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.

具端着丝头(注:我猜是类似于针孔头吧)具有阔之景深，以具端着丝头，你能头不同距离之目标物成像和保持目标物在焦。