Graflex Speed-i-o-scope

[Bill_1856]

There's one on ebay right now. What is it? Thanks.

[Nick_3536]

The way it was explained to me. In a land far before recorded history they used to use them to flash things up on a screen. It was some sort of ancient teaching device. This was not long after the invention of fire.

OTOH it fits on the front of smaller barrel lenses.

[Dan Fromm]

The way it was explained to me. In a land far before recorded history they used to use them to flash things up on a screen. It was some sort of ancient teaching device. This was not long after the invention of fire.

OTOH it fits on the front of smaller barrel lenses.The device you're thinking of is called a tachistoscope. One application was training antiaircraft gunners to recognize aircraft silhouettes rapidly. Another was in "speed reading" classes. I took such a class once, accompanied by my pet Woolly Mammoth. Single-speed press shutter in the thing, IIRC.

[Bill_1856]

Thanks. I guess it came AFTER my time in the trenches.

[Donald Qualls]

The Speed-i-o-scope appears to be an accessory front shutter for use with barrel lenses. It gave timed slow speeds (useful for Speed Graphics, slowest timed speed was about 1/10 on the focal plane shutter), and may have had flash synch or been usable with an external synchronizer. This had a market because, through the pre-Anniversary Speed Graphic model, these cameras were sold with shutterless lenses (a shutter on the lens was redundant until flash synch became a necessity, or unless you needed timed slow speeds). Adding a Speed-i-o-scope was a lot cheaper than buying a new lens in shutter.

It was also usable with view cameras with the (then) plentiful 19th century brass lenses, many of which used Waterhouse type stops; this device provided both aperture and shutter for lenses of that type. It might even have been used with process lenses for copying.

[Nick_3536]

It's a pretty small opening on this. IIRC only about 1.5". Plus that's the outside diameter of the lens it'll fit. I know it will fit on some barrel lenses but I'd be suprised if it was designed for that.

The one on Ebay is labelled Graflex but my SVE Speed-i-o-scope is labelled

manufactured by Wollensak for
Society for Visual Education, INC. Chicago, USA

[Donald Qualls]

Hmmm. Maybe it *is* designed for tachistoscope operation. But if so, why would it have an aperture scale on the front, and why so small (yeah, okay, use of any existing shutter with minimal modification)? There aren't many projection lenses that size, either, but there are a fair number of old brass lenses in that size range...

[Nick_3536]

The f/stop scale again sort of points to something not aimed at Pro photographers. It is labeled in F/stops but it's also labeled in Bright,Medium,Dim and Very Dim. Plus the F/stops would only match one focal length. What's the point of marking it if the F/stops would be wrong for the majority of lenses?

My guess is Wollensak didn't re-invent the wheel. Somebody wanted a shutter to do a job and they basically took something off the shelf. Maybe they couldn't figure out how to leave off the aperture? Or maybe it would have cost more so they left it on. Or maybe it was intended to teach night vision? Close the F/stop and make it tougher on the class.