Широкоугольный объектив для складных и карданных камер.
for wide angle work with folding and stand cameras.
Рекомендуется использовать Protar F/18 как широкоугольный объектив для архитектурных и интерьерных съемок.
The Double Protar has relative apertures of F/6.3, F/7 and F/7.7, according as to whether it is made up of two Protar lenses of the same or of different focus. Its most rapid combinations accordingly come very near to the Tessar F/6.3. It possesses, moreover, the advantage of being made up of components which may be used independently as long-focus lenses and which give sharp images at F/12.5. In many cases they are rapid enough for snapshots, and there is the further advantage that as a rule their components have different focal lengths*).
Those who wish to be able to secure the best composition of the picture, whatever the subject, and who insist on a faultless perspective and at the same time wish to take snapshots, cannot do better than provide themselves with a good camera of the selected size with double or triple extension, and furnish it with a Double Protar made up of two component lenses of dissimilar foci together with a Compur shutter. The Double Protar may then at the time of purchase or on any subsequent occasion be expanded into a veritable universal equipment by adding Protar lenses of neighbouring focal lengths and supplementing the resulting Convertible Protar Set by a wide-angle lens proper, say a Protar F/18 and, for long range work, a telephoto attachment, together with suitable yellow glass filters. Such an outfit will enable its owner to secure the most perfect results under the widest possible range of conditions