The Single lens reflex (SLR) system was a game-changer in film photography because it allowed the photographer to see exactly what the camera is seeing through the lens. While digital photography has succeeded film, the operational concepts and mechanics of a traditional film SLR remains the same in the modern digital SLR cameras.
Here’s a neat little animation from Harman Technologt, the folks behind the Ilford brand of film, that breaks down exactly how a basic film photography SLR (single lens reflex) camera works.
This video will reveal nothing new or ground breaking for the seasoned photo nerds out there, but it’s one of the simplest and shortest explanations of how a camera works that we’ve seen.
Light reflected off the subject enters through the front of your lens, where it goes through one or more elements. It then passes through the lens aperture. This allows you to control how much light you let in. Then it goes through another glass element. From here, it bounces off a mirror, into a prism above it.
There’s usually a focusing screen of some type in between the mirror and the prism. The prism then reflects internally to produce the image we see when we look through the viewfinder.
When you press the button, the mirror flips up. This is why you can’t see through the viewfinder when you’re taking a shot. The image simply isn’t reflecting off the mirror and through the eyepiece anymore. Instead, the image is projected straight toward the film plane. Or, in the case of DSLRs, the sensor.
Then, the shutter opens, exposes the film or sensor, the shutter closes, the mirror flops back down, and you can see through the viewfinder again.
If you want to see some more of Ilford’s videos, and be notified about future ones, check out their YouTube Channel.