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Wednesday, 21 September 2016



Interesting, I agree with the mirror rather than movement, but that rather wide definition means that a Leica or other rangefinder is also a reflex camera by virtue of it's focus mechanism.


I think there is a danger of overthinking this, a reflex camera is one that is called a reflex camera. Your definition above of "If it uses a mirror for image preview, composing ..." would mean the Box Brownie is a reflex camera since it uses a mirror in the viewfinder to preview and compose.

And of course TLRs like the Rolleiflex, where the mirror is fixed.

TLRs are, by name and by common usage, "reflex" cameras, so that makes sense.

(So, also, "reflex" doesn't mean you view through the taking lens in all cases.)

Remember the "TLR"? The Twin-Lens Reflex? Of Rolleiflex fame? That bad boy was THE professional camera of it's time. It used mirrors that did not flip up, either. BTW, both Ricoh and Yashica also made TLRs, and the Yashicaflex was the camera that MANY students developed their skills on in college photography courses. I'm sure you remember this, Mike! ;-)

Yes, as in twin lens reflex. The mirror has it.

Well since we're stuck with the term "full frame" (aren't ALL current digital cameras using the full sensor and therefore by definition full frame?) then it's up to us as to whether the term reflex has evolved to mean a moving mirror rather than any mirror.

Language evolves, whether we like it or not.


Hi Mike,

I found this definition of a reflex camera on the web, but I am not sure of the source: -

reflex camera
a camera with a ground-glass focusing screen on which the image is formed by a combination of lens and mirror, enabling the scene to be correctly composed and focused.

And from Wikipedia: -

A single-lens reflex camera (SLR) is a camera that typically uses a mirror and prism system (hence "reflex", from the mirror's reflection) that permits the photographer to view through the lens and see exactly what will be captured. With Twin lens reflex and rangefinder cameras the viewed image could be significantly different from the final image. When the shutter button is pressed on a mechanical SLR the mirror flips out of the light path, allowing light to pass through to the light receptor, allowing the image to be captured.

I can't speak to the camera book linked here, but I was disappointed that his "500 cameras" book did not contain 1 APS camera.

My burning question is, how many angels, holding mirrors, can stand on the head of a pin?

BTW my Enormous Full Frame 4x5 is much bigger than your pathetic little 35mm full frame. 8-)

In fact reflex cameras are older than photography:


But in modern times we should confine mirrors to bathrooms only.

So is my 5x7 Stereo Graflex a SLR or a TLR?

Two lenses, one mirror, one ground glass, and one shutter, but both lenses are taking lenses as well as viewing lenses. It could be two SLRs but for the single shutter , mirror and ground glass.

I would add "... or beamsplitter" to the "mirror" reference. I would consider any camera with a prism beamsplitter, like many cinema cameras, to be "reflex" cameras.

Sony's SLT cameras do not use the reflected image for preview, just for autofocus. The SLTs use an electronic viewfinder driven from the main sensor.

> "If it uses a mirror for image preview, composing, and or focusing,
> it’s a reflex camera."

That very ecumenical definition also encompasses cameras with focusing aids relying on a moving mirror to determine the "distance" to the subject — i.e. to find the "range" of said subject...

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