Without proper focus, most of your photos will come out looking a blurry mess. That’s why there are a myriad of options for focus on your camera. Below we will go over all of the options related to focus operations on your Sony Alpha a5100.

Most cameras have two main modes for focus adjustment: manual focus, where you adjust the focus by hand to set the focal point where you want, and autofocus, where the camera selects focus for you. Autofocus technology has advanced in many ways over the years, and there are now a multitude of options for how Autofocus works. We will get to Autofocus options below, but first, let’s cover the focus modes available on the a5100.

Focus Modes

The various focus modes largely change how autofocus operates when shooting. To change the focus mode, press the Menu button, navigate to the third page of the Camera Settings tab (camera icon), then select Focus Mode. The focus modes are:

  • Single-Shot AF (AF-S)
    The camera will autofocus when you half-press the shutter button.
  • Automatic AF (AF-A)
    In Automatic, the camera will switch between
  • Continuous AF (AF-C)
    When the shutter button is half-pressed, this mode will continuously focus on moving objects in the frame.
  • Direct Manual Focus (DMF)
    DMF mode will autofocus with a shutter button half-press, after which you can fine-tune focus using the lens’ focus ring.
  • Manual Focus (MF)
    As the name implies, focus is manually adjusted using the lens’ focus ring.

Autofocus Area

While the focus modes above change when autofocus begins focusing, a critical component is where the camera autofocuses to. That’s where the Autofocus Area setting is important. The various Autofocus Area modes adjust where the camera focuses in the frame. The Focus Area can be changed by going to the third page of the Camera Settings tab in the settings menu, and selecting an option from the Focus Area menu. Here are the autofocus area options and their best use cases:

  • Wide
    Wide mode attempts to focus on as much of the frame as possible, with no bias. This mode is useful for scenes with a lot of action, such as wide-angle sports and crowds.
  • Zone
    In Zone mode, you select one of 9 focus zones in the frame (in a 3 by 3 grid). With this mode selected, you can use the multi-controller directional keys to switch between zones.
  • Center
    Center mode uses the center of the frame to find focus. This is the fastest mode and most useful when you know you can center your subject in the frame.
  • Flexible Spot
    Similar to Center mode, Flexible Spot uses a single spot in the frame to find focus. You can select between small (S), medium (M), and large (M) sized spot, and you adjust the location of the spot using the multi-controller directional buttons or using the touchscreen after selecting this focus mode. Once you have selected a spot, focus will remain there until you change modes or select Flexible Spot again.
  • Lock-on
    Lock-on is a feature that can use any of the above focus area options with the addition of a powerful autofocus feature that will lock focus onto a subject and remain there, even when the subject or the camera moves.

Autofocus Options

There are four additional settings for autofocus. AF Illuminator can be found in the third page of the Camera Settings tab of the settings menu, and can be switched between Auto and Off. AF Illuminator is a small light on the front of the camera that aids in finding focus when using any autofocus mode. Although it’s best to be left on Auto as it makes autofocus faster, the light can be turned off when shooting subjects that might be sensitive to the light, such as small children. The Pre-Autofocus is found on the third page of the Custom Settings tab (gear icon) in the settings menu. Pre-AF will autofocus continually with any autofocus mode, even when the shutter button is not half-pressed. It’s best to leave this off, as it can drain battery from the camera continuously driving focus.

The final two options relate to autofocus in Movie mode. AF Drive Speed in the fourth page of the Camera Settings tab in the settings menu, and can be switched between Fast, Normal, and Slow. When shooting photos, faster autofocus is almost always desirable, but fast switches in focus can be jarring in video. The AF Drive speed adjusts the speed at which the camera readjusts focus during Movie mode. AF Track Duration is just below AF Drive speed in the fourth page of the Camera Settings tab, and can be set to Normal or High. Setting this option to High can be helpful when shooting video with action or high-speed subjects, as autofocus will attempt to track the subject for longer than when set to Normal.