01-13-2014, 11:17 AM
Please tell us the axis you rotated the camera around:
A: Was it a turn round the tripod's vertical center column while the camera stayed in landscape orientation?
B: Was it a turn from landscape to portrait?
Answers for
A: no, that's not field curvature. It's simple triangulation, if you draw a line from camera to center of object (given it's a flat object and parallel to the sensor's surface) and another line from camera to the border of the subject, the latter will be longer and therefore the distance must be corrected.
B: yes, that's field curvature. Ideally, the field of sharpness would be only 2-dimensional and a very even wall, if parallel to the sensor, would be very sharp in center and border. But the normal field of sharpness is spherical because a lens without aspherical elements would only show a point or a ring of sharpness. The correction of this spherical area of sharpness into a more or less even area will be in reality a surface similar to the waves a single drop of liquid produces when falling into a volume of liquid.
Maybe that answer helps but if not, pleas clarify the term "rotate the camera" first.
A: Was it a turn round the tripod's vertical center column while the camera stayed in landscape orientation?
B: Was it a turn from landscape to portrait?
Answers for
A: no, that's not field curvature. It's simple triangulation, if you draw a line from camera to center of object (given it's a flat object and parallel to the sensor's surface) and another line from camera to the border of the subject, the latter will be longer and therefore the distance must be corrected.
B: yes, that's field curvature. Ideally, the field of sharpness would be only 2-dimensional and a very even wall, if parallel to the sensor, would be very sharp in center and border. But the normal field of sharpness is spherical because a lens without aspherical elements would only show a point or a ring of sharpness. The correction of this spherical area of sharpness into a more or less even area will be in reality a surface similar to the waves a single drop of liquid produces when falling into a volume of liquid.
Maybe that answer helps but if not, pleas clarify the term "rotate the camera" first.