108 



C. A. Steinheil Sohne. Mtlnchen. 



Fig. 5. 



Fig. 7. 



Set of 4 achromatic land- 

 scape lenses of equal aperture 

 (23 millimeter) but different focal 

 lenghts capable of combination in 

 a common mounting fitted with 

 iris-diaphragm. 



Series V. Wide Angle Apla- 

 natic Lenses for architecture 

 and landscape with relative aper- 

 ture f/20 to f/25, angle of field 

 about 100. 



In this lens definition, depth 

 and angle of field have been 

 greatly increased at the expense 

 of rapidity. 



Series VI. Wide Angle Apla- 

 natic Copying Lenses, similar to 

 series V in point of rapidity. 



By uniting greatest possible uni- 

 "form definition and brightness with 

 flatness throughout the extended field 

 this type is particularly adapted for 

 copying maps, pictures and engra- 

 vings and for photo -mechanical pro- 

 cesses. 



Prisms. 



For directly producing so-called 

 reversed negatives for photo -me- 

 chanical printing processes wide 

 angle aplanatic copying lenses are 

 principally used in combination with 

 rectangular prisms with silvered 

 hyp o tenus e surface . 



Fig. 



