226 



Till'. (U'IDE To \ \TURE 



THE PROTAR LENS PHOTOGRAPHED ITSELF. 

 Each half "took" the other, and then the whole itself in a mirror. 



1 find it more and more convenient 

 to use the rear combinations alone. 

 Tins longer focus (giving greater 

 depth on near objects) is very conven- 

 ient. The entire combination is a little 

 too short, and the front a little too 

 long, for such work, but they have 

 other uses and qualities equally advan- 

 tageous. At a very limited cost, there 

 is no one lens that I have found so use- 

 ful as this. Though tested only for 

 five by seven cameras, it has excellent 

 covering power on a six and one-half 

 by eight and one-half, and is good for 

 portraits and enlargements. My gen- 

 eral use of that combination alone can- 

 not be altogether a habit nor an idiosyn- 

 crasy : it must be that experience in 

 the great convenience has led to the 

 use. All the photographs of orchids, 

 some of them unexcelled, in the last 

 number, were taken by the lens. For 

 rapid work the Unar, made by the 

 Bausch & Lomb Optical Company, is 

 good, especially with focal plane shut- 

 ter. I do not find the Unar now listed 

 in the recent catalogues of that com- 

 pany, except in long focus for portrait 

 work. 



Of the Tessar, extensively adver- 

 tised in this magazine and elsewhere, 

 I have no personal knowledge, but 

 have been told by fellow photograph- 

 ers who have used it, especially on 

 nature subjects, that it is surprisingly 

 crisp, sharp and clear, and that it pro- 

 duces negatives of a peculiarly fine 

 quality. It is undoubtedly to be con- 

 sidered as one of the best. One of my 

 friends who is a "crank," as he terms 



it. on all kinds of photographic lenses 

 has written to me that there is a pecu- 

 liarly fine quality in the Tessar which 

 he has found in no other. But it must 

 be remembered that you cannot get 

 everything in one lens. The Celor is 

 also fine, but neither Tessar nor Celor 

 are divisible as are Protar and Dagor. 

 It is mighty handy at times, and many 

 times too, to have a lens that is divis- 

 ible for longer focus. 



The editor of The Guide; to Nature 

 will gladly give advice if you are in- 

 tending to purchase an anastigmat 

 and he will also help you to produce 

 the best possible work. Send on your 

 nature photographs for criticism and 

 suggestion. Twenty-five years' ex- 

 perience and an unexcelled equipment 

 are now at your service, free of all 

 expense. We really want to help you 

 to take better photographs. 



A Real Photograph by a "Ghost" Lens. 



"Did you ever know of a photograph 

 taken by a lens not in existence," I 

 inquired of the expert in the testing 

 department of Bausch & Lomb Opti- 

 cal Company, on a recent visit to their 

 factory. 



"Oh, yes. You mean a pin hole cam- 

 era where no lens is used." 



"No," I replied. "That is the ab- 

 sence of a lens. I mean a lens that is 

 not of glass nor of any other substance, 

 and yet gathers light rays and focuses 

 them on the sensitive plate, so that a 

 photograph is the result." 



"Explain your riddle," he replied. 



"A mirrored reflection of a lens is 



