E09 establishing focus

Camera Basics
Establishing Focus

The one thing that enables the photographer to convey his photographic intent to
the viewer is establishing the focus. What are the secrets to establishing the best
focus? Let’s find out more about the special features of autofocus (AF) and
manual focus (MF).


There are two ways of establishing focus: Using the camera autofocus system, or
manual selection and adjustment
Points-to-note
- “AF” refers to “autofocus”. This is when the camera tunes itself to establish the
best focus when taking a photo.
- “MF” refers to “manual focus”. This is when the photographer adjusts the focus
manually to establish the focus.

Establishing focus is a basic skill in photo taking. There are two ways to establish
focus. The first is through autofocus (AF) operation, where the camera


automatically establishes focus. The second is through manual focus (MF)
operation, where the photographer adjusts the focus by hand.
In most shooting scenes, AF can do a good job of establishing focus. When
shooting photos in AF mode, all it takes is to simply press the shutter button
lightly (“half-press” the shutter button) to activate the AF and AE functions,and the
camera takes care of the rest. Once focus has been established, press the shutter
button down (“full-press” the shutter button).

This is what AF is all about—shooting good pictures with very simple operations.
For more control over the composition of your photos, you can pre -select the

active AF area (or AF point) during autofocus operations.

But AF is not perfect and there is a limit to what it can do. Sometimes, the subject
or the scene makes it difficult or even impossible to establish focus. W hen up
against these situations, make good use of MF. By looking through the viewfinder
and turning the focusing ring with our hands, we can establish the focus just as


well too. Since we can enlarge the focus area when in Live View mode, it is
possible to establish focus more precisely.

AF

EOS 80D/ EF-S18-135mm f/3.5-5.6 IS USM/ FL: 124mm (198mm equivalent)/
Aperture-priority AE (f/5.6, 1/200 sec, EV -0.3)/ ISO 3200/ W B: Auto

Benefits: Can establish focus quickly
Drawbacks: Some subjects and scenes are not ideal for establishing focus
Since AF establishes focus quickly, it is very convenient in most situations. But
sometimes there are subjects or scenes that are not ideal for establishing focus. It
is wise to switch to MF when the situation calls for it.


MF

EOS 6D/ EF50mm f/1.8 STM/ FL: 50mm/ Aperture-priority AE (f/3.5, 1/40 sec, EV0.7)/ ISO 100/ W B: Auto

Benefits: Can observe the subject with our own eyes as we establish focus
Drawbacks: Takes more time before we can actually shoot
As we can observe the subject while we adjust the focu s in MF, it makes it

possible to establish a more precise focus. Nevertheless, the whole process takes
more time. W e have to spend time establishing focus before we can go into the
actual shooting.


When the subject or the scene is not right for AF, switch to MF

When the subject happens to be in a very dark place, when it is a low contrast
scene or when it is a scene where the subject is sometimes blocked by nearer
objects (such as when photographing animals in a cage), AF cannot establish
focus easily. W hen faced with these situations, switch the focus switch on your
lens from AF to MF. By switching to MF, we can establish focus by adjusting the
focusing ring by hand.


Related concept 1: AF Lock

Know the “AF Lock” shooting technique, this is a way o f taking photos in AF mode
where the focus is first established before fine -tuning the composition of the
photo.

First, manually select the active AF point. Choose the AF area/point that is located
closest to the subject of interest in your ideal compositi on. Although AF Lock can
be applied with any AF area mode, in general, the centre AF point should have the
highest precision and is the best choice when dealing with dark scenes.

Next, align the selected AF point with any part of your intended subject, and press
the shutter halfway. When the camera has established focus, leave the button half
pressed and fine tune the composition. When that is done, press down fully and
complete the shoot.

If you can master the technique of AF Lock, you can place the primar y subject
(that you established focus on) anywhere within the image frame —not just in the
centre.


Selecting the active AF points (*on the EOS 760D)

Press the AF point selection button (circled in red) to display the screen for
Single-point AF (Manual selection).
*If another mode is displayed, change the mode using the AF area selection
button.


The Single-point AF (Manual selection) screen allows you to choose the active AF
point.

Next, use the Main Dial, the Quick Control Dial or the touchscree n to select your
preferred AF point. Here, the point to the left of the centre AF point is selected.

Related concept 2: The back-button AF technique

Normally, when the shutter button is half pressed, AF (focus establishment) and
AE (exposure determination) are activated simultaneously. But by customizing the
camera, we can get AF and AE to operate independently. You do this by operating
the AF with the AF-ON button in the back of the camera (or the AE lock button),
and the AE with the shutter button. W e cal l this technique the back-button AF
technique.

The advantage of this technique is that when the camera is in AF Lock mode,
there is no need to keep the shutter button half pressed. Once focus is established
with the AF-On button, the point of focus is fixe d, and won’t change even when
you remove your finger from the button.

With this technique, you can take as many photos as you like with different scenes
but the same composition.

The back-button AF technique

You can customize your camera to carry out f ocus establishment and exposure
determination independently of each other.


1. Establish focus in AF-ON mode
2. Press the shutter button to release the shutter
Use the AF-ON button (or AE Lock button) to establish the focus, then release the
shutter with the shutter button. W hen you want to reestablish the focus, all you
have to do is to press AF-ON again.


EOS 5D Mark III/ EF24-70mm f/2.8L II USM/ FL: 70mm/ Aperture-priority AE (f/2.8,
1/400 sec, EV+0.6)/ ISO 100/ W B: Daylight

I established focus on a cat that appeared all of a sudden with the back -button AF
technique, engaged AF Lock and then fine -tuned the scene. I managed to try out
different compositions continuously with the help of the technique