One of the most important thing in a good photo is the focus. Sometime it can be as easy as pointing the camera to the object you want to focus, other times it just does not work. There are different camera focusing techniques and each one can help to either blur part of your photo or have a full sharp image.
The focusing in the landscape photography is relatively easy as most of the people or objects are still. In action or sport photography it may be much more challenging.
The manual focus is very simple to understand because you need just to focus your lens on your subject. Easy said more complicated to accomplish. I usually use a Nikon D600 and focusing with the view finder is not that easy.
I tried a couple of high-end mirrorless, a Panasonic GX8 and a FujiFilm X-Pro2. The manual focus with the digital view finder works much better as it zooms in to the details. Even better, the area in focus has a blue halo, which helps to identify the focus distance
If the Manual technique seems too challenging, especially with travel photography, than Autofocus comes to help, however you need to know few things
Auto focusing functionality
As a start the AF functionality seems pretty straight forward: put your camera in AF mode, half-press the shutter release button and watch as the subject snaps into sharp focus in the viewfinder.
This may be perfectly adequate for some situations, but modern DSLRs offer many more modes and settings that allow their AF systems to be fine-tuned to a range of different shooting situations.
These modes and settings work in a variety of different ways and, unless you know which to select for a particular type of subject or shooting scenario, you probably won’t be using your camera’s AF to its full potential.
The autofocus mode determines how a camera acquires and maintains focus.
There are three principal modes – auto-servo, single servo, continuous servo.
AF-A Auto-Servo mode
It makes an automated selection of either single or continuous mode, depending on whether the AF system determines that the subjects stationary or moving.
I would probably not suggest this mode, unless at the very beginning when you struggle with all the settings in the camera
AF-S Single-Servo mode
In single servo mode the AF system will focus the lens on whatever the selected AF point(s) is covering, and lock the focus distance the instant that focus is acquired.
Typically, in this mode the shutter release is disabled until the lens has been focused, and no focus tracking is performed, so it’s best used for static subjects.
Provided you keep the shutter release button half-depressed the focus distance will remain fixed, which enables the picture to be recomposed, as the subject doesn’t have to be covered by an AF point.
However, you must always make sure the camera-to-subject distance doesn’t change before you take the shot. In this way you will have a sharp image. If it does you’ ll have to refocus.
Almost static crowd in Penang , Malaysia. Single-Servo AF was used as no real moving subjects
AF-C Continuous-Servo mode
In this case the AF system focuses continuously on the area covered by the selected AF point(s), monitoring the focus distance constantly, even after focus has been accomplished, so if the camera-to-subject distance alters, the focus is adjusted accordingly.
It makes this mode perfect for moving subjects, because not only will the AF system alter the focus to follow the subject, but it also allows the shutter to be released at any time, even if the subject isn’t in focus as shutter release is pressed.
Understandably you might assume this would result in an out-of-focus picture, but in continuous servo mode as soon as the AF system detects a moving subject it activates a predictive focus-tracking feature.
This uses info from the AF system to adjust the point of focus to account for the change in the subject(s) position during the split-second delay between the camera’s reflex mirror being lifted and the shutter opening, even if you fire a rapid sequence of shots.
Due to the constant adjustment of the focus in this mode, if you want to compose a shot in which none of the AF points cover the subject, it will be necessary to lock the focus distance by pressing an AF lock button (AF-L)
The CyclingTips Amys Wall. I followed this cycling race using the continuous-servo mode AF-C as the subjects were obviously constantly moving.
When using AF-C usually you focus on the main subject of your composition. I suggest a to use the lowest value in aperture you have (F/1.8 to F/4). In this way your subject will be sharp and the background blurred
Why Auto Focusing does not always work
In order for any AF system to function properly, two conditions must be satisfied.
- First, there must be some contrast in the area of the subject on which you want the camera to focus. Trying to get the camera to focus on an area of plain, continuous tone won’t work.
- The second condition requires that the AF system receives a minimum threshold amount of light for the autofocus to function properly. So, in certain low light conditions autofocus can be unreliable or may not work at all.
When in AF the camera will always try to focus and, if one of the two condition above applies, it will cause the AF to hunt; as the focus is driven back and forth without locking on the subject.
Try, for example, to AF in the night. You will clearly hear the lens motor trying to focus till it gives up. You will experience the same result if you try to focus on an area without contrast, for example a full black sheet (just as an exercise).
The accuracy of autofocus is determined in part by the number, distribution and type of AF points your camera has. An entry-level DSLR may have as few as three AF points, while some professional models have more than 60.
Which AF-Mode do I suggest?
In most of my travel photography I use the single servo mode (AF-S). This covers landscape photography and some almost static subjects like you may encounter in the markets on in the streets.
There are however cases where AF-C is essential. This is mostly when you have some action in your travel photography. This could be some interesting local horse races or kitesurfing/windsurfing at the beach or any other sport that has continuous, and sometime unpredictable, movement.
I was driving my car in Mauritius when I saw an improvised motorbike race organised in an run-down parking area. Definitely a great subject for some unusual travel photography. I parked the car and I started my visit inside the track. I began shooting using AF-C mode to focus on the drivers
Auto focus areas
It is now time to introduce another important concept, the Auto Focus Areas, and how they determine which AF point(s) will be used.
Although the options differ slightly, based on the camera brand, there are three main groups:
- single point
- multiple point
- auto point
I usually shoot with a Nikon and most of the vocabulary is Nikon related, however, when possible, I try to introduce also Canon wording.
Single point mode
Single point Focus in Nikon
In single point mode, known as Manual AF point by Canon and Single-point AF-Area mode by Nikon, only the individual AF point you select is used for focusing. The camera has no influence on the chosen AF point. Selecting the central AF point may seem the obvious choice, as it’s almost always a cross-type and frequently the quickest and most reliable.
However, as far as composition is concerned it’s often better to avoid placing the subject in the middle of the frame. To shoot a picture where the subject is off-centre, you can position the centre AF point over the subject, acquire and lock focus before recomposing or, alternatively, select the AF point that’s closest to the area you want to focus on.
Single point focus on the boy. This was part of a commercial photography assignment and models were still.
Multiple point mode
9-point Dynamic Area Focus in Nikon
In the Nikon world this is known as Dynamic-area AF mode
This is a variation on the single point mode, since the AF system will use the individual AF point selected initially by the photographer.
However, if the subject leaves the area covered by this AF point briefly, the AF system will immediately evaluate information from a pre-selected number of surrounding AF points in an effort to maintain focus on the moving object or person.
The number of focus points that will be used to support the selected AF point varies depending on the particular camera model.
Multiple point mode is a good choice when photographing a moving subject. However, there are a couple of things to consider when deciding on how many AF points will be used to support the selected AF point.
- the area covered by the group of supporting AF points should not extend too far beyond the edges of the subject, otherwise there is a real risk the AF system will focus elsewhere, usually on the background.
- selecting as few AF points as possible in the supporting group will reduce the amount of data the camera has to process, and thereby increase the speed and accuracy of focus.
Nowadays I mainly do travel photography however, from time to time, I have assignments in the cycling world (I am a passionate road cyclist myself)
Bicycle riders move constantly obviously. When I was making photos of single riders I was using a 9-point dynamic-area AF however with groups of riders I was selecting a 21-point dynamic-area.
Dynamic-area Auto Focus – I pointed the focus on the rider which was cycling in a predictable way towards me. The dynamic-area together with the continuous servo option worked perfect for a moving “object”
Auto point mode
Auto Area Focus in Nikon
In the Nikon world this is known as Auto-area AF mode
Auto point mode can be considered as a point-and-shoot Auto Focus solution. As its name implies, it’s fully automated. The technology that works behind the scenes is very complex.
All you need to be concerned with, though, is remembering that in this mode the AF system is prioritised to identify skin tones, and the pattern formed by the eyes, nose, and mouth of a human face.
If the camera detects a person’s face within the area covered by the AF points, it will focus on them automatically. If there are multiple faces in the frame, it will focus on the face(s) that are closest to the camera.
If the camera doesn’t detect a human face, the selection of the AF point can become a little more unpredictable, but will generally focus on the closest and most dominant element in the area of the frame covered by the AF points.
Consequently, if the scene contains multiple elements with similar colour, tone and size, auto point mode should be avoided, as it may well focus on something other than the intended subject.
Auto-Area AF Mode was perfect for the photography of this sad event in Malaysia, the death of Sdr. Karpal Singh. My attention was on the event.
In the Nikon world there is also the 3D-tracking. In conjunction with AF-C it gives the best focus tracking method for subject moving in all the directions.
Advanced Auto Focusing technique
You now know that in single servo AF mode (AF-S) the focus distance is locked as soon as the camera has acquired focus, allowing you to recompose the picture, if required, before releasing the shutter (provided the shutter release remains half-pressed).
In continuous servo mode (AF-C) the focus distance is adjusted constantly while the shutter release is held down halfway, so the lens is focused on whatever part of the scene is covered by the selected AF point. If you need to recompose the photo, AF-C alone can complicate things and you may go out of focus and make a blurred photo.
An alternative and popular technique is to use the AF-L function, which decouples the activation of the AF system from the shutter release button.
This is sometimes called ‘back button focusing’. Some camera models as the Nikon D600 have a dedicated AF-L button, while others require the AF-L function to be assigned to one of its other external buttons, via the appropriate item in the camera’s menu system.
The AF-L button, or the button with the assigned AF-L function, acts essentially as an on/off switch for autofocus
- press and hold it down to lock the focus distance (AF-C stops working).
- release it to start again working in AF-C
For sport and wildlife photography this provides an almost ‘best of both worlds‘ situation if the camera is set to its continuous servo AF mode (AF-C), as it combines the capabilities of the AF system to track a moving subject with the ability to lock focus instantly to permit re-composition of a picture with the subject anywhere in the frame.
In this way your subject will be sharp, the background blurred and you have the composition you want 😉
Using back button focusing is also very effective for more static subjects.
Once focus has been acquired with the camera through AF-S, you just press the AF-L button to lock focus leaving you free to recompose at will and shoot as many pictures as you like, without having to worry about the AF system changing the focus distance.
If you haven’t tried this method before it may take a little time to become accustomed to it, but it’s very worthwhile, as it can simplify shooting in a number of situations, allowing you to work more quickly and with more consistent focus accuracy.
Auto focusing examples
Or what Auto focus mode when…
The rickshaw in Georgetown/Penang, Malaysia, capital of the Asian food and colonial architecture
Focus on the two ladies with AF-C (Continuous-Servo AF). AF Area setting: 9 points. I choose 9-points on the right of my photo to have a better composition, more dynamic. I wanted to give a sense of direction, otherwise missing if the ladies were right in the centre.
I usually pre-set my focus points, or single point, either on the right or the left side of my photo, almost never in the centre.
AF-S and single point area. Zoomed in on the name in yellow and red almost in the centre. Focus on it, AF-L to lock the autofocus and zoomed out. This gives an even greater depth of field as I wanted to really blur the candles on the background and keep the names very sharp
Sunset in Langkawi, Malaysia
It was already dark and I did try to autofocus however the amount of light was just not enough and the autofocus mechanism was going back and forward without locking on the beach, my main subject. Decided to move to manual focus and increase my F-Stop to have a longer field of focus. I wanted to have just a silhouette of the person in the foreground and I measured the light on the sunset. I used a tripod as my exposure time was too high for hand held.
I was waiting for Peter Sagan (the cyclist in green). When I saw him I was ready with my camera setting in AF-C (Continuous-Servo AF), locked the focus on him with AF-L and just followed him till the man with the pink hair was in the shot as well. Happy with the result
Focus on the three coming riders with AF-C (Continuous-Servo AF), locked the focus with AF-L and recomposed the photo to include the family cheering all the cyclists in the Tour De France. Although I focused on the riders I wanted the family to be part of this photo, they just add a human touch to a world event.
I wanted to take a photo of Nibali, the yellow jersey at the Tour De France 2014. I wanted to include the crowd and the French village made of walls and old houses. I saw this small lane. I walked in few minutes before the rider were coming.
I set my camera to Single-servo AF (AF-S) and focused to the middle of the street (I used a pedestrian that was walking there). I waited. When the riders were coming I locked my focus (AF-L) and started shooting (8fps). One of them was including Nibali :D.
I could have reached the same result moving to Manual focus, instead of pushing AF-L
This was a difficult one. I was very close to the riders, they were coming fast, there was not enough light to have automatic focus. I decided instead to move to manual and concentrate on the riders in the middle of the group, moving my camera to follow the riders, a techique called panning.
Yes, of course I was lucky as well with the end result LOL but, as I usually say, learn to set your camera and choose your composition as Ms.Luck may not show up everyday 😀
This ends our tutorial on focusing. I really hope it helped you and your photography and remember that practice is always the best training.
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