Photography in the Studio and in the Field / A Practical Manual Designed as a Companion Alike to the Professional and the Amateur Photographer

by Edward M. Estabrooke

Fig. 9.

Fig. 10.

Probably the two greatest rivals to the Dallmeyer Wide Angle Lens are the Actinic Doublet of Ross (Fig. 9), and the Steinheil Aplanatic (Fig. 10). The Ross Doublet consists of a crossed crown lens, cemented to its correcting flint lens, which is a crossed concave, the whole forming a deep meniscus the focus of which is equal to the back combination or about double that of the equivalent focus of the complete instrument, the posterior meniscus combination consists of a meniscus crown lens cemented to a concavo-convex flint lens. The two combinations are mounted rigidly with a rotating disk of p96 diaphragms or stops placed midway between the lenses.

The Steinheil consists of a front and back corrected combination of precisely the same shape, mounted rigidly and having a rotating disk of apertures placed midway between the lenses.

These are three distinct types of view lenses of wide angle, and a comparison of the diagrams will show the wide difference in the construction of the two latter from the Dallmeyer; and while they stand unrivaled for the perfection and beauty of their work, which is about equal, the Dallmeyer obtains a great advantage over the others in the thinness of its lenses, which enables it to work with greater rapidity, and indeed it has been used with great success with the drop-shutter for photographing moving objects and other similar out-door work.

FIG. 11.

While the possession of a wide angle lens is indispensable in the varied selection of out-door subjects, yet for many purposes it has been found they are unsuitable; and to meet this want Mr. Dallmeyer has constructed a modification of the wide angle, which he calls Rapid rectilinear. Its construction is shown in Fig. 11. The lenses of the front and back combination have the same general form as those of the wide angle, but they are of smaller diameter, being constructed for angles of 60 to 70 degrees only. It is four times as rapid, and is in fact an aplanatic and symmetrical lens, and may be regarded p97 as the most perfect lens extant. As it admits of the use of a larger aperture it is well adapted for interiors, where there is space for its use, and for almost every purpose of out-door photography, requiring short exposure and no greater angle.