518 NEQRETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., 



PHOTOGRAPHIC LENSES AND PRISMS 



MADE BY 



C. A. STE1NHEIL SOEHNE, MUNICH. 

 Sole Agents NEGRETTI AND ZAMBRA, LONDON. 



NOTICE. This List is a translation of Messrs. Steinheil's Catalogue. The 

 exact equivalent focus is not guaranteed, as differences in refraction and in the 

 thickness of the lenses have to be corrected. 



N. and Z. will supply any instrument of C. A. Steinheil Soehne's make, at their 

 catalogue prices, plus the carriage expenses from factory. 



In order to meet the various requirements and to ensure in each special case as 

 perfect work as possible we make lenses of different constructions. 



The present catalogue comprises six different classes of photographic lenses 

 the capabilities and object of which are given in the order of their respective 

 rapidities. 



Departing from the order observed in our former catalogue, the lenses are not 

 numbered consecutively in the present one, but are divided into Series. Each 

 series commences with No. 1 and continues upwards. To avoid errors it is necessary 

 in ordering to quote both the No. of the Series and the No. of the lens in the present 

 catalogue. 



To facilitate finding the distances of the subject and also of the focussing 

 screen (ground plate) from the lens in reducing or enlarging, we have compiled 

 tables which are sent with every lens. 



Our different Antiplanets and Aplanats are free from disturbing reflections, 

 and thus enable their employment for all purposes in the open air and for taking 

 strongly illuminated subjects without producing flare or light spots. They are 

 strictly corrected for spherical errors and chemical focus, and they give evenness 

 and correctness of lines (without distortion) combined with equality of definition 

 over the whole of the picture. 



In " focussing " with these lenses it is advisable to use the largest stop, even, 

 when it is intended to work with the smallest. 



We make a special point never to supply a lens which is capable of improve- 

 ment, and for this purpose we test them all before sending them away. 



The scientific basis of our establishment and the precise methods employed 

 (the same in the manufacture of astronomical and photographic lenses) enable us 

 to produce lenses of such uniform accuracy that we are unable, even with all the 

 means for rigorous testing at our command, to detect the slightest differences. 



Our photographic lenses, of which we give full description in the following 

 pages, consist chiefly of two classes, viz. Antiplanetic and Aplanatic. 



