Watkins - Antique and Vintage Cameras

Watkins Standard

1890

Early Model

R. Field & Co.

Birmingham

England

Image of Watkins Standard

Meter Type:
Actinometer.

Calibration:

A Actinic value: 2 - 100.
P Plate speed: 1 - 70 Watkins.
S Subject: 1 - 500.
D Diaphragm: f4 - f64, 1 - 256 US.
E Exposure: 1 - 900 (1/1000 - 900/1000).

Construction:
Brass with chain and cap, blue glass. 2 " in length.

Identification:
Simple block lettering.

Early Enlarging Model

Meter Type:
Actinometer.

Calibration:

P Plate speed: 1 - 100 Watkins.
S Subject 1 - 500.
D Diaphragm f4 - f64, 1 - 256 US.
F Enlarging factor: 30 - 2 - 30.
A Actinic value: 1 - 100.
E Exposure: 1 - 900 (1/1000 - 900/1000).

Construction:
Brass with chain and cap, blue glass.

Identification:
Simple block lettering.

Enlarging Model

Meter Type:
Actinometer.

Calibration:

P Plate speed: 1 - 200 Watkins.
S Subject: 1 - 500.
D Diaphragm: f4 - f64, 1 - 256 US.
F Enlarging factor: 21 - 2 - 18.
A Actinic value: 1 - 500.
E Exposure: 1 - 900 (1/1000 - 900/1000).

Construction:
Brass with chain and cap, blue glass.

Identification:
Flowing script.

Late Model

Image of

Meter Type:
Actinometer.

Calibration:

P Plate speed: 1 - 400 Watkins.
D Diaphragm: f4 - f90.
A Actinic value: 1 - 400.
F Enlarging factor: 25 - 2 - 3.
S Subject: 1 - 400.
E Exposure: 1/300 - 400s.

Construction:
Brass with chain and cap, blue glass. 2 ⅜" in length.

Identification:
Flowing script.

Late Model

c. 1900

Meter Type:
Actinometer.

Calibration:

P Plate speed: 1 - 400 Watkins.
D Diaphragm: f4 - f90.
A Actinic value: 1 - 200.
F Enlarging factor: 5 - 2 - 15.
S Subject: 1 - 200.
E Exposure: 1/300 - 400s.

Construction:
Brass with chain and cap, blue glass. 1 " in length.

Identification:
Flowing script.

Watkins' first exposure meter, the Standard, proved popular despite its cost. It remained on sale until the mid 1920s though it was largely replaced by the Bee (1902).

The meter uses a strip of sensitive paper, a small section is exposed to light until it reaches the density of a comparison tint. This gives the actinic value which is set on a calculator scale and combined with values for plate speed, diaphragm and subject. The result is the required exposure time.

Early models have 5 scales and a blank ring, they are (in order back to front): A P S D E with a blank ring between the D and E scales. Later models have the dials in different orders. Early models have the name, on the end of the meter, in simple lettering, later a flowing script is used.

Before 1900 the manufacturer was R. Field & Co. From 1900 it was made and sold by the Watkins Meter Co. which took over the 'goodwill, stock and book debts' of the exposure meter side of R. Field. The cost in 1890 was 15/- later this was increased to 21/- and from the mid 1920s the price was 30/-. A model in magnalium rather than brass was also produced, probably until around 1917.

Watkins Calculation
The Watkins meters, the Standard and later Bee models, used sensitive paper to measure the light falling on the subject and used that value in a simple calculation of D/P x A = E to give the required exposure time. On the Standard the calculation was made by setting the rings on the barrel of the instrument.
  • A is the actinic value in seconds and is the time taken for the sensitive paper to darken to a standard tint.
  • D is the diaphragm measured on a Watkins scale, where f4 = , f5.6 = , f8 = 1 and so on.
  • P is the plate speed measured in Watkins units.
The values were chosen such that a plate of speed P1 with an aperture of D1 (f8) needs 2 seconds exposure under a full mid-day summer sun. In the same conditions it would also take 2 seconds for the sensitive paper to darken to the standard tint. The P value was derived from actual tests on plates and a Watkins Speed list was regularly issued with up-to-date values. Like H&D values the Watkins value was inversely proportional to the required exposure time. In practice the diaphragm ring was marked in f or US values rather than the Watkins value.

A subject scale, S, is sometimes present, the neutral value is S100 other values such as S25 (snow or sea scenes) reduce the exposure by , S50 (open landscape) reduces the exposure by and S150 increases the exposure by .

An F scale is present on Enlarging models, this takes into consideration the effect of bellows extension when copying in the camera and enlarging from a negative onto paper. For copying where the image is smaller than the original, the F scale shows the distance of the subject from the lens in focal lengths i.e. distance/focal length. For enlarging (greater than same size) the scale shows the distance of the printing paper from the lens in focal lengths.

As with other actinometers the reading is taken from the position of the subject. A pendulum is attached to the meter and measures in seconds.

References & Notes:
BP 1388/1890. BJA 1892, p. 106. BJA 1901, p. 1314. BJA 1902, p. 1310. BJA 1917, p. 9. PA 1891, pp. clxx, 418. YBP 1895, p. 89. Watkins Manual 1911. Butcher's British Cameras, 1924, p. 115.

Watkins Junior

1893

R. Field & Co.

Birmingham

England

Meter Type:
Actinometer.

Calibration:
Plate speed: 1 - 200 Watkins. Shutter speed: 1 - 900 (1/1000 - 900/1000). Aperture: f4 - f64.

Attributes:
Actinic value: 2 - 500.

Identification:
From the back the scales are P D A E.

With:
Instructions. Relative Speed List (1 Apr 1896, price 2d).

This is a simplified version of the Watkins Standard. The subject scale of the Standard is replaced by a table on the base of the meter. There is no cap or pendulum. The price was 7/6. The Junior was withdrawn probably around 1902 when the Bee was introduced.

In use the P index is set to the plate speed and the D index is set to an aperture. The actinic time then points to the exposure time.

References & Notes:
BP 14364/1893. BJA 1894, p. 832. BJA 1900. YBP 1894, p. 539.


Company Details:

Watkins Meter Co.

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