An optical apparatus includes an optical sensor configured to capture a digital image of an animal within a view area, a processor coupled to the optical sensor, and a memory coupled to the processor. The memory is configured to store instructions that, when executed, cause the processor to determine a distance to the animal, determine edges of the animal, and calculate measurements of selected portions of the animal in response to determining the edges and the distance. The memory further stores instructions that, when executed, cause processor to automatically calculate a prey score for the animal in response to calculating the measurements.