focus recompose error graphs

How much error do you make when you focus recompose?

Keep in mind:

1. Depth of Field can mask any error.

2. The horizontal angle of view of a standard lens (50mm on 24x36 format) is 40°

3. The maximum recompose angle is half of the lense's FOV.

4. It is unusual to recompose by more than a third of the lens's FOV.

5. to recompose by 40° you have to use a superwide lens (18mm on 24x36) and recompose from centre to edge.

 

This is the Matlab code. It is clumsy, but anyway:

 

close all

clear all

clc

 

recomposeanglevec=linspace(0,40,41);

focusdistancevec=linspace(1,10,10);

 

count1=0;

for x=recomposeanglevec

count1=count1+1;

recomposeangle=recomposeanglevec(count1);

count2=0;

for y=focusdistancevec

count2=count2+1;

focusdistance=focusdistancevec(count2);

focuserrormat(count1,count2)=focusdistance-focusdistance*cos(recomposeangle*pi/180);

focuserrorrelativemat(count1,count2)=focuserrormat(count1,count2)/focusdistance;

focusdistancemat(count1,count2)=focusdistance;

recomposeanglemat(count1,count2)=recomposeangle;

end

end

 

figure

mesh(focusdistancemat,recomposeanglemat,focuserrormat)

xlabel('focus distance [m]')

ylabel('recompose angle [°]')

zlabel('focus error [m]')

grid on

colorbar

 

figure

mesh(focusdistancemat,recomposeanglemat,100*focuserrorrelativemat)

xlabel('focus distance [m]')

ylabel('recompose angle [°]')

zlabel('relative focus error [0..100%]')

grid on

colorbar

 

figure

plot(recomposeanglemat(:,1),100*focuserrorrelativemat(:,1))

xlabel('recompose angle [°]')

ylabel('relative focus error [0..100%]')

grid on

 

Done