Maker: Weston Electrical Instrument
Model: Model 617 (Type 1)
Designer: William N. Goodwin
US Patent: 2,073,790
Original Price: $33.00
Cell type: Selenium
Measure type: Reflecting/averaging
Sometimes it's obvious who invented something; sometimes it depends on how you define it. A good example is the automobile, which developed over time. Karl Benz is typically credited as "inventor" but you could name several other people as well, depending on what you define as being an "automobile."
Photoelectric meters are the same way. People knew for years that selenium cells generated electricity when exposed to light, but the problem was making this into a practical tool. Ultimately it came down to around three people who introduced photoelectric meters around the same time: Philip Gossen in Germany, J. Thomas Rhamstine in Detroit, and Weston Electrical of New Jersey. Rhamstine's showed up around 1928 and required a battery and described as being like an anvil. Gossen and Weston meters came out a few years later, but they didn't need batteries, so they were smaller and lighter and easier to carry. Plus—most other meters of this era were simply foot-candle meters and you were expected to consult a pamphlet or a table to figure out what your exposure was. My Gossen Blendux and GE DW-40 are perfect examples. This meter incorporated a calculator dial right on the face so you could do everything at once. It wasn't adapted for photography, it was meant for photography.
Regardless, it's a surprisingly slick meter. I was very surprised. It is very large (6½ inches long) and heavy—nearly 1lb. But it's got a heavy bakelite case, it has rounded ends and groves along the top and bottom so you can hold it like binoculars.
There's a button on the right side, along the top, which sits right under the user's index finger, which is used for changing the scale sensitivity of the meter. The meter normally reads for bright light (0-1,300 foot-candles), but if you press the button, the scale is 0-130 foot-candles (low-light). My General Electric from this period requires you to put a metal mask over the cell to cut the light.
Another interesting note: this is a true reflected light meter (its contemporaries were all incident meters of one form or another). The man who designed this, William Goodwin, claimed that they had made the meter itself, but were held up as they tried to figure out how to limit the light striking the selenium cells in a such a way as to mimic the angle that a standard camera lens would see (around 46°).
They tried a tube but didn't like it. Ultimately they consulted with a cinema engineer who suggested a honeycomb-type baffle. Goodwin claimed this was the final piece of the puzzle, and they put the meter up for sale.
I know all this little bit because DeJur used the "honeycomb" on their meters. Weston sued them for infrigement, and a synopsis of its development ended up in the Federal Reporter (see Weston v. DeJur). Weston lost on the grounds that the honeycomb idea wasn't patentable.
Here's another interesting web page for this meter: Scott's Photographica Collection.