The Sony A6000 is an upper-level enthusiast's camera wrapped in a mid-level consumer body. There is a lot of extended capability to tap in to, but the potential is somewhat hampered by a user interface that doesn't always separate the casual aspects of the camera from the more advanced enthusiast-oriented functions. This is quite apparent in the way that the camera's autofocus system operates; it's extremely capable but the menu system does not give you an indication as to which methods are best with which situations. In cooking terms, the user design shared by the A6000 and A5100 has many ingredients but is lacking recipes on how to put them together. It also does not help that the owner's manuals are a bit on the short side for cameras with such a deep menu systems. Even with minimal user experience these cameras can be quite capable, but a little bit of understanding will go a long way towards getting the most out of their sophisticated autofocus systems.
The following is not so much a comprehensive instruction manual on how to use the A6000 focus system so much as it is a guide to the different behavioural roles of the camera. Rather than focus on menu items, the following is more about how those different functions fit together in the big picture. The A6000 setup has a high degree of granularity; most of the functions are self-explanatory but some functions require more than a simple description in order to understand their nuance. The menu structure works best if you think of the settings in terms of broad function groups
- Ambient Settings: e.g. pre-focus, focus detection, lock-on
- Drive mode (how to deal with subject movement)
- Area Mode (levels of precision)
Proficient use of the A6000 comes with how this settings are combined. There is a lot of room for creative construction in how you use the AF system; in many ways, it is like setting up a race car for different road courses.
Note for users of the A5100: The same principles apply as for the A6000, except that you must enter the menu (Camera Settings>3rd Screen) to change the focus area and drive mode. As well, navigation incorporates the touch screen instead of using the jog dial. Even though the A5100 is designed primarily as a point-and-shoot camera, in some ways, its touch-screen capability make it easier to focus than the A6000. However, getting to this functionality isn't as quick because of the reduced number of physical buttons. With enough setup time, both cameras can perform at roughly the same level of autofocus performance, the difference is that it is easier for the experienced user to set the A6000 into the desired AF mode.
Pre-AF is a feature where the camera will focus on whatever it finds to be in front of it even before the shutter button is half-pressed. This increases the subjective speed of the autofocus system, but it also increases battery drain. The camera is not actually focusing faster, it's just that a portion of the AF time occurs in the interval when the camera is held up for shooting but before the photographer is ready to shoot. In situations where the subject distance is changing rapidly, pre-AF is less helpful.
Like many point-and-shoot type cameras, the A6000 has the ability to automatically detect human faces and lock focus on them. Sony takes it a step further by adding smile detection and the capability to register faces. Unless you are planning on using the camera in completely automatic mode, or plan to hand the camera to a person not familiar with photography, it is highly recommended that you turn off face detection. The problem is that it actually works too well...yes, you read that right. The A6000's AF system tends to prioritize face detection ahead of whatever AF area mode that you are in. This makes the behaviour of the system somewhat unpredictable if you are trying to shoot deliberately... you might want to pick a particular focus point that isn't a face, but the camera won't let you.
However, if you only intend to sue the camera in automatic mode, face detection is not a bad proposition for photographing people. Smile detection will automatically trigger the shutter when the camera sees a face smiling; it works better than it has any right to. Face registration is a memory bank with 8 slots for commonly photographed people. Once a face has been registered the camera will be able to lock focus quicker when that person is in the scene. Admittedly, face detection is for those who aren't serious about photography, but it is nonetheless a beneficial feature. Overall, letting the camera automatically focus on faces will produce more accurate results than using the focus-and-recompose method.
Lock-on is not a clearly implemented feature, nor is it consistently applied across the E-Mount and FE-mount cameras. It's function is easy to understand: when activated, the camera will attempt to maintain focus on a subject that moves laterally across the frame. The problem with lock-on is that it is poorly explained in the manual, and that its implementation varies depending on which focus mode that you are in. These are the three settings:
- On with shutter
This is the how the menu looks like on-screen:
"Off" is easy enough to understand. "On-with shutter" means that the lock-on function is always activated when the shutter button is half-pressed. The problem is with the intermediary option "On".
- In Wide or Center Spot focusing modes, pressing the center button once brings up the lock screen. Pressing the center button again activates lock on.
- In Zone or Flexible Spot focusing modes, pressing the center button lets you choose whether to turn the lock-on feature on or off. If you choose "On" you must activate the feature by pressing the center button. Otherwise, the control is the same as in wide or center spot modes.
Lock-on is designed to look for either the closest or the most contrasty subjects. It is important to keep this in mind when you are focusing on subjects that run obliquely towards the cameras, as the camera may lock-on to a portion of the subject that you don't intend to focus on. Lock-on is active when the focus indicator switches from the the standard focus box (or sparkly-dots in AF-C mode) to a rectangular double outline of the subject.
The difference between how subject tracking in lock-on works is from AF-C is subtle. AF-C in Zone and Wide Area modes works fairly similar to how side-to-side tracking works in enthusiast level DSLRs (such as 3D-Tracking mode in Nikons). With the Sony in pure AF-C mode, if you lose the subject because it passes behind an object or if you are panning too fast, focus won't be accurately re-acquired. Lock-on uses some element of color/shape recognition, so if focus lock is momentarily lost the camera has a chance to re-recognize the subject.
If you are using the A5100, provided that you aren't in a fully automatic mode, lock-on is activated by the touch screen when in you in one of the PASM modes, as the center physical button is reserved for changing the exposure mode. Basically, lock-on is touch-to-focus; when it is active you will see the subject outlined and tracked. While this is happening, a separate touch icon will appear that turns off lock-on when you touch it.
Lock-on is useful in situations where you have a slow moving subject that is large relative to the picture area. If you pair it with the spot-focusing modes you can focus-and-recompose without creating the focus shift error that would otherwise normally happen. However, it does have two downsides. The first is that the camera needs to use extra computational power to perform the shape recognition function that drives the lock-on features. This makes it a slow method for quick moving subjects. Lock-on isn't fast enough for sports or things like pet dogs. The second problem with lock-on is that it isn't precise when you are focusing on large subjects that run in oblique directions relative to the camera. With objects that oriented diagonally relative to the camera, lock-on will outline the whole object regardless of the difference between the near and far. In these situations this will make placing the point of focus exactly where you want it impossible; the end results will be the camera's best guess, not your exact intentions.
AF Drive Modes
The autofocus drive modes can be easily brought up in the main Fn button on the back of the camera. It is also the default function of the C1 button on the right side of the shutter button. The drive modes are:
- AF-S (Single shot)
- AF-A (Automatic)
- AF-C (Continuous)
- DMF (Direct Manual Focus)
- MF (Full Manual Focus)
AF-S (Single shot)
AF-S limits the autofocus action to a one-time focus acquisition. This mode is for non-moving subjects where you don't want the camera to accidentally re-focus on an unintended target, e.g., landscapes, architecture, adults, etc. AF-S will also consume less battery power, though not by a significant amount.
AF-A is a hybrid mode that is primarily single-shot like AF-S mode, but will switch to continuous (AF-C) if it detects that the subject is moving. Almost all modern cameras have a setting like this, and in almost every case it is a mode that is best left unused. The problem with AF-A is that it makes the camera's behaviour unpredictable; you, as the photographer, are handing over an element of control over to the camera. The issue with modes like this is that you don't have an immediate grasp of the threshold that will trigger the switch between single-shot and continuous action.
AF-C is the continuous tracking mode. It will also track motion side-to-side if you are in Wide or Zone focus modes. In Center or Spot modes, the camera will only continuously track the subject so long as the AF target box is held over the subject. The exception is if "Lock-on with shutter press" is active, in which case the camera will use the somewhat slower lock-on method to continuously track the subject. AF-C has obvious uses with sports and fast moving objects, but it is also immeasurably useful for children who only give the appearance of being able to sit still.
AF-C is the mode that you will want to use when you are using the shutter burst modes. The A6000 is capable of 11 fps but fast burst rates are useless unless the focus is placed accurately. It makes little sense to use a shutter burst with AF-S, as most situations don't require multiple shots of a non-moving object. However, when the subject is in motion it is a challenge for the camera to maintain focus lock. AF-S is a poor choice in these situations as the point of focus will fall behind the moving subject. When AF-C is activated, the camera will maintain focus with the moving subject and to some extent try to predict the velocity and trajectory after the shutter is released. In practice the A6000 in AF-C with shutter burst modes tracks objects as accurately as a mid-level DSLR, meaning that it is very good for everyday situations, but it isn't infallible. With all cameras, tracking subjects isn't a matter of yes/no, but a case of how high the keeper rate can be. Entry level cameras have poor keeper rates for moving subjects, meaning that only a few frames out of many attempts will be adequately in focus. Conversely, professional cameras allow for a higher, but still not perfect percentage of on-target shots. It's just that the pros only publish the ones that work and not the shots that they missed.
DMF (Direct Manual Focus)
DMF works like how the AF-S or USM autofocus motors work in Nikon and Canon cameras. DMF is a bit of a misnomer, as it isn't a manual focus mode so much as it is an autofocus mode with manual override. In DMF mode a half-press of the shutter works in the same way as AF-S mode; it's a single-shot focus mode. The difference is that the focus lock can be manually overridden so long as half-press is maintained. This mode works well if you have to do multiple instances of critical/close focusing in one session, but truth be told, it is not a mode that will be used often.
MF (Full Manual Focus)
'MF mode is the pure manual mode. If you also turn on focus peaking, manual focusing is not particularly hard to do, but there is one caveat. Sony's interpretation of focus peaking can be a bit on the "loose" side for some people, meaning that it tends to indicate a wider zone of acceptable focus than what some people would like. This makes for user-friendly operation, but if you aren't careful, it can mean that manual focusing with focus peaking might not be as precise as you think it would be.
Sensitivity and specificity are terms that describe how a an autofocus system can be tuned; the more sensitive a system is, the less specific it becomes. Put simply, sensitivity is the ability to detect if something is present; specificity is the ability to reject a false positive. In photographic terms, an autofocus system is sensitive if it can achieve focus lock, but it is specific if locks onto an object that the photographer intends to photograph. The trade-off between the two comes down to a simple matter of how wide of an area the autofocus system is examining. The wider the focus area, the more sensitive the AF becomes; at least something will be in focus. As you narrow down the area, the system becomes more specific to what you intend it to do, but it might take longer to achieve focus lock if the subject is small, moving or of low contrast.
The A6000's focus area menu is next to the drive mode option when you press the Fn button on the back of the camera. It is divided into the following modes:
- Flexible Spot
As you move down the list, the area options grow smaller in size and move operate in a less sensitive but more specific manner.
|Wide Zone: After shutter half-press|
Of the AF area settings, Wide is the least precise. Wide area mode basically allows the camera to focus anywhere in the frame that it thinks the subject is. If you will, this is the "mind reader" mode, because this is basically what you are asking the camera to do. Wide area is generally not useful for precision photography, as you have no idea where the camera will lock and the menu interface gives no indication as to its intentions. However, the A6000 will tend to look for the subject in the center of the frame and will lock onto things that are contrasty and generally closer to the camera. It's not completely unpredictable, but there are better choices.
One the A5100, Wide-Zone mode also has a touch-to-shoot function, which manually overrides the behavior of the focus area mode. If you just go by the physical shutter button, you will get the same semi-accurate guessing that the A6000 does, but the A5100 will also display a touch-to-shoot icon in the upper right of the LCD display. The touch-to-shoot function won't be active until you press this icon, An orange bar will appear in the icon when you tap it, indicating that touch-focus is armed. To turn off touch-focus, tap the icon again and the orange bar will disappear. When touch-focus is armed, the camera will focus and fire the shutter when you tap on any other part of the LCD screen. This function is available in Zone and Center area modes on the A5100.
Zone area mode is more restricted than wide.In zone mode, you choose the general area for the camera to look for a focus lock, and the camera will automatically chose a point within that zoom upon half-press. Like Wide area, using Zone in conjunction with AF-C will have the camera display a set of shimmering green dots instead of a target box as it tracks a moving subject.
|Zone Area with AF-C|
Provided that the focus lock is on your intended subject, the shimmering focus pattern lock will stay with the subject as it moves. The smaller dots that you see during AF-C mode are the individual phase detection zones spread across the image frame. As the subject moves, the AF detection is handed off from one detector to the next. The problem is that there is no clear indication as to what the camera is going to lock onto when you half-press the shutter button; the best description of the system is that it tends to pick up objects that are near the centre and close to you.
A good real-life example is if you focus on signage; if you are facing square to the lettering on the sign, the AF-C sparkle-dots will focus on the text. However, if you are facing obliquely to the sign, the camera will actually try to lock on the edge of the sign instead of the letters, as that is the closest detailed structure that the AF system sees.
Center mode is the least exciting, as it places a single target box in the center of the frame for you to aim at the subject. This is not a good mode to use for quality photography. If you only use it as is, then that means that your subject is always dead center in the frame, which makes for boring and sometimes awkward composition. Ther is also the temptation to focus-and-recompose in center area mode. In AF-S mode this will lead to focus errors as the camera will lock focus at one distance, but the distance of the subject to the camera will shift slightly depending on how far the frame is re-composed.
In AF-C mode with Lock-on, center mode becomes much more interesting as the camera will track the subject during re-composition, meaning that accurate focus is preserved. (As an aside, this is how the medium format Hasselblad H-series cameras work with their TrueFocus system. Hasselblad cameras only have one AF point, but you allow for accurately focused re-composition, they have an internal motion detector, similar to the ones used in cell phones. The end result is operationally the same as the A6000 with AF-C and Lock-On.)
Flexible Spot focus is the mode that most seasoned photographers will want to use. It works in the same way that basic AF-point selection works in a DSLR; there is a single point of focus and you manually position it across the image frame. When the camera is in flexible spot mode, the center button activates the AF position meter. The size of the spot can be changed from large to medium and small; for the most accurate results, it is best to use the smallest spot setting that can be consistently placed over your target. Spot focusing will not track an object side-to-side across the frame unless Lock-On is activated.
On the A5100, touch-to-shoot is not available on either of the two available flexible spot modes. If you are in flexible-spot mode, touching the screen moves the focus indicator but will not fire the shutter. The lock-on activation indicator will be present in the upper right of the LCD display instead.
Putting it all Together
In setting up the camera, the thought process flow is as such:
- Choose which ambient conditions you are want or are willing to live with.
- Identify if the subject is moving or not moving and choose the drive mode accordingly
- Match the area mode that is most appropriate to the drive mode.
The third is the key to getting a usable setup. As an example, it makes little sense to use Flexible Spot mode for precision if you are going to pair it with AF-A. The most important thing to remember is that even though there are many ways to setup the autofocus system, you will likely gravitate towards only one or two to suit your shooting needs. That's the key to understanding a system with a large degree of flexibility; first understand how various functions work, then decide which ones work best for you.
With thanks to Broadway Camera