45, COKNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 



519 



ANTIPLANETIC LENSES. 

 Patented in Germany (No. of Patent 16354), England and America. 



By means of these recent combinations, we have succeeded in correcting to a 

 considerable extent the hitherto greatest defect in Photographic Objectives, viz., 

 " Astigmatism," and with the consequent rapid decrease of definition from the 

 centre to the margin of the picture. 



This advantage we have obtained by designing a special combination, differing 

 widely from the usual forms. It consists of two entirely different halves, each of as 

 great and diametrically opposed errors as possible. The foci are therefore different, 

 and whilst the anterior lens has a shorter focus than the whole objective, that of 

 the posterior lens is negative. 



The above arrangement enables us to produce an objective which, whilst 

 retaining the qualities of a good instrument, embodies the additional advantage of 

 having " less astigmatism," by which greater sharpness and depth are produced and 

 distributed thereby more equally over a larger and strictly even picture, before 

 any decrease in definition is perceptible. Illumination, too, is more evenly dis- 

 tributed in consequence of the lenses being proportionately nearer to one another. 



The perfectly correct delineation produced by these " Antiplanets," renders 

 them particularly suitable for enlargements. 



If small and very sharp originals are taken, and subsequently enlarged, depths 

 are obtained, which, in larger pictures taken direct with the same amount of 

 light would be unattainable ; for this purpose (which probably will play an im- 

 portant part in photography), the Antiplanets are specially suitable. The same 

 objective may be employed for direct work, and for enlargements, but in the latter 

 case, the front lens of the Antiplanet should be turned towards the enlarged picture, 

 and the back lens towards the object to be enlarged. 



This construction is designed for strictly even and correctly delineated pictures, 

 and all tilting of the Camera should be decidedly avoided, and a movable lens used 

 instead. 



Note. TheJLensesof Series I., II., III., IV.,' and VI., have "Waterhouse Diaphragms. 

 V., have Rotating Diaphragms. 



3161 



SERIES No. 1. 

 ANTIPLANETIC LENSES FOR PORTRAITS. 



The rapidity is the same as in the usual Portrait Objective, but there is more 

 equality in the distribution of sharpness and illumination over the picture, and 

 greater depth. These advantages combined render the lenses of this series specially 

 suitable either for Portraits or for enlargements. They consist of two pairs, of 

 which the anterior is cemented as positive, and the posterior is separated from the 

 former, and negative. 



Special Quotations for Larger Sizes. 



