EMI Emitron long necked television
camera tube
The EMI long necked Emitron tube circa
1937. These tubes were of the "Iconoscope"
class with the target mosaic scanned from the front. They were at the
cutting edge of pre-war vacuum technology and had a short life, anything
from a few hours to a few months.
It had a sensitivity of the order of 2500 Lux @ f3. The Emitron tube with
its spherical glass enclosing the large target meant that the lens was
a long way in front of the target and this placed constraints on the usable
focal lengths and the depth of field in particular.
Long and short neck
Emitron tubes, notes
There are some fine pictures of the Emitron tube at Giorgio Basile vacuum
tube museum.