The Wynne pre-dates the Watkins Bee meter but did not achieve the popularity of that meter. Early models had no spring in the back of the case and are without the subject guide and orange cover that protects the sensitive paper. The subject table was added in the late 1890s. Around 1897 a small black segment was added to the cover glass to protect the sensitive paper prior to exposure. In 1898 the segment was replaced by an orange glass disc mounted on the cover glass. The new cover glass was available to update older meters, as was the spring (intro. 1900) that fits into the meter case. Around 1901 the tone of the grey tint and the sensitivity of the paper was changed. The new tint was included in packets of sensitive paper. Around 1904 a US dial option was introduced and around 1910 a special dial with speeds up to 1/1000 was sold as the Infallible Snapshot Meter. A solid silver model was also offered rather than the normal nickel plated version. The aperture scale carries the value f5.6 or f5 ½, 5.6 tends to be early but not consistently so.

The price in 1900 was 7/6, this was soon reduced by a shilling but was still considerably more expensive than the Bee.

Originaly the sensitive paper was sold in sealed tins, around 1901 the paper was sold in packets.

In use the actinic value of the light is measured by the time taken for the sensitive paper to match the standard tint, the plate speed is set against this value. The shutter speed and aperture pairs can then be read on the two scales of the meter.

Slide rule model

The patent for the meter shows a watch shaped instrument and mentions that other forms are possible including one with a separate slide rule. The slide rule, which was called the Infallible, was described in the British Journal of Photography of June 1893, the article states that a separate actinometer may be used with it, though it is not clear if this was actually supplied by Wynne, certainly it was not available for review by the BJP. The slide rule comprised three columns the outer two being fixed, the inner brass strip was movable. On the right-hand column were stops, ranging from f4 to f256. The left-hand column represented the speed of plates, graduated from 'a very low degree of slowness to an almost inconceivable rapidity'. The centre column, engraved on the brass slide, had the exposure values ranging from 64 seconds down to 128th of a second. The meter was a little over 3" long and was accompanied by full directions for use. A slide rule model is shown in the Photographic Journal of May 1932 and in the BJA 1894.

The BJP of February 1894 notes that the meter has now been improved and is has the form of a pocket watch.

Dennison, Wigley & Co. was formed in 1874 when Aaron Dennison moved from America to Birmingham (England). The company continued following his death in 1895, in 1905 the company name was changed to the Dennison Watch Case Co. and survived into the 1960s.