AMATEUR PHOTOGRAPHY. 



I41 



The cluck can Hot be seen in the picture, 

 being covered by the splash made in the 

 water by the shot. The camera has recorded 

 this splash along with some of the feathers 

 shot from the fowl. The method of secur- 

 ing the effect of the shot was counting from 

 one to 3, having it understood that when 

 3 was called the shot was to be fired and 

 the exposure made at the same time. There 

 is no flash from the gun, due to the use of 

 smokeless powder. 



''Whose Flush?" was made with a Pony 

 Premo camera No. 6, 6y 2 x.8 l / 2 Plastigmat 

 lens on a Seed portrait orthopaedic plate and 

 printed on platinum paper; exposure, 1-25 

 second. 



Both dogs have found the same bird, 

 having approached from opposite direc- 

 tions. The dog on the right of the pic- 

 ture is too near the bird to take proper 

 position, due to the wind being from him 

 to the bird, but both were held in position 

 several minutes until a tripod camera could 

 be placed to show both dogs to best advan- 

 tage. By drawing a line from the nose of 

 each dog the position of the bird may be 

 located in the clump of dried grass between 

 them. 



"Return of the Fishermen" wa? made 

 with a Century Grand Sr. Special camera, 

 5x7, fitted with a 6^x8^2 Plastigmat lens, 

 exposure, 1-120 second. This picture was 

 made at Holly Beach, N. J., and shows the 

 Scandinavian fishermen, who live there in 

 considerable numbers, and the style of 

 boats, etc., used by them in securing a live- 

 lihood by sea fishing. They frequently go * 

 out 10 to 15 miles in these little launches. 

 To watch them going or returning is ex- 

 tremely interesting, there being as many as 

 40 or 50 boats with 2 men to each boat, 

 and usually all leaving or returning within 

 an hour. Their wives and children are fre- 

 quently grouped on the beach, awaiting 

 their arrival to see the result of the day's 

 work and welcome their return, the fam- 

 ilies adding interest to the scene. 



U. C. Wanner, West Phila., Pa. 



I made the photo of the bear in the 

 woods on the head of the East fork of the 

 Yellowstone river in the Park. I was 

 going into Gardiner by way of the old Cook 

 City trail, with pack outfit. 



I do not believe this bear was any tamer 

 than any bear outside of the Park, as he 

 was 40 miles from the nearest hotel, and 

 was a genuine silvertip. I have never seen 

 a large silvertip near a hotel. 



The photo was made about 5 o'clock in 

 the afternoon, in July last. I had noticed 

 some eagles soaring about the mouth of a 

 small canyon as I was making camp, so I 

 took my camera and went up to see what 

 they were eating. They had the carcass of 

 a calf elk nearly eaten, They seemed tame, 



and I hid near the bait, thinking to get a 

 snap shot at them if they came back soon. 

 In about 10 minutes I saw this bear coming 

 down the side of the canyon, straight for 

 the bait, which lay in the lower end of a 

 small park. I slipped around near the 

 upper end of the park and hid in some 

 thick young pines at the edge of the 

 opening. When he came to the park he 

 stopped and looked around awhile, then 

 started to the bait, but the instant he got 

 wind of me he stopped and threw up his 

 head to smell, as shown in the photo. I 

 had no more than pressed the bulb than he 

 turned and shot into the timber on the other 

 side of the park. He had not seen nor 

 heard me ; the wind was all he wanted. 



The distance of the bear from the 

 camera was 18 or 20 paces ; stop 16 ; time, 

 .1-50 of a second, if I remember rightly. 



N. W. Frost, Cody, Wyo. 



INFINITY FOCUS. 



It is frequently useful to know the dis- 

 tance at and beyond which all objects will 

 be in focus when usinar a lens of known 

 focal length and a given stop. To obtain 

 the requisite information most photograph- 

 ers have recourse to the published tables, if 

 they are at hand, but a simpler method con- 

 sists in marking each lens with its constant, 

 which, divided by the f number of the stop, 

 gives the so-called infinity focus or distance 

 beyond which all objects- will be in focus. 

 The constant of any lens is obtained thus : 

 Let fa = focal aperture or stop, 



F = equivalent focus of lens, in 

 inches. 



K = required constant ; 



F 2 xl00 



rp, or — = infinity focus in feet 



Then:— f ax !2 fa y 



and Kr=F 2 x8.33. 



. The following is a list of constants cal- 

 culated for a confusion disc of 1-100 inches : 



Equivalent focus K. Equivalent focus K. 



of 





of 





s in inches. 



lens 



in inches. 





3- 



75 



6-5 



352 



35 



102 



7.0 



408 



4.0 



133 



7-5 



469 



4-5 



168 



8.0 



533 



5-o 



208 



8-5 



602 



5-5 



252 



9.0 



675 



6.0 



300 



10. 



833 



Example : 



Required, constant and infinity focus of 6 



inch lens at f6. 



K = F2 x8"33=(6x6x8"33) 299*8 (say 300). 



K 300 



Infinity focus — = == 50 ft. 



fa 6 



The infinity foci for other stops will be: 



Stops f6 f8 fix '3 fi6 f22"6 f32 f4 



Infinity given in feet 50 37'$ 265 1S7 i3"3 93 6' 1 



— The British Journal of Photography, 



