THE DEVELOPMENT OF THE PHOTOGRAPHIC OBJECTIVE 



53 



Beck: Biplanat, Symmetrical, Portrait Biplanat 



Bert hiot : Perigraphi que 



Busch: Rapid Symmetrical, Rapid Aplanat, Wide-angle Aplanat 



Dallmeyer: Rapid Rectilinear 



Fleury-Hermagis : Eidoskop 



Groerz: Lynkeioskop and Paraplanat 



Hartnack: Pantoskop 



Ilex: Convertible Rapid Rectilinear 



Meyer: Aristoplan and Aristoplanat 



Rodenstock: Recti-aplanat, Wide-angle Aplanat 



Schulze: Orthoskop and Sphariskop 



Steinheil: Aplanat 



Suter: Aplanat 



Voigtlander: Euryskop 



Wollensak: Versar 



Wray: Platystigmat 



Also the very interesting series of Steinheil lenses, in which an attempt was made to 

 reduce the Petzval sum by using old glasses, has been omitted. They are given in 

 Table IV: 



Most manufacturers have made portrait lenses of the Petzval type or one of its 

 modifications. These are now largely but not entirely obsolete. Table V gives a 

 list of some of them : 



Table V. — Portrait Lenses 



Principal Types of Anastigmat Lenses. — In Table VI, which follows, the lenses are 

 given in alphabetical order under each manufacturer. A number immediately after 



