Abstract: The present invention relates to a photographic apparatus comprising a photometric system which can tolerate a wide range of change in contrast. This photographic apparatus attains, at least, a state in which an image from an optical instrument such as microscope can be photographed and a state in which the light intensity of the image formed by the optical instrument can be measured by the photometric system utilizing a light separated from incident light. This photometric system comprises a plurality of optical systems respectively having magnifications different from each other and a photosensor having a light receiving surface defined by a plurality of light intensity detectors, wherein these plurality of optical systems and plurality of detectors are intentionally selected so as to change the range of measurement of an image formed on the light receiving surface of the photosensor.

Abstract: A condenser lens system to collect light from a light source to illuminate a sample, which comprises in a named order from the light source side, a front group of positive refracting power having at least one lens and a rear group of positive refracting power having at least a positive lens for liquid immersion located closest to the sample, the positive lens for liquid immersion having a flat surface on the sample side.

Abstract: A differential interference microscope which includes a light source, a condenser optical system for condensing beams of light from the light source and illuminating an object with the beams of light, an objective optical system for converging the beams of light from the illuminated object and forming an image of the object, a pick-up device for photoelectrically detecting the image of the object, and a contrast enhancement circuit for enhancing a contrast of the image on the basis of an output signal of the pick-up device. A first polarizing element and a first birefringent element are disposed sequentially in an optical path between the light source and the object. The first polarizing element changes the beams of light from the light source into predetermined beams of polarized light. The first birefringent element separates the polarized light into an ordinary ray and an extraordinary ray.