APPENDIX. 



When photographing without microscope, and 

 using a lens in the adapter on front of camera, 

 the following rules will be useful. 

 To FIND MAGNIFICATION WITH GIVEN CAMERA 

 LENGTH AND Focus OF LENS 



Divide the length of camera by the focus 

 of lens, and subtract one from the result, 

 which will give the enlargement in diameters. 



WITH GIVEN Focus TO FIND CAMERA EXTENSION 



FOR REQUIRED MAGNIFICATION 



Add one to the number of diameters 

 wanted, and multiply by the focus of lens. 



TO FIND WHAT FOCUS LENS IS REQUIRED FOR 

 GIVEN MAGNIFICATION AND CAMERA LENGTH 



Add one to the number of diameters 

 wanted, and divide the camera length by 

 this number, which will give the focus of 

 lens required. 



NEGATIVE ENLARGING. 



If for exhibition or other purposes it is desirable 

 to have a print on a larger scale than usual, the 

 following formula will enable one to fix the relative 

 distances between the negative and lens, and 

 bromide paper and lens. In all cases the size of 

 the enlarged picture bears the same proportion 

 to the size of negative that the distance of the 

 enlarged picture from lens bears to the distance 



