| 摘要 |
PURPOSE:To continuously vary observing magnification of an eyepiece to about 40 times, by constituting a lens space of a lens group of such 2 groups as a negtive lens group and a positive lens group which can be varied, in an eyepiece optical system in a wide angle objective lens system and a wide angle endoscope optical system containing an image transfer element. CONSTITUTION:An image h3 of an object to be photographed is transferred to its image formation surface 3 throgh an image transfer element 4, and this image is observed by an observer 5 in an exit pupil distance L through a positive lens group 2 and a negative lens group 1. In this case, the positive lens group 2 and the negative lens group 1 are constituted so as to satisfy the condition of 0.4<f1/L1<4.0:0.4<1f2/f11<4.0. As a result, a composite focal distance of the eyepiece is varied continuously by varying a space d2 between the image formation surface 3 and the positive lens group 2, and a space d1 between both lens groups 2, 1, and the magnification can be varied continuously up to 20-40 times as observing magnification, without always out-focusing the image h3 formed on the image formation surface 3. |
