do you manually switch AF points frequently?

[emanresu]

This is a bit embarrassing for me to ask because it seems to be so fundamental , but if I don't ask I will never learn.  Yesterday I went with a group of friends and took my camera to take pictures.  When I got home, I found many of the pictures out of focus.  Before that, I had been shooting scenes most the time, and even if there were people, I only took portraits of one person at a time, but never complex scenes with many people in the frame.

The cause of the problem was the AF points.  I usually set all the AF points to be active, or set the center one.  With all 9 points active, the algorithm picks the closest object to focus, and that is usually the table, or the beer keg (definitely an issue with composition here too, but shall we ignore it for now?) .  And when it is set to the center one, it is the background in the focus because people are having conversations and each one takes up one side of the frame, just missed by the center focal point.

I can certainly switch the active AF points as needed, but that would take time and I will miss some interesting interactions between people (well, with out of focus pictures, I haven't exactly captured them either ).  So I am just wondering if there is a faster way to focus on the part of the frame as needed.

The answer to this question would also help me on portraits as well.  All texts say when taking a portrait, I need to set the focus on their eyes.  But in the pictures I took, the focus is usually on the nose if it is a close-up, or on the chest if it is a little far-away, and the eye portion of the face rarely fall onto any AF points conveniently.  So how do I quickly focus on people's eyes without resolving to manual focus?

Funny that it never was an issue with a point-and-shoot...

[Bob Atkins]

Personally I use the center AF point 95% of the time, but I'll focus and recompose (keeping the shutter 1/2 pressed) when my subject isn't in the center of the frame.

See http://www.bobatkins.com/photography/technical/focus_recompose.html

[emanresu]

awesome! Thanks Bob.  That's why I love your site - you foresee questions from beginners and write articles about them, and not only that, you also back each article with sound scientific analysis and reasoning so we can have an in-depth understanding of why things are the way they are.

[KeithB]

Generally, I leave it on auto-focus-point and make sure it is focusing in the right spot.  Unless I am taking macro shots of bugs, or shooting wildlife, then I put it in the center.  (or shooting through a fence)

[emanresu]

Thanks Keith for sharing your style.  I did that, but as you have read, the auto selection picked the table because it was the closest object.  I definitely need to learn how to be cool before pressing the shutter, so to make sure everything is correct

[klindup]

Having grown up and learned my photography with manual focus cameras and lenses and not had any problems I still have a nagging thought that autofocus is more trouble than it is worth.  It used to feature on cine cameras and I can see the need there but why do we need it on still cameras?

Ken

[Bob Atkins]

Because 99% of the time AF is faster and more accurate than manual focusing. There are some situations (e.g. macro work) where precise positioning of focusing is better done manually than with AF, but I don't think you'd find many sports or nature photographers (or photojournalists) who would consider going back to manual focus. For landscape photographers it's probably not needed, but you can always turn it off and focusing via Live View is very accurate if you aren't in a hurry.