With the introduction of technology into our lives, it is now possible to see the blessings of technology in every area of ​​our lives. Autofocus technology is one of them. So what is autofocus?

Autofocus We call the auto focus to make the subject or object clear by moving it through a series of small motion motors on the lens of our camera or lens. While doing this, the micromotors on our machine make this focus thanks to a software. When we press the shutter button of our camera halfway, our camera focuses automatically.

what is auto focus


Although it has a complicated technology, we will not enter the technology part of the business. We do not look at how this car is produced or what technology is used while driving.

Simply, when we were young, we all tried to read a book using a magnifying glass. What were we doing there to make the articles readable? We were making the articles readable by moving the magnifier up and down. This is where autofocus is done with technology.

what is auto focus


If we think of the our lens as a magnifying glass, we can liken our hand to micromotor. These micromotors focus by moving the lens elements. When we press the shutter button halfway down, either a sound appears or light flashes, it tells us that we are focusing. In manual focusing, we do this by looking carefully at the LCD screen or viewfinder by turning the focus ring.

what is auto focus


Well, we did not move our hand and read the text when we saw how we decided that the focus was made, that the writing became readable, and when we thought that the writing became readable with our brain. The software that exists on cameras does this for us. This technology is called autofocus.

This system is found in fully electronic cameras. The sharpness adjustment is made automatically by the movement of the lens until the image to be captured is the most prominent / sharp in the microprism in the middle of the viewfinder, and the lens stops automatically when it comes to the clearest position. Almost all new types of machines have multiple sharpness selection settings. When one of the small squares with black lines (such as 3,5,7) whose number varies from machine to machine, is selected by matching the point to be clarified, the sharpness adjustment is automatically made to that area0. If one of these sharpness squares is not selected, all squares are activated automatically and usually focus in the area near the front.

Advanced cameras have multiple focus programs. Knowing these programs and preferring them on the spot allows you to focus accurately when working in automatic adjustment. These are usually shown on machines with the name One Shot AF, Al Servo AF, Al Focus AF.

what is auto focus

In some cases, our camera cannot autofocus, and for such cases, our camera has an autofocus button on the lens, and it is possible to manually focus on the lens by taking it in manual mode.

Autofocus on cameras is one of many automated features that make working together as easy as possible. The more important the correct exposure is for the photo, the more accurate the focus is. If the focus focuses on another subject behind or in front of your subject, rather than the subject you are trying to shoot, the photo will no longer be available.

What is the focus?
—The point or area used by the focusing system when focusing. When we press the shutter button halfway, both the focus is made and the spots that light up red when the focus is made show us the focus point.

what is auto focus

—Each DSLR leaves the decision to choose which of these focus points to use. The user can choose all if he wants, or only one. Some machines also allow to select them in groups.

—When do we choose all the points?

When we want to activate all the focusing points of the machine.

—When do we choose a single point?

When we want to increase the focusing speed, that is, if we place our subject at one of these focal points, we choose it. Thus, the system concentrates on the region where that point is.

auto focus

In the photo above, the focal point was selected as a single point and it was focused on the object in front and provided focus. Note that the object is not clear.

auto focus

In the photo above, the focal point has been selected as a single point and it was focused on the object on the back to provide focus. This time you see that the object in front is not clear.

What we see here clearly is that by changing the focus point, we can use our depth of field well, and we can get different photos by deciding which area is clear and which area is blurred.

Autofocus (AF) Modes

auto focus portrait

-Single Servo: It is the AF mode that should be used in subjects such as portrait and landscape where the subject is not moving. It is a program suitable for still and slow moving objects. When the shutter-release button is pressed halfway, the lens focuses on the subject set with the active focus point. Focus is fixed as long as the shutter release button is pressed halfway. If the lens fails to focus on the subject, the “One Shot AF” shutter will not move.

auto focus modesContinuous-servo: Developed to track moving objects. If you gonna shoot fast moving objects it is the choice that you need. When the shutter-release button is pressed halfway, the lens focuses on the subject but is not fixed. Instead, the lens continues to follow the subject and changes the focus point as the distance between the camera and the subject changes. Even if the object is not clear, the shutter can be pressed at any time.

auto focus

– Auto Servo AF: It is the AF mode that switches between single-servo and continuous-servo depending on the situation. For example, you are in a car race, cars stop at the starting point and then take action. If the camera is in this mode, it will perform single-servo first, then it will switch to continuous-servo when the cars move. This program is basically a “Single Shot” program, but if the camera detects an object that moves fast, it automatically switches to the “Auto Servo AF” program. On some cameras, the “Al Servo AF” program can only be switched via “Al Focus AF”.

Each brand has different settings and names. Each brand has different settings and names.
– As the AF system can make mistakes like any electronic / mechanical system, it may be necessary to know the operation of the system and intervene in cases where it fails. In such cases, manual focus is used.

What is MF (Manual Focus)?

  • If we focus manually, this is called manual.

  • The hardest part of using MF is to focus accurately. If you are using your AF lens as a MF, your focus is still not very difficult as the focus lights will still be active, so wait for the light / sound signal at the time of focusing. Then take your shot.

—You see the focus settings buttons on the Lens in the photo below. There are two types, A and M in general.

what is auto focus

—A is Auto mode and automatically focuses if you tap the shutter button slightly

—M is Manual mode and you need to turn the focus ring manually to focus, the focus feature is disabled by pressing the Shutter button.

If we don’t want blurry photos in our archive, if we want clear photos, we should be very meticulous when focusing. Especially when we came home and examined our photographs, we want to see very beautiful frames, but when we face with the problem of clarity in these frames, we get frustrated. The more important the exposure in the photo, the more important the clarity. So we have to be very careful.

If you need more ideas, technique, tips and tutorials you can check our Photography page here.

May your light be bright. Stay healthy.

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Digital photography ideas, tips, techniques and tutorials for camera owners of all levels.