You can shift the focus back and forth between two preset focus positions that have been recorded beforehand.
For example, when shooting video, you can change the focus position within the frame at a designated speed to create a powerful visual transition. This feature is useful for various creative shooting situations.
Click [Custom Switch Setting] or [Focus Set Button Setting] shown at the top-left of the home screen.
* [Custom Switch Setting] or [Focus Set Button Setting] will be displayed depending on the lens.
* Download the TAMRON Lens Utility >>
On the [Custom Switch Setting] or [Focus Set Button Setting] screen, click [Select].
From the selection screen, click [Select] for [A-B Focus].
* Depending on the lens, functions apearing on the screen will differ. Check the list to find capability of your lens.
TAMRON Lens Utility Compatible Lens List >>
The focus speed selection screen is displayed. Select the desired [Focus Speed] for video shooting, and then click [Save] to complete the setting process.
* You can return to the previous screen by clicking the [Return] button.
* You can set the focus speed when shooting video. When you are shooting still images, the focus speed automatically defaults to the fastest speed.
* The focus speed is set to  by default. The larger the negative value set, the slower the focus speed.
How to shoot automatic "pull focus", a technique in video shooting that changes the focus position within the frame.
* A-B Focus is easier and more accurate if you use a tripod to secure the camera position in place.
Note: When you cannot change the focus mode to AF
If the focus mode cannot be selected from the camera body, press the [Focus Set Button] to return to AF mode.