Objective lens system for microscopes

An objective lens system for microscopes comprising a first cemented doublet component comprising a plano-convex lens element and a meniscus lens element having a strongly concave surface on the object side, a second meniscus lens component, a third cemented component comprising a positive lens element, a negative lens element and a positive lens element, a fourth cemented component comprising a negative meniscus lens elements, a biconvex lens element and a negative lens element, and a fifth cemented doublet component and a sixth cemented doublet component respectively having strongly concave surfaces opposite to each other, said lens system being so designed as to satisfy the following conditions (1) through (6):

• -0.1<f/f.sub.2 <0.05 (1)
• -0.1<f/f.sub.B <-0.07 (2)
• 1.75<n.sub.2 ( 3)
• 29<.nu..sub.5 <45 (4)
• 60<.nu..sub.6,.nu..sub.8 ( 5)
• d.sub.16 <1.2f (6)
• wherein the reference symbol f represents focal length of said objective lens system as a whole, the reference symbol f.sub.2 designates focal length of the image side lens element of said first lens component, the reference symbol f.sub.B denotes composite focal length of said fifth and sixth lens components as a whole, the reference symbol n.sub.2 represents refractive index of the image side lens element of said first lens component, the reference symbols .nu..sub.5 and .nu..sub.6 designate Abbe's numbers of the middle negative lens element and the image side lens element respectively of said third lens component, the rererence symbol .nu..sub.8 denotes Abbe's number of the middle positive lens element of said fourth lens component and the reference symbol d.sub.16 represents airspace reserved between said fifth and sixth lens components.