Abstract: A microscope having little damage such as deformation, discoloration or the like given to a sample is disclosed. This microscope comprises an illuminance reducing unit for reducing illuminance of an illumination light on the sample. Assuming that a time width where illuminance is at a level enough for displaying an image of the sample is TF, a time width where illuminance is lower than the level enough for displaying an image of the sample is TN, and a value &agr; is as follows: &agr;=TF/(TF+TN) the value &agr; is changed according to a velocity of a stage or the like. A monitor displays a still picture of the sample for a period of TN, the still picture being one before the time width TN.

Abstract: A microscope having little damage such as deformation, discoloration or the like given to a sample is disclosed. This microscope comprises an illuminance reducing unit for reducing illuminance of an illumination light on the sample.

Abstract: Distance measurement apparatus comprises a collimating optical system and an optical path divider. The collimating optical system contains an objective lens, a focusing lens and an eye-piece arranged in the named order. The optical path divider is disposed between the objective lens and the focusing lens. A reflecting member is provided on the optical path branched by the optical path divider. The reflecting member has first and second reflecting surfaces which intersect each other at right angles. A light source supplies a beam of transmission light to the first reflecting surface. A photo receptor receives the beam of light reflected by the second reflecting surface. An auxiliary lens is provided between the optical path divider and the reflecting member and cooperates with the objective lens to form an afocal system.