Auteur: Dan Fromm
Date: 26-07-2004 18:13
Both lenses are mentioned in the Lens Collector's Vade Mecum:
"Perfac f6.3/f8 It was made as two series:
(a)f6.3 for 3.0in for 3.25x2.25in, 3.5in for 3.25x2.25in, 4.0in 3.5x2.5in, 4.9in for 1/4plate, 5.3in for 1/4plate, 6.0in for 5x4in, 6.5in for Postcard, 7.5in for 1/2plate, 8.5in for 7x5in, 10in for 1/1plate,
and as (b)f8.0,12.25in for 10x8in, 14.5in for 12x10in, 18in for 15x12in and then to 30in. Again the suggestion is 6in for 5x4.
It was listed in B.J.A. 1921, p802; 1924, and 1925, p782advert. This list was unchanged into the late 1930's. Shorter foci were aimed at folders such as the Carbine, ICA, Kodak, and the longer ones at field and stand cameras. A modern notice is B.J.A. 1961, p216. It seems to be the least known of the three Q15 [tessar] types even though it may well be optically the best due to the limited aperture which makes the corrections easier and limits flare."
"Serrac as prewar,ctd. f4.5 These have been noted postwar in 2-18in. in 18 foci but by 1962 they was 'in a full range from 2-8in' including Compur shuttered models. An especial claim was that the rear glass was about the same diameter as the front giving more even illumination and that while flare was kept to a minimum, there was a generous coverage for use of rising fronts, eg on MPP and Gandolfi cameras. It was suggested to use 6in for 5x4, and 5.5in cost £36.00. A f4.5/7in in a Compur EX/CII/5 was noted in B.J.A. 1956, p217.at No471,581. The iris closed to f22, or less, and Dallcoated.
These can be excellent! Layout 023. [tessar]"
Cheers,
Dan
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