoom lens. Also, with fast but longer lenses like the 50/1.,8 or 85/1.8 indoors, also using off-camera flash, I find that using more than one AF point means I do not have to focus/recompose, but can simply usew the 4-way controller on the back of the camera, and shift the AF to the area I want, and the camera can easily focus even in very bad light.

For focusing on really fast-moving stuff, I prefer a group AF approach. It gives the computer more than just one,single AF point, and eliminates the opportunity for that one,single AF point to get a No DATA response when it lands on a flat-toned subject. It's kind of like the difference between one-eyed vision, and binocular vision...

 

[12sndsgood]

i generally use the single focus point, but its rarely in the center.

 

[cynicaster]

Ever since I learned the difference between “cross” and “line” type autofocus points, I’ve used my center one over 95% of the time, because it’s the only cross type in the array.

Of course, this is only an issue on ghetto cameras like my T3i—higher end cameras have all cross type points, and more of them.

Using the center point with a focus/recompose is usually just fine in most situations, but it falls apart when, for example, using the common 50mm f/1.8 wide open at a fairly close distance, because the DoF is so shallow that the slight movement of the camera during the recompose step can be enough to throw your intended focus askew.

I believe this very problem, along with the general softness of that lens at wide open, is the reason why you see threads popping up almost daily asking about “focus problems when using 50mm”.

 

[PropilotBW]

Sometimes I leave it centered and recompose after focusing, other times I move it around.

Edit: and I just figured out the my D5100 has only one cross-type focus point, the center. I wonder if my shots will turn out better if I utilize that focus point, versus moving it around?

 

[TCampbell]

On previous cameras it really depended on the shot, the amount of light and contrast. A single-axis AF point is fine when you've got a high-contrast subject for it to lock onto and enough light. In poorer contrast or with lower light, I favor the center point -- which not only provides cross-type focus, it often is capable of working in lower light.

With my 5D III I actually do use _all_ of the focus points. The focus system is amazing and has never let me down. I've taken the time to learn about the various focus configurations and modes (single point, reduced single point, expanded cross, expanded box, zone, and auto selection.)

I tended to avoid auto-selection prior to the 5D III. On the 5D III I'll use auto-selection only when I'm using the intelligent tracking (because it can transfer focus to any point in the array and it visibly shows you which points it's using as your subject moves around.) This is great for for shooting moving action. When not shooting action, I almost never use the auto-selection and mostly pick the focus points or zones I want to use.