THE CAMERA 365 



your plate filled at a greater distance." focus there is great depth. It is un- 

 I don't care how you do it and I don't fair to compare depth of a long focus in 

 care how many of these fanciful fac- this example, because the long focus- 

 tors you use to explain it, the fact re- cannot get that field of the room. The 

 mains that experience teaches, "The comparison should be made on a sub- 

 longer the focus the greater the depth," feet ivithin the scope of boili lenses, 

 while the books teach the converse, and the basis should be the same 

 Suppose I wish to fill a 5 x 7 plate with sized image on the ground geass. li 

 the picture of a house taken at its such a comparison is made the long 

 greatest depth — that is, diagonally. If focus has the greater depth, and far 

 I follow the instructions 'of the books, better perspective, without distortion 

 I put on the camera the shortest focus of near parts. My advice to the cam- 

 lens, but every commercial photogra- erist is to USE as long Focus as possible 

 pher knows that that will distort the for greatest depth and perspective, pro- 

 picture, and that if the plate is to be vided the longer focus will take in the 

 filled the lens must be stopped down field desired. Of course, if the longer 

 very much and as a consequence fore- focus will not take in the desired field 

 ground or background or both will be then there is no comparison. Most 

 out of focus. Every one with conver- lenses are divisible — even the cheaper 

 tible lenses, and with a battery of dif- rectilinear are so. Where speed is not 

 ferent lenses of different foci, knows essential, and the longer focus will take 

 that in actual experience he would put in the desired field, the best depth is 

 on his long focus and get as far away obtained by using the half lens. There 

 from that house as the situation w r ould are many cases in photography where 

 permit. The long focus would bring the half lens is better than the whole, 

 the house up to him, and give a depth Yet I find many amateurs with divisi- 

 that would not be a distortion as would ble lenses and plenty of bellows who 

 be the depth obtained by a near view, do not realize this advantage of bet- 

 with lens stopped down. ter depth and perspective of the half 



Of course, I understand that if one is lens witn double length of focus, 



in a room and wishes to get as wide If you are to photograph a house, 



a field as possible with correct depth tree or stone wall, anything not requir- 



one must use a small aperture and a ing speed, get away from it and bring it 



short focus. But suppose instead of up to you by the half lens, 



filling the plate with the entire room, Get the long focus habit— where it 



he wants to fill the plate with the din- w ju apply. 



ing room table. Would anv one in his T , ^ / . , , , .;, 

 senses use a short focus to get the front JV beginnei -is puzzled by either 

 and back of that table into focus at the he £ re ? oin § ° r ^ ex P lanatlon ln the 

 same time? Would not any one with h andb °oks, if any beginner cannot un- 

 common sense use just as long a focus d u erstand > he m W r ™ di }y demonstrate 

 as possible, and do it from the part of the incorrectness of the general un- 

 the room most distant from the table? <l uahfie u d statement that short focus 

 In comparing depth of focus with gives the greatest depth, by holding up 

 length of focus, the whole question his forefingers about six inches from 

 must be taken into consideration. One each other and m lme wlth the eve - 

 must include the sice of the field to be Hol(1 the two hands so that the nearest 

 put on the plate. The trouble seems to finger is from eight to ten inches from 

 come about in an unfair comparison, the eye. Now try to focus your eyes 

 We think of a large field for the short for depth. Look first at the near fin- 

 focus and a smaller field for the long ger. The farther finger is in a haze, 

 focus. A comparison of depth is un- Look then at the farther finger, and the 

 fair, because the long focus in many near finger is in a haze. Now hold the 

 cases cannot do it at all, as, for 'exam- two fingers at the same distance apart 

 pie in photographing the interior of a and as far away as you can reach. Is 

 room with a wide angle lens of short it not evident, as you look at one fin- 



