DEVICE FOR CORRECTING FOCUS POINT AT MACROPHOTOGRAPHING OF AUTOFOCUSING CAMERA

摘要

PURPOSE:To improve the accuracy of focus point correction by providing a mask which has an aperture center on the outside of the optical axis of a light receiving lens and prism which refracts a ray for distance measurement toward the light receiving lens to the front face of the light receiving lens in such a manner that the mask and prism advance at the time of macrophotographing. CONSTITUTION:The mask 9 which has the aperture 10 center on the outside of the optical axis of the light receiving lens 6 and the prism 8 which refracts the ray for distance measurement past the aperture 10 of the mask 9 toward the optical axis side of the light receiving lens 6 are provided to the front face of the light receiving lens 6 of the above-mentioned optical system for distance measurement to receive the ray for distance measurement from a subject in such a manner that the mask and the prism advance at the time of the macrophotographing. The focus point correction at the time of the macrophotographing is executed by using the ray which enters the lens 6 from the outside of the optical axis and is emitted from the outside of the optical axis as the ray for distance measurement. The accuracy of the distance measurement is thereby improved with the simple constitution without increasing the size of the prism.