What is necessary for all types of cameras to function properly underwater?

For cameras to function effectively underwater, proper housing is essential. The housing ensures that the camera is protected from water ingress, which can lead to serious damage or total failure of the equipment. Proper housing is designed to withstand the pressure at various depths, while also providing access to necessary controls and features of the camera for photography underwater.

Without adequate housing, regardless of lens quality or water clarity, the camera would be vulnerable to water damage, making it impossible to capture any images. This protection is paramount for both digital and film cameras when submerged. High-quality lenses, clear water conditions, and special underwater film may enhance image quality and shooting experience, but they cannot substitute the need for proper housing, which is a fundamental requirement for underwater photography.