Lens identification

[Simon Benton]

From an old photography studio I bought a Graflex 4X5 SLR that included an 8 3/4 Verito and a lens that appears to be off a WWII aerial camera. It is marked Made in England AM No 14A/1727 and on the front lens barrel is engraved 8 inch f5.6 Anastigmat No 276703. The lens consists of two air-spaced doublets of which the two outer ones are double convex, and the two inner ones are double concave. There are 4 strong reflections in the front and 4 strong reflections in the rear.
I have researched on the web and am of the opinion it is an Aviar but can find nothing to indicate it was made by Cooke. Can anyone shed any light on this. Casts a lovely image on the ground glass and covers 5X7.

[Steven Tribe]

I don't think anyone has a list of all the various Air Ministry contract numbers.
If there is no identification (TTH or other letters), then it is probably made to TTH's design by one of the many subcontractors in the hectic decentralisation efforts to avoid capacity loss due to the luftwaffe. Very popular items in post-war surplus sales.

[cdholden]

From the Cooke Optics website, :
"The Cooke Aviar Series II f/4.5 and Series IIIB, f/6 and f/6.3 lenses are of what lens designers call the dialyte type of lens construction. This consists of two air-spaced achromatic doublets, the two outer ones double convex, and the two inner ones double concave, with no cement or coatings to become discolored with time."

No mention of anything f5.6. Maybe a Dallmeyer lens? I've seen mention of Dallmeyer lenses with AM markings... or were they just contracted by TTH to build them to spec?