How Leica Measured Shutter Speeds to the Millisecond with the Bare Eye

Alabama-based photographer and engineer Destin Sandin of the YouTube channel SmarterEveryDay just lately visited KameraStore in Finland. Sandin, whose movies ship in-depth technical data in an entertaining and comprehensible manner, realized about Kamerastore’s specialised restoration and testing course of, which incorporates utilizing period-appropriate equipment.

Past repairing and testing cameras, Kamerastore gives the world’s solely digicam mechanics coaching program and technician coaching college. It’s dwelling to tools and machines that may excite any images fanatic, particularly one as within the technical features as Sandin.

Sandin’s newest video goes behind the scenes at Kamerastore, together with a have a look at a really particular Leica testing machine from the Thirties. The machine permits a educated technician, like Ari at Kamerastore, to calibrate an outdated Leica curtain-type focal airplane digicam shutter. The machine depends upon a rolling shutter-like impact that enables a educated technician to calibrate a shutter by eye.

Leica’s first commercially obtainable 35mm digicam, the Leica 1(A), hit retailer cabinets in 1925. It, and later Leica cameras, have been among the many greatest in the marketplace. Like many later cameras, early Leica fashions included a shutter velocity dial on prime. This mechanical dial allowed the photographer to pick out a shutter velocity, like 1/1,000 second, for instance. The shutter velocity dial have to be exactly calibrated to the precise velocity of the shutter.

If the photographer selects the 1/1,000 second shutter velocity, meaning the shutter is open and the movie is uncovered to gentle for only one millisecond. Leica engineers wanted to tune its cameras to make sure that the shutter was open for the anticipated length, with excessive precision. That’s the place the particular calibration machine Sandin noticed in Finland is available in.

The machine measures a millisecond mechanically. Accompanying the machine is an unique Leica restore guide — in German, in fact — that features diagrams exhibiting exactly what the shutter ought to seem like by the machine at totally different shutter speeds. At numerous rotational charges, a correctly-calibrated shutter will produce differently-curved traces.

Not happy to go away such cool expertise behind in Finland, upon his return to the U.S., Sandin recreated the unimaginable machine utilizing a drill, ketchup bottle, and magic marker. Mixed with a phantom high-speed digicam and very brilliant Nanolux gentle that doesn’t flicker, Sandin can use the high-speed digicam to view traces on the ketchup bottle because it spins behind the digicam on a drill.

Utilizing an additive animation method, it’s attainable to see the curved traces like what was seen utilizing the devoted Leica machine. Whereas a ketchup bottle with marker traces could appear crude, Sandin’s setup is subtle. Leica technicians carried out these measurements with a single machine and the bare eye. Kamerastore’s expert technicians nonetheless do.

One other piece of the puzzle is making certain that the machine’s rotation, or ketchup bottle in Sandin’s case, matches up with a typical velocity. In any other case, the achieved shutter velocity measurements could also be incorrect. The Leica machine makes use of aliasing, very like a document participant, to permit the consumer to dial in a exact benchmark velocity. It’s an unimaginable machine.

Picture credit: SmarterEveryDay, Kamerastore