What is a "twin-lens reflex camera (TLR)"

[ericmark]

I started to read the Ansel Adams books on line.
http://manualesdecine.files.wordpress.com/2012/05/the-camera-ansel-adams-series-no-1.pdf
http://manualesdecine.files.wordpress.com/2012/05/the-negative-ansel-adams-series-no-2.pdf
http://manualesdecine.files.wordpress.com/2012/05/the-print-ansel-adams-series-no-3.pdf
In the first one he makes reference to Twin-lens reflex camera (http://en.wikipedia.org/wiki/Twin-lens_reflex_camera) and I realised I also called them twin lens reflex cameras. However reflex refers to moving the mirror it's a reflex action as the mirror swings out of the way with a SLR before taking the photo. However with the so called "Twin-lens reflex camera" the mirror seems to be static there is it seems no reflex action. So how did it get the name? I am guessing at one time the mirror did move but when and with what camera?

[Marko]

I do not know the answer, but I'm guessing the mirror moves. Gonna try to find out for you though.

[Runmonty]

Good question -

Wikipedia says the reflex actually relates to the reflection not the reflex action of the mirror?? Reflex camera - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Reflex_camera). Dont know if this is true or not?

Or could just be a misnomer from SLR- either way I dont believe the mirror moves - Good illustration here Odd Adventure: Twin Lens Reflex Camera (TLR) (http://kenas-dayne.blogspot.com.au/2011/09/twin-lens-reflex-camera-tlr.html)

I dont think this is it, but another stray thought is that maybe "reflex" refers to the reflex action of the shutter as opposed to the mirror??

You have me intrigued now too

[Ron Cardinale]

"Reflex" refers to a reflection.
Like so many words, it has more than one definition depending on its context. In the case of these cameras, it's about reflection.
As far as I know, there aren't any TLR cameras that have a moving mirror. That's considered one of their advantages because the viewfinder doesn't go dark at the moment of exposure.
Reflex - Definition and More from the Free Merriam-Webster Dictionary (http://www.merriam-webster.com/dictionary/reflex)

[ericmark]

I selected the Oxford Dictionary as being about the first of the English dictionaries and it states:-

reflex
Pronunciation: /ˈriːflɛks/

noun

1 - an action that is performed without conscious thought as a response to a stimulus:a newborn baby is equipped with basic reflexes
(in reflexology) a response in a part of the body to stimulation of a corresponding point on the feet, hands, or head: [as modifier]:reflex points

2 - a thing which is determined by and reproduces the essential features or qualities of something else:politics was no more than a reflex of economics
a word formed by development from an earlier stage of a language.

3 - archaic a reflected source of light: the reflex from the window lit his face

adjective

1 - (of an action) performed without conscious thought as an automatic response to a stimulus:sneezing is a reflex action

2- (of an angle) exceeding 180°.

3 - archaic (of light) reflected.
bent or turned backwards.

Derivatives

reflexly
adverb

Origin:

early 16th century (as a noun denoting reflection): from Latin reflexus 'a bending back', from reflectere 'bend back' (see reflect)
3 - archaic a reflected source of light: the reflex from the window lit his face would seem to be the answer here. So any camera with a mirror or prism would be a reflex camera. It has been discussed to if a 4/3 camera should be called an SLR as it has no mirror. It would seem no it's not an SLR. But I had never considered reflex as a static function seems I was wrong.

[Jim Scrimger]

If this is not a trick question OMG am I old. Probably the best known TLR is the Rollieflex. The viewing lens is on top and you look down into the fixed reflex mirror. The actual taking lens (usually f3.5 or f2.8)
is below the viewing lens. Film was 2 1/4" square and they produced an excellent negative. Way back in the early 1900 there was a Graflex 4x5 version. Ansco and Kodak also made good less expensive versions.

[JAS_Photo]

Ask and Wiki has the answer, basically what Jim says above. :)

Twin-lens reflex camera - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Twin-lens_reflex_camera)