Filming Lens With Fixed Elements for Focus Breathing Control

The lens is divided into multiple lens groups (first through fifth lens groups) with different functions. The first lens group has positive power, the second has negative power, the third has positive power, the fourth has positive power, and the fifth has negative power. This segmentation allows each group to be optimized for specific functions, with the second and fourth groups serving as focus groups that move independently to suppress focus breathing while maintaining overall system manageability.

The patent implements dynamic focusing by making the second and fourth lens groups movable along the optical axis. These focus groups can be independently adjusted during focusing operations, allowing the lens to dynamically adapt its internal structure to maintain consistent angles of view across different focal distances, thereby suppressing focus breathing while enabling flexible focusing control.

The patent carefully selects lens materials with appropriate temperature coefficients of refractive index for each lens group. By controlling and balancing these optical parameters across different lens groups, the system compensates for temperature-induced refractive index changes, maintaining focal position stability despite environmental temperature variations.

The lens employs composite material selection with different glass types for various lens groups. Each lens group uses materials specifically chosen for their thermal-optical properties, creating a composite optical system where the combined characteristics of different materials provide thermal compensation, reducing focal position drift caused by temperature changes.