Telocentric lenses work with a wide depth of field. With a telocentric lens, you can image objects of different distances from the lens and the objects stay in focus.

着丝粒的头(注:我猜是类似于头吧)有阔之景深，着丝粒的头，你能够将由头不同距离之目标物成像和保持目标物在焦。