varifocal erecting system(optical system provided with a means for continuously changing the magnification by changing the relative positions of the lenses)
short-wavelength cut-off filters(optical materials which are transparent throughout the ultraviolet region down to their absorption edges, below which they are opaque)
short-wavelength cut-off filters(optical materials which are transparent throughout the ultraviolet region down to their absorption edges, below which they are opaque)
photoconductive cell(it is composed of a body of semiconductor whose conductivity increases on exposure to light, plus electrodes attached to opposite ends or sides of this body)
zoom objective(the separation changes between the lens components yield a focal plane which is stationary or does not move outside the limits of depth of focus)
zoom lens(by means of internal movement of the lens components with respect to each other these lenses can be changed in effective focal length and thus vary the linear magnification)
vari-focus lens(by means of internal movement of the lens components with respect to each other these lenses can be changed in effective focal length and thus vary the linear magnification)
variable power zoom lens(providing a continuous range of magnification: by means of internal movement of the lens components with respect to each other these lenses can be changed in effective focal length and thus vary the linear magnification)