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Unless I have to shot a person or an object which moves, I set my camera to use only one focus point at the middle.

It feels just more natural and so easy: when I need to focus on something which is not in the center of the photo, I start by focusing on it, then move my camera to take a shot. When doing otherwise, I failed to capture numerous moments because of the camera deciding to focus somewhere else.

On the other hand:

  • My Nikon D7000 has 39 focus points, and newer and more expensive cameras have even more. Also, the factory settings are to keep all the available focus points active, including, I believe, on professional cameras such as Nikon D4.

  • I often see people doing DSLR reviews keeping all the focus points active.

  • Ken Rockwell suggests keeping the default auto-focus settings, highlighting the fact that the camera figures very well which point should be used to focus.

Have I misunderstood how to use properly all auto-focus points settings? What could explain that I find it much easier to use a single focus point, while it's not the case for many people?

  • 6
    1. Be aware that focusing on the center point then moving the camera can cause issues with accuracy 2. Be aware that Ken's website is for entertainment purposes only. – dpollitt Jul 17 '14 at 22:17
  • That's what I do. I have no idea why modern cams have so many focus points. It's true that focus/recompose does introduce a slight error; but it's negligible unless you're doing macro work. – user4894 Jul 17 '14 at 23:43
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    I think the flagged duplicates address why you would manually select an alternate focus point - not the middle one, where this questions is about letting the camera use its many focus points and do the selection? – MikeW Jul 17 '14 at 23:49
  • On Ken Rockwell and entertainment vs. facts, see photo.stackexchange.com/questions/10980/… – mattdm Jul 25 '14 at 22:39
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Modern auto-focus systems are designed to accommodate a wide range of shooting applications that require different ways of using the auto-focus system. Which way is the best for you depends on several factors: Your subject matter, your skill level, and which setup produces the most consistent and accurate results for the particular camera/lens combination you are using.

Just because a camera includes 9/19/39/57/61 focus points doesn't mean you or anyone else should always use all of them. After all, only one distance from the camera can be in focus at any one time. What should guide your decision is to select the settings that allow you to capture the particular subject you are shooting with the most accurate and consistent (from shot-to-shot) results.

If you are shooting a static subject that is not in the middle of the frame, you might be best served by using a single focus point that falls over the part of the frame you want to be in focus when the image is already composed. If you are shooting moving targets in fast action you probably want to use multiple points with a form of AF-C/Servo focusing mode to allow your camera to track the subjects as they move about the frame.

If you are confident in you ability to act quickly and decisively and are intimately familiar with your camera's controls by touch (so that you can change settings without removing your eye from the viewfinder) you may want to use single point and control which point is active for each shot as you shoot.

In general the more you understand how your camera's focus system works and the more you learn how to control it the more you can control what the focus system locks onto instead of depending on an automatic mode that may or may not guess correctly at what you want to be in focus.

Focusing and recomposing works well for some types of photos, but not so well for others. The danger with focusing and then recomposing is that the subject distance to the lens' entrance pupil may change slightly and result in slightly missed focusing, especially when using wide apertures that result in narrow depth of field. Knowing which way and how much to move the focus ring to compensate in such a situation back in the manual focus days when most cameras were easier to focus at the center of the frame was a valuable skill gained by practice and experience.

For why the number of focus points is not as important as the accuracy/consistency of focus points please see What is the effect of the number of cross-type focus points on sharp focus?

3

Don't feel bad about using a single focus point in the center. That's what I do too most of the time. Often enough the main point of a picture doesn't appear in the center, and the automatic system guesses wrong what it should focus on. If find the point, auto-focus and freeze, reframe, and click sequence works pretty well most of the time.

Don't be shy about flipping to manual focus in difficult circumstances. Sometimes it can be easier than to get the auto-focus system to do what you want.

On the whole though, I appreciate the camera being able to focus for me more quickly than I can.

There is one exception where I find multi-point focusing really useful, which is when photographing fast action, like a sporting event. There the subject is usually the closest thing in the frame, and you need the speed of the camera doing the focusing to make the shot possible at all.

1

Just because you have several focus points doesn't mean you need to use them all simultaneously. This, and other features, are just tools to assist you in taking the picture; use it how you feel best.

Personally, I rarely use anything but the center point and never use all points together.

Keep in mind anyone can say anything on the internet and some people may be better sources of information than others. While I may not have much of a reputation as a good source of information, Ken Rockwell tends to have a bit of a reputation as a bad source of information. By itself it doesn't mean he's right or wrong, but think critically of what people say and utilize multiple sources when possible.

1

The purpose of the multiple focus points is that the camera is supposed to do the work for you. The idea is that you shouldn't have to point at the item that should be in focus, the camera would figure that out automatically.

As with most automatic systems, it doesn't work all the time. More focus points means that it gets better, but never perfect. That means that you still have to check which focus point the camera chose to use, as a bad choise would most likely make the image unusable. If the camera chose badly, you have to change the focus settings and start over, which means that you might miss the moment.

It's a matter of weighing the convenience most of the times against the inconvenience the times when it fails, and what you feel works best for you.

Just as you, I use a single focus point. Be careful about when the exposure measuring happens, though. If possible you would want to use one button only for focusing, and having the exposure measuring happen when you have composed the image. If the exposure is measured when you focus, it can be affected by things that are in view then but not in the final image.

1

Preferences vary.
I personally find it far more convenient AND more likely to achieve what I want in the time available by using just the centre focus point in most cases.

As people have noted, recomposing photos by focusing on an off centre point and then holding the focus setting and moving the camera can lead to focusing errors when large apertures are used such that depth of field is small.

In such cases you may wish to

  • use multiple focus points or

  • move the single focus point or

  • learn how to compensate.

I almost always do the latter and almost never the former.
Rather than refocusing manually it may be easier to move slightly in or out to maintain distance.
This takes practice, as do most other things that allow you to come to use the camera intuitively without conscious thought. If you value becoming one with your camera, as it were, then such practice is a labour of love :-).

Some cameras have features which assist you in fine tuning or checking focus.
eg some Sony SLT cameras have 'focus peaking' which will highlight in-focus image areas when the camera is in manual focus mode. By using af and then holding the MF/AF button you can flip the camera into MF and instantly view focused areas. You can also use this to either manually adjust focus or use foot-focus( like foot zoom but different) to fine tune focus if needed.
Whether a given camera has useful features such as this is manufacturer and model dependent.

0

Using the center focus point will assuredly always give you a nice clean and crisp focus. I have found with many cameras that many times, because of the curve of the lens, the optimal focus point is always the center one.

If you are looking for perfect clear focus, use the center focus point and then recompose your shot if needed.

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