What is a diaphragm?

Aperture is easy. In a nutshell, the diaphragm is a device in the lens that measures the amount of light.

Nikon Nikkor 105mm 1: 1.8 (AI-S) aperture blades on ZK
Aperture device in the Nikon Nikkor 105mm 1: 1.8 (AI-S) lens

For a better understanding of the operation of such a device, I will give an example from life. When people look at the sun, they squint their eyes, that is, they reduce the gap through which light passes. If people had not squinted, the sun would have burned the retina of their eyes with their strong light. At night, you need to do the opposite – open your eyes wider to capture more light, while the pupils also expand. Eyes with large pupils have many animals that need to see well at night.

Often the aperture is also called ‘aperture’ or ‘aperture’ or ‘relative aperture’ or ‘number F‘. These concepts are strongly interconnected and for many photographers are synonymous. But among them there are small differences described below. Continue reading →