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What does Single Lens Reflex actually mean?

The 'Single Lens' bit is easy. I can count.

Does the 'Reflex' that it has good reflexes and it should be a slip fielder?

I did a quick google but was overwhelmed with results.

Chris
Pondering the really important issues.

SLR on our Wiki!

Wait 'till we show you a TLR (Twin Lens Reflex)... then you'll really be confused!

Original cameras were a lot like the larket format cameras that are still in use today, the photographer composed the image on a large ground glass screen positioned on the focal plane and then once everything was composed and focused they would close the shutter, insert the film holder, expose the film and start all over again. The process would take about two to five minutes in all to set up.

By the turn of last century cameras different cameras used external viewfinders for the sake of making composing images quicker. Some used a simple wire frame and other used an optical viewfinder located to the side or above of the camera. The Leica camera was the first 35mm camera and eventually it was fitted with a range finder type viewfinder that was coupled to the main lens so that the photographer could adjust the focus with accuracy. All of these options though had the problem of parallax error ... the viewfinder saw a different prespective to the main picture taking lens.

The Single Lens Reflex camera was invented about the 1950s and it solved the problem by using the same picture taking lens to service a viewfinder as well. To do this they used a reflex assembly ... effectively a retracting mirror in front of the film plane, focusing the image on to a ground glass screen that was then viewed through another prism. Once the picture was composed and focused the photographer pushed the shutter release button, the mirror flipped out of the way, the shutter opens to make the image and then closes. The mirror flicks back down and you can see to compose the next image again.

The reflex component refers to the mirror and its action ... hope this is a help!

The reflex component refers to the mirror and its action ... hope this is a help!

Yes, thanks.

then you'll really be confused!

Probably no more than usual.