I'm sure you will all agree in me saying, nothing ruins a photograph more than an unintentional blurry and/or soft image. The autofocus feature is an incredible tool but it is vital for you to understand your focus modes.
It is also good to know that as useful as autofocus is, sometimes the camera gets it wrong. Remember, your camera is not thinking like you are and could focus on the wrong subject. Additionally, there are also situations where the autofocus just can’t cut it. This is usually in areas with very low light or when your subject is hidden behind an obstructing foreground as seen below;
But for the most part, and the fantastic thing about autofocus on today’s cameras, is that you can let the camera do all the work to get render tack sharp images. In saying this, purchasing a new camera and falling victim to the pick up and shoot method; well, this will not always get you these desired results. It's crucial for you to first understand your focus modes.
So let me now share the three primary focus modes with you which will give you the flexibility in order to capture exactly what you want.
- Single shot focus
- Continuous focus
- Automatic focus
- Manual focus
This is referred to as AI Servo AF (Canon) and/or AF-C (Nikon). This mode is most useful for when you want to continuously focus on a moving subject. As soon as you begin to depress the assigned focus button; this may be your back button or your shutter release, the camera goes into action and begins to focus. In this mode, the camera detects the subject’s movements and refocuses accordingly to keep the moving subject in focus. This will only be the case if you continue to hold down your assigned focus button and keep your focal point on your subject.
Even though this mode uses a lot of battery power due to the fact that it is continuously focusing and refocusing, I spend 98% of my time photographing in this mode. Not only does it save me time not having to change between the various modes but I can also use this mode as a single shot focus mode because I make use of my back button to activate my autofocus.
You may be wondering, what is back button focus?
This setting basically separates the focus and shutter release functions, moving the former to the AF-On button at the rear of the camera.
This button is operated with your thumb and will quickly feel natural to you with a little bit of practice. Now, when AF-On is depressed, the camera will focus. Half pressing the shutter release button will not activate the autofocus and so the way I use this setup as one shot focus is that I simply focus on my static subject, release the back AF-On button, recompose and take my image.
One Shot Focus
One-Shot AF (Canon) and AF-S (Nikon), represent single-focus capability.
In this mode, when you depress your assigned focus button, the camera focuses on the subject just once and there’s no continuous adjustment. This means that if you acquire focus keeping your focus button depressed and your subject starts to move, your autofocus will not refocus. You'll have to actively remove your finger from the focus button and depress it again to regain focus.
This mode does save battery power but I am sure after reading the above, you can see that this can become a bit of a hassle.
Automatic Auto Focus
Referred to as AI Focus AF (Canon)/AF-A (Nikon), this is Automatic Autofocus.
This is a relatively new feature which has turned out to be quite useful. In this mode, the camera’s focusing computer jumps back and forth between AF-C and AF-S (Nikon)/One-Shot AF and AI Servo AF (Canon) depending on the situation. For example, if your subject is not moving, your camera will function with its One-Shot AF mode. As soon as the subject starts moving, your camera will pick this up and automatically switch over to continuous focus.
This is the default autofocus mode on cameras that have this feature but is something I personally do not have much faith in. Just imagine a sudden movement (lions suddenly attack each other) and your camera does not react in time in its switch from One-Shot to Continuous. You'd have missed out on some incredible imagery. You might be the one sitting with those soft blurry action images while everyone else that were ready for action on continuous focus have the tack sharp hero images.
Always remember, you never know what’s going to happen next or what’s going to catch your eye, so it’s useful to have the camera make the quickest possible focus adjustments.
In my books, the choice between the two is a no brainer. This choice is now yours and having read this, you should understand your focus modes a bit better and I do hope this is helping you.
Manual Focusing Mode
Manually focusing is pretty much self explanatory. You will have to manually find focus by controlling your focus ring on your lens. Prior to doing this you will have to change your AF setting on your lens to MF (Manual Focus) unless you make use of back button focus.
Manually focusing the camera is perhaps the most frustrating barrier between good and great photography. This focusing method will obviously work best in certain genres more so than in others. See, to achieve absolute perfect focus requires using the distance measurements on the lens barrel;
and even perhaps measuring the distance from the lens to the subject with a tape measure; high-end photographers shoot products this way, and so do fine art photographers who are using medium format cameras. Now making use of a tape measure will not be possible in any wildlife scene for the multiple obvious reasons.
When photographing wildlife, you may come across a scene; as seen in the first image in this blog, where manual focus will be your go to tool and you will have to rely on your internal sense of sharpness and know the critical focus zone that you have at the specified aperture.
There is a diopter adjustment on most DSLRs (it’s right next to the viewfinder) that lets you make fine adjustments to the focusing capacity based upon any irregularities in your eyesight.
I do hope that after reading this blog, you now understand your focus modes a bit better. Please feel free to leave me any questions in the comments below.
Until next time;