Lenses with zoom function

Image an object with high resolution(letticed) at a distance of 3 to 5 m

and zoom in the lens as close to TELE as possible. Then adjust the lens

Efocus bar until the object is seen best.

Zoom in the lens as close to WIDE as possible and adjust the BACK

FOCUS adjustment bar until the object is seen best.

Repeat from toabove 2 or 3 times until the focus on the ZOOM TELE side is in line with that on the ZOOM WIDE side.

BACK FOCUS

CONTROL BAR

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