The photographer would wear the 6-inch diameter chrome camera under his vest. The lens would poke out a buttonhole, and the shutter could be tripped by pulling a cord. The camera could shoot six images on a circular dry plate; the photographer would advance the plate by patting his chest to activate a lever. [...] The camera, which retailed at $15, was popular among amateurs and professionals alike.
I didn't realize exposure times of film were short enough to get snapshots like this in the 1880's.
Disc shaped and all metal in construction, at first glance the camera resembles a cross between a frisbee and a hip flask. Thin enough to be worn unobtrusively beneath an ordinary waistcoat, it hung from the photographer’s neck on a strap. The f10, fixed-aperture lens poked through a buttonhole of the waistcoat and, as a further aid to concealment, was designed to look like a button.
Exposures were made on a circular glass plate that was rotated after each exposure by turning a knob protruding from the front of the camera. Six photographs, 40mm in diameter, could be taken on each plate. Rotating the knob also set the rotary shutter, which was released by pulling on a length of string which dangled from the bottom the camera.
Two research breakthrus in the 1870s paid off by the 1880s
The first was cooking the gelatin emulsions makes the grain much larger but much more light sensitive.
The second (minor) one was adding small amounts of dyes to emulsions make them sensitive to colors other than blue, so B/W looks more realistic and also is obviously more sensitive.
"I didn't realize exposure times of film were short enough to get snapshots like this in the 1880's."
Neither did I. If fact my immediate reaction was "bullshit". I honestly thought this was fake until I saw your comment. Thanks for doing the legwork/verification.
Kinda odd that in 2018, these types of buttonhole cameras aren't super easy to find. I mean they have them on spy gear websites, and we all have phones, and there was Google Glass, but nothing super cool that's an obvious choice.
The Narrative Clip is similar - the Clip 2 sells for about $200, which isn't too far off from the adjusted price. It's not branded as a spy camera, but looks pretty discreet.
A 640x480 VGA camera for Arduino, where the lens is about 1cm, so it'd fit pretty well, is about $5. Throw in a Nano for the board for another $5, and an SD card module for another $5, and you can probably build your own for about $20 all up.
Prebuilt, I've seen a few wireless "drone" cameras of similar quality for $20, and a few Chinese shops carry cameras like this [0] for $25 or so.
But... If you want better than a crappy VGA, you'll be looking for a while.
https://www.mercurynews.com/2012/08/16/alexiadis-vest-pocket...
The photographer would wear the 6-inch diameter chrome camera under his vest. The lens would poke out a buttonhole, and the shutter could be tripped by pulling a cord. The camera could shoot six images on a circular dry plate; the photographer would advance the plate by patting his chest to activate a lever. [...] The camera, which retailed at $15, was popular among amateurs and professionals alike.
I didn't realize exposure times of film were short enough to get snapshots like this in the 1880's.
According to https://en.wikipedia.org/wiki/Timeline_of_photography_techno..., this change was in 1878: Heat ripening of gelatin emulsions is discovered. This greatly increases sensitivity and makes possible very short "snapshot" exposures.
edit:
Also, $15 is about $400 now: http://www.in2013dollars.com/1890-dollars-in-2018?amount=15