Remote Follow Focus with Secondary Camera Distance Tracking
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Solution Overview
Problem
Current focus switching methods in film production face challenges such as inaccurate distance measurement, reliance on visible markers, limited performance in varying lighting conditions, and the need for manual measurement and operation, especially when dealing with moving objects and shallow depth of field.
Innovation Solution
A remote follow focus unit connected to a secondary camera system that continuously measures distances to objects, allowing for both automatic and manual focus switching without markers, providing tactile feedback and ergonomic design for prolonged use, and maintaining focus on moving subjects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual distance measurement and marking is used on the follow focus unit, then the operator can control focus switching manually with artistic freedom, but the process is time-consuming and requires pre-measurement of distances
Solution Approach 1:
The patent replaces the manual mechanical measurement and marking system with an automated optical/electronic distance measurement system. The secondary camera system captures images and a computer system automatically calculates distances to objects, eliminating the need for manual measurement and marking while maintaining focus control capability.
Solution Approach 2:
The system enables self-service operation where the follow focus unit automatically receives and processes distance information from the secondary camera system, and the computer system autonomously calculates distances and provides feedback to the follow focus unit without requiring manual intervention for measurement and calculation.
2Extent of automation
If beacon tags are placed on objects for distance measurement, then automatic focus tracking is enabled, but the beacons must be visible at all times which limits applicability especially with shallow depth of field
Solution Approach 1:
The patent makes the secondary camera system serve multiple functions: it acts as both a distance measurement device and a regular imaging device for monitoring object visibility. This allows the system to adapt to different filming conditions including shallow depth of field scenarios by switching between automatic distance-based focus control and manual operation when objects become invisible.
3Productivity
If a secondary camera system is used to measure distances automatically, then focus switching speed is improved, but the system complexity increases
Solution Approach 1:
The patent merges the secondary camera system, computer system for distance calculation, and follow focus unit into an integrated system. The communication interface and data processing are combined, allowing the secondary camera to directly provide distance information to the follow focus unit through the computer system, reducing overall system complexity while maintaining automated focus switching capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate and efficient focus switching between objects, reducing out-of-focus issues, allowing for artistic freedom with high precision, and eliminating the need for pre-measurement of distances, while maintaining focus on moving subjects.
Implementation Method 1
One camera or a stereo vision camera system can be used for the secondary camera system. It should be mentioned that there are different kinds of stereo vision camera systems for distance measurements
Data Source
Figure 1~2
AI summary
The present invention relates to a method for switching focus between objects (a, b, c, d, e) found simultaneously in an image area from a main camera (1) used in film production where the focus of the main camera (1) and a switch between different focus distances can be controlled by means of a remote follow focus unit (2) connected to the main camera. A secondary system (4) and a computer system (5) for tracking the distance to at least a first and a second object (a, b) is used to measure the distance (da, db) to both the first and the second object (a, b) simultaneously and continuously. The distance information from the secondary system (4) regarding the distance to the first object (a) is used by the follow focus unit (2) as a focus distance to set the focus of the main camera (1) on the first object (a). The distance information from the secondary system (4) regarding the distance to the second object (b) is used by the follow focus unit (2) as a focus distance to switch the focus of the main camera (1) from the first object (a) to the second object (b).The secondary system (4) and the computer system (5) obtains the distance information by means of a secondary camera system (41).