Green Screen - Chroma Key is an iPhone application designed for shooting videos and photos using a camcorder or photo camera with the device. The app allows users to replace the green background with a screen capture, providing a seamless and professional chroma key effect. It features markers for tracking device motion, green and blue chromakey options, and brightness control for optimal lighting adjustments.

Users can easily manage glare issues by adjusting the screen brightness or reducing ambient light. In cases where ambient light cannot be controlled, a polarized filter can be used for better results. Additionally, users can conveniently change settings by simply shaking the device, enhancing the user experience and workflow efficiency.