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Old Dec 11, 2003, 11:59 PM   #11
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Default Re: SLR? ZLR? Changing definitions

Originally Posted by bcoultry
I always thought a single lens reflex camera was so designated, not by the removability of its lens, but by where the image in the viewfinder comes from. Am I wrong?
Barbara, everyone seems to have forgotten where the 'reflex' terminology comes from.

Antique plate cameras have wire frame or separate optical viewfinders, but you get a direct, inverted view on a ground glass screen under the black cloth hood, and you put a plate or flat film in front of the screen to take the shot. You see what you'll get, whatever lens is fitted. When consumer photography became popular, all cameras acquired separate optical viewfinders, looking in roughly the same direction as the lens. This layout had parallax problems, and you couldn't focus accurately, unless you had a artillery-style rangefinder, and you needed a new viewfinder for any change of lens.

My own second 'real' camera (1962) was a Russian plastic 'Lubitel 2' TWIN LENS REFLEX, a pale but effective imitation of classic TLRs like the Rolleiflex. You had an upmarket optical viewfinder with a good viewfinder lens above the prime lens, *reflecting* the viewfinder image through 90 degrees on to a horizontal ground glass screen. The prime and viewfinder lenses were geared together, so that focusing one focused the other.

As the two lenses weren't in the same place, and had different apertures, you got parallax problems in close-ups, and the depth of field you saw wasn't necessarily what you'd get on the negative. If you changed the lenses, you needed an expensive matched pair.

The SINGLE LENS REFLEX got round this by interposing a flip-up mirror behind the prime lens, compressing the two lenses into one, and providing mirror-image WYSIWYG on a ground glass screen (horizontal, in the first instance). Sticking a pentaprism on the top gave a properly rotated image. Fancy rangefinders were incorporated as well, before autofocus was invented.

It now seems to me that any old consumer digicam with an LCD (or external) monitor provides all the WYSIWYG functionality of the SLR at a stroke, by displaying what the 'film' will see. Historically, all the D-SLRs with mirrors are an uncomfortable half-way house, dating from the days when you *couldn't* expose your actual sensing element (the film) because you'd fog it. All the best kit was on film SLRs, and slowly and painfully we've replaced the film with a CCD. This evolution still continues, but the mirror is clearly out on a dead-end evolutionary branch.

I suggest "Dodo-SLRs" as a suitable term.
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Old Dec 12, 2003, 8:07 AM   #12
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I ran over this defition of ZLR ans SLR

ZLR is a camera with a built in non interchangeable zoom lens

SLR is a camera which accepts interchangeable lens.

Found in Rick Sammon's Complete Guide to Digital Photography
page 165.

It sound kind of silly to me, either camera is still a single lens reflex since I have never seen a camera that can accept two lens at once.
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Old Dec 12, 2003, 10:27 AM   #13
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Reading all the above has led me to this conclusion: the current state of photographic technology confuses the terms--not to mention a lot of people. I've always thought the most important part of single lens reflex was the "single lens" part of it, so, when I look through the viewfinder of my old Konica or of my much newer E-20 and know that I'm essentially looking directly through the actual lens, I think of it as a single lens. The idea of both cameras is the same.

It seems that, in the end, all of us here are of one mind: until someone drives us nuts with yet another acronym, SLR works admirably.

The writer of the review in that magazine that got this entire thread started really ought to sort potatoes on a conveyor belt instead.
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