Figure B-9. Conjugate focal points (conjugate foci).

TM 9-258

Constant deviation - A certain amount of deviation

Convergent lens - See converging lens.

Converging lens - Also known as convergent lens,

given to the line of sight or optical axis of one of the

internal telescopic systems of a range finder in order that

positive lens, convex lens, collective lens. A lens that will

the correction wedge may adjust the system by supplying

converge light. One surface of a converging lens may be

a plus, neutral, or minus correction, as required.

convexly spherical and the other plane (planoconvex),

Converge - As applied to the eyes or binocular

both may be convex (double convex) or one surface may

optical instruments, to direct them so that the two lines of

be convex and the other concave (convexo-concave

sight meet at a common focus and form an angle. To

meniscus converging). A converging lens is always

direct light rays or lines to a small area.

thicker at the center than at the edge (fig B-10).

Convergence - See angle of convergence.

Figure B-10. Converging lenses.

B-9