# Custom Variable 1 ### **Using Half-Press Duration for Autofocus (C Var 1)** **C Var 1** controls the **length of the half-press (HP)** signal that is sent to the camera before the full-press (FP) trigger. By extending this half-press duration, the sensor gives the camera time to perform **autofocus** functions before the image is taken. With newer **mirrorless cameras** offering highly advanced autofocus systems — including **animal-eye detection** — this feature allows autofocus to be used in camera-trap setups for the first time. When the half-press signal is active, the camera can detect and focus on the subject before the shutter is triggered, enabling the possibility of shooting with a **shallow depth of field** and precise eye focus, creating images that differ greatly from traditional manual-focus camera-trap photos. #### **Practical Considerations** - **Focus reliability:** Autofocus-based setups are inherently less reliable than manual focus. Some images may be misfocused if the camera fails to detect the correct point of interest or locks onto background elements. - **Lighting:** Autofocus requires **continuous light** to function. For nighttime use, **video lights** may be necessary, as flashes alone will not provide light until after focus is attempted. - **Timing:** The optimal half-press duration depends on the camera model and lens. Mirrorless cameras typically require between **0.2 s and 1 s** for accurate subject detection and focus acquisition. This setting introduces a new creative approach to camera trapping — enabling **autofocus precision** and **shallow-depth-of-field imagery** previously impractical with PIR triggers. While manual focus remains the most dependable method for critical work, **C Var 1** offers an exciting opportunity to experiment with modern autofocus systems for more dynamic and cinematic results.