Part of an ERS
(es) and incorporating a colorframe
holder. Hard or soft focus is achieved by moving the lens tube forward or back within the barrel
. On many modern instrument
s, the lens tubes are interchangeable and available in 5°, 10°, 14°, 19°, 26°, 36°, 50°, 70°, and 90° sizes.
A 19° lens tube.