Furthering the versatility of the focusing system, different AF-area modes can be selected to support varying types of subject matter:

• Single-Point AF: The camera uses a single point to find focus.
• Dynamic-Area AF: Available with 25, 72, or 153-point selections, this mode uses a primary single focus point to lock onto focus, and then makes use of the surrounding points for maintaining focus while tracking erratically-moving subjects.
• Group-Area AF: This mode treats smaller groups of AF points as a single point for a wider field of recognition, and is well-suited to tracking faces or other detailed subjects.
• 3D-Tracking: Using a subject's color information, this mode utilizes all 153 points to maintain focus on a moving subject while half-pressing the shutter button.
• Auto-Area AF: This mode makes use of all 153 points to quickly identify the main subject, and then prioritizes recognized faces as portrait subjects in any AF servo mode.

Lastly, a unique auto AF fine-tune function can be employed to ensure the best possible focus for each mounted lens. Rather than relying on photographing distance charts, this function lets you achieve precise focus manually in live view, and then have the AF system calibrate itself to the fine-tuned focus position in order to alleviate front- and back-focusing issues.

4K UHD Video Recording and 8K Time-Lapse

Utilizing the sensor and processor attributes for more than just still imagery, the D850 is also a more-than-capable multimedia camera. Video recording is possible at 4K UHD (3840 x 2160) using either the full-frame area or a DX crop area in 30p, 25, or 24p frame rates. Full HD 1080p video recording is also supported at up to 120p for slow motion playback, and video files can be saved to the in-camera memory cards or as an uncompressed file to an optional external recorder via HDMI out.