While the human eye and image sensors in cameras share some similarities in capturing visual information, they also have distinct characteristics and limitations. The capture of light in low light conditions between the camera and the human eye are fundamentally similar in the sense that the captured light interact with a medium that converts the light signals into an electrical signal and the electrical signal is processed to form a final image. In the human eye the photoreceptors rods are are highly sensitive to light and are responsible for vision in low-light conditions. Similarly, camera image sensors can have different levels of light sensitivity, often referred to as ISO sensitivity.
The human visual system's complexity and adaptability, combined with the brain's processing capabilities, allow for a rich and dynamic visual experience. Rods are highly sensitive to light and are responsible for our vision in low-light conditions, such as at night or in dimly lit environments. They are concentrated around the outer edges of the retina. Rod cells contain a pigment called rhodopsin, which is sensitive to different wavelengths of light. When photons of light enter the eye and strike the rod cells, the rhodopsin molecules undergo a chemical reaction, triggering an electrical signal. This signal is then sent to the brain, where it is interpreted as visual information. Although rods do not provide detailed color vision, they are essential for peripheral vision and detecting motion.Â
Camera image sensors are the heart of digital cameras, responsible for capturing light and converting it into electrical signals that form digital images. In low light conditions, the light signals can be captured more efficiently by changing the ISO settings on the camera. By changing the ISO settings, a camera sensor’s sensitivity to light can be changed. A higher ISO setting increases the camera's sensitivity to light, allowing for brighter exposures in low-light conditions but potentially introducing more digital noise. Conversely, a lower ISO setting reduces sensitivity, resulting in cleaner images but requiring more light for proper exposure. Advances in modern digital camera sensor technologies have ensured that even at higher ISO settings, cameras can capture images in low-light situations with reduced noise, resembling the light sensitivity of rods.Photographers can often adjust the ISO to achieve the desired balance between image brightness and noise levels based on the available lighting conditions. The intensity of light hitting each pixel determines the amount of charge it accumulates and this is then processed by the camera's image processor to create a final digital image.