The illustration of putting lenses in front of the eye. The focal point of the image is reflected into the eye. The focal point in the lens will end past the eye, creating a blurry image.

Optical Position and Size of Image Through Lens in Front of Eye

The illustration of putting lenses in front of the eye. The focal point of the image is reflected into…

"If y be the object the image appears to a normal eye situated behind the system L with passive accommodation at a very great distance under the angle w'. Since H' P= F O, = y, from the focal length of the simple microscope is the image side focal length." —Encyclopaedia Britannica, 1910

Optical Position and Size of Image Through Magnifying Glasses

"If y be the object the image appears to a normal eye situated behind the system L with passive accommodation…

"The intersection of the principal rays in this case lies in the middle of the entrance pupil or of the exit pupil. By head and eye motion the various parts of the whole field can be viewed one after another." —Encyclopaedia Britannica, 1910

Optical Position of Diaphragms using Lens

"The intersection of the principal rays in this case lies in the middle of the entrance pupil or of…