Watameter

Watameter I
image by John-Henry Collinson (Image rights)

Watameter was a widely-sold German series of accessory rangefinders of the photo accessory brand Wata. A Watameter I or a Watameter II could be used to measure distances between 55cm and infinity. It could be attached to a camera's accessory shoe. All Watameters have a knurled rangefinder thumbwheel, with a smaller knurled screw upon it as means to adjust the rangefinder to indicate infinity exactly at the upper end of its scale, i.e. at ∞. Another small adjustment knurl at Watameters' I, II and Super's side is for correction of the rangefinder images overlapping to make the devices optically functional.

Watameters were produced by the company Edmund Wateler in Braunschweig.

Watameter I, front plate variant
image by Dirk HR Spennemann (Image rights)

Watameter Condor's measuring range began with 3 ft.
image by John-Henry Collinson (Image rights)

Watameter Super
image by John-Henry Collinson (Image rights)

The Watameter II and the Watameter Super were versions, in which the distance could be read directly through the rangefinder ocular, left hand to the measuring spot. The Watameter II even had only that distance display inside whilst the Watameter Super's enhanced distance scale partially has to be read from the meter's thumb wheel's cm scale, i.e. all distances between 30cm and 50cm.

Watameter almost like the Watameter Condor, and a sample
of an almost equal watameter badged "Mastra - Germany",
obviously the same type as the feet-scaled rangefinder made for Photopia
image by Adrian Gee (Image rights)