Focus is as essential in photography as it is in life. Focus lends sharpness to your pictures. If you fail to pay attention to focus, you end up with blurred pictures. It’s important to understand the basics of focus in photography to start right and avoid falling into bad photographic habits.
Let’s Start with Some Specifics
You already know what focus is, right? At least you have heard the term and used it earlier. As in life, being focused in photography means concentrating on the most important part.
Plane of Focus
A plane is a two-dimensional area such as the surface of a piece of paper. When you focus your camera, you are actually creating a plane of focus. You can visualize a plane of focus as a flat surface. If you drop a curtain on the point of focus, all objects touching this curtain will be on the plane of focus.
What Does It Mean for My Camera?
When you focus, you are adjusting your camera lens to make it see the things on the plane of focus most clearly. All objects lying nearer or further will be out of focus to varying degrees. Since your camera lens sees the plane of focus most clearly, objects intersecting this plane appear the sharpest in your photo.
How is Focusing Achieved?
Focusing is the process of determining the plane of focus. Cameras achieve this by moving the lens forward or backward. Changing the plane of focus helps in making the object of your photo appear sharper to the camera.
Let’s Take a Deeper Look
There are several details related to focus that you need to understand to gain expertise. Modern cameras offer a lot of options that you should know and be able to manipulate for the best results.
Can Focus be Automated?
Yes. Most cameras not only allow automating focus but also give you several options that let you decide how it happens. If your camera doesn’t have an autofocus facility or if you choose not to use it, you can always use the manual mode.
Does Manual Focus Need a Great Amount of Skill or Precision?
In the manual mode, you turn a knob to change the focus. You do need some skill but not of the physical variety. You need to be able to achieve the correct focus using your own judgment. You may not get the same precision as an automatic focus. You can see the effect of autofocus in the picture below.
How Does Automatic Focus Work?
When you are using automatic focus, a motor inside the camera does the job for you. You don’t need to turn any knob manually.
Should I Use Manual or Automatic Focus?
If your camera doesn’t have an automatic focus facility, there is obviously no choice. Like photographers of a bygone era, you will need to use manual focus. Most modern cameras come with an autofocus facility you can use. Even if your camera has an autofocus option, you may not always want to use it.
Why Can’t I Use Autofocus in All Situations?
There may be situations like poor lighting conditions that autofocus might be unable to handle. In such cases, you might use manual focus to get better results. If you are taking many pictures at a time with the same focus, manual focus would enable you to lock your focus and use them for all the shots. As you can see, there are situations in which manual focus might be preferable.
Choose Your Lens with Care if You Want Autofocus
Some of the older models of cameras may not have an autofocus motor in them. Autofocus lenses also may not come with such a motor in all cases. So, you need to choose your lenses with care if you are planning to use autofocus with an older camera that doesn’t come with a motor.
Other Things You Should Know About Autofocus
We’ve seen that autofocus provides options and requires you to make choices. Let’s look at some of the options and how you can choose from them.
Put the Detective in Your Camera to Work!
Your camera will have different types of detection for setting the autofocus. That is one of the choices you will need to make. There are two types of detection; each useful in its own way. You should know which one to use and when.
This is one of the two types of detection available to you, with the other being contrast detection. Phase detection is faster but also prone to more errors. That’s natural because it works with fewer details.
When Should You Use Phase Detection?
When capturing pictures of moving objects, speed is essential. You can compromise on the precision of focus, but you need fast adjustments. Phase detection is useful for moving objects. To minimize errors, you can use the calibration facility, if it is available in your camera.
When you have all the time in the world and are looking for greater precision, you would choose contrast detection. What you get is a more detailed analysis and precise pictures. The trade-off is the time it takes to process that information.
When Should You Use Contrast Detection?
Because of the time it takes, contrast detection isn’t good for tracking a moving object. Your object might have moved away by the time your camera figures out the best combinations. For still pictures and portraits, however, this is your ideal choice.
Setting the Detection Isn’t Rocket Science—You Can Do It Easily
Going through all of that has probably left you wondering to set one or the other of the detection types. There’s no need to worry. It happens automatically, depending upon your choice of view mode. If you choose the viewfinder for autofocus, your camera will set it to phase detection. That is true on most cameras. If you choose a live view, your camera sets it to contrast detection.
What If I Have a Mirrorless Camera?
DSLR (Digital Single Lens Reflex) cameras house a mirror that reflects the light to the viewfinder, which is where you see the object you are shooting. This mirror moves to allow light in automatically to a sensor when you use the screen for viewing. Therefore, the view mode that you choose determines whether the mirror is used or not. That’s fine as it goes. But there are cameras that do not use SLR or mirrors. What happens then? In that case, you don’t have a choice. Such cameras have a single composite system that works in both cases.
Remember: Focus Is About Getting to the Plane of Your Object
Whichever detection system you choose, your aim is to focus on the object by getting your lens to align with the plane in which your object lies. You should determine which of these two systems will help you do that.
Why Should You Bother About Which Detection System to Choose?
That’s a good question because whichever detection system you use, your camera will set the focus on the plane of your choice. The difference is in the details and the speed. Phase detection will do it faster but with fewer details. Contrast detection will analyze it in greater depth but take a little more time. So, you don’t have to worry about getting the focus in either case. The choice depends, as we have seen, on the type of picture.
There’s More to It - A Look at Focus Mode
Now that we know all about detection, it’s time to move on to the next important issue, which is the focus mode. These can be either continuous or single focus.
Use Single Focus for Objects That Aren’t Moving
You will use single focus on a stationary object. Single focus locks the focus on an object and keeps it there. That will give you the time and opportunity to adjust your composition or make other changes if you want to. In this mode, you can change the focus again only by releasing the button and clicking again.
If You Are Trying to Capture A Moving Object, Continuous Focus Should Be Your Choice
With continuous focus, the camera changes the focus continuously to keep up with the movement of the object. You get into this mode by keeping the focus button half-pressed.
Can My Camera Detect the Situation and Decide the Mode?
Some cameras can. It depends on the model that you have. If your camera has this option, it will select the right mode depending on the situation. Even if your camera has such an option, it’s still helpful to understand this function. For one thing, your camera might make a mistake at times, and you should be aware of such mistakes and know how to correct them.
Here’s How You Can Decide Which Mode to Choose
Let’s get down to brass tacks. To make matters simple, one rule of thumb is that if you are taking landscape photographs of things like buildings, you can opt for single focus. For most other situations, and especially for moving objects, continuous focus should be your choice.
Look For the AF-On Button. It Can Make Life Easier
We saw that for continuous focus, you need to keep the focus button half-pressed. Many cameras provide a separate button – the AF ON button. By pressing this, you tell the camera that continuous focus is on. In that case, there’s no need to keep the button half-pressed.
It’s More Than Just a Convenience
The AF-ON button could be more than just a convenient way of maintaining continuous focus. You will find it invaluable in many situations.
You Can Maintain the Same Focus Across Different Photos
You can do this by keeping the AF-ON button pressed until you’ve finished all the photos.
You Can Recompose an Existing Shot
Remember that composition is about arranging the objects. Let’s say you find that they are not to your liking and you want to rearrange them. You just leave the AF-ON button pressed while you make the changes. After recomposing, you can come back and click the photo without bothering about the focus once again.
You Can Wait for Events to Happen After Fixing the Focus
You might find situations in which you have to wait for something to happen. Say you want to click a person coming out of a building. You can fix the focus and wait for the person to appear.
The Focus Area Mode – A Critical Decision You Must Make
We’ve talked about automatic decisions your camera can make. You have to give some information to your camera for making these decisions. It all boils down to selecting the area of focus and the number of focus points. You can choose a large or small area, and you can choose more or fewer points within that area. You can see an example of this in the figure shown below.
You can see that there are fewer points in the figure to the left. You can also see the differences in the areas covered.
How Do I Tell the Camera About the Focus Area I Choose
If your camera has an autofocus facility, it will also have a choice of mapping from which you can choose. Once you do that, your camera will know the kind of autofocus strategy you are looking for.
Why Is That a Critical Decision?
You are going to depend on your camera to make the best decisions for autofocus to work most effectively. These decisions will depend on what you tell your camera about the focus area.
There’s Just One More Thing …
Deciding the area isn’t enough. You have to tell the camera which points to focus on and how. You can focus on a single point or multiple points. You can make it dynamic or static, i.e., your object can be moving or stationary. Let’s look at how all these combinations work.
Single Point Focus
You select one focus point, and the camera follows it. This is ideal for capturing stationary objects. Not that it won’t work with moving objects, but it may not be effective for objects that move fast. For most moving objects, you will do well to select one of the other modes, which I discuss below.
In this case, also, you choose a single focus point but allow it to move within the focus area. Your camera tracks the focus point when it moves into any of the focus points that you specify. You’ll find this a good choice for moving objects, for example, in wildlife photography.
Here you specify multiple focus points. The camera keeps track of the object as it moves across these points. How is it different from dynamic focus? You don’t have to pan your camera in this case so that the object is kept close to the focus point. The camera takes care of that. This is also a good choice for moving objects, but for fast-moving objects, you may not find it efficient enough.
In this case, you designate more than one focus point. The usual number is five. Your camera will follow all these points and focuses on the point to which the object comes closest. You will find this useful for fast-moving and less predictable situations such as a bird in flight. You can get a feel of this from the picture shown below.
Can My Camera Not Decide the Focus Area for Me?
It can, in most cases. Most cameras include an auto area selection mode. But you may not find it very useful. It works by choosing the object that is nearest. That might not be the focus that you want. That’s why it might not be a good idea to leave this decision to the auto area mode of the camera.
A Word of Caution
I have described the features and options commonly available in most cameras. Your camera may not have all of these. Alternately, it may have some of these but call them different names. You should familiarize yourself with your camera and choose the options accordingly. Your camera will still have the features described above. It’s only a matter of understanding how much of it is there and by what it is called.
Experience Is Your Best Teacher
You might find all of this a bit overwhelming. There’s no need to worry. You will find your way as you go along. You will understand your preferences and what works best for you.
Here’s A Tip on How to Get the Right Focus
You focus your camera on a point or a small area, but the object you are capturing is usually larger. Sometimes, you might be confused about which point to focus on. Let’s say you are capturing a bust of a friend. Which part of the face would you focus on? Experience is your best guide, but as a general rule, you can focus on the central or most important point. For example, the eyes could be the object of focus.
Focus As an Art
Many times, you will find that rather than go by a rigid or preconceived rule, the situation can guide you best. In many cases, there is no right or wrong focus point. You may decide on them with an eye on aesthetics or conveying a particular impression. The best way is to trust your instinct and become creative with your camera.
A Final Tip – You Can Get Multiple Focus Points Using Focus Stacking
Focus stacking is a technique that allows you to capture multiple pictures of the same object with different focus points. You can then combine the focus points of each of these into a separate photo, and what have you got? A photo with the sharpest focus over a broad area. We enjoyed sharing our knowledge with you, and we hope you enjoyed and found it useful too.