With an optical system that brings the aerial image in the focus plane into my eyes. Good for focusing, not practical for viewing large format images.
Originally Posted by pdeeh
A ground glass disperses the incoming rays, making them directly visible at the focus plan.
However the dispersion takes place around the angle of the incoming rays, and is typically not sufficient to give a bright enough image at the edges of the frame. In order to avoid to avoid bending ones head continuously from one side to the other, a field lens is used to make the outgoing rays bend towards the photographer's head. Typically these lenses are flat lenses of the Fresnell type. Also the coarseness of the ground glass is of influence: the more course the better the dispersion and the more even the illumination, but the less the resolving power and the lower the luminance.
Last edited by AgX; 01-07-2013 at 01:10 PM. Click to view previous post history.