Through- The-Aperture
Electric Eye Exposure Measuring:
Perfect, Automatic Exposure for
All Lighting Conditions
Exposure measuring with any of the Autop ak-
8 D series cameras is fully automatic, con-
sistently accurate, and an entirely new
Super-S concept. Many of the same tech-
nological and electronic concepts used in the
Minolta Space Meter, carried by America's
Apollo astronauts, have been incorporated in
the exposure measuring system of the new
movie cameras. These advances, however,
do not just represent mere modifications of
old concepts, but are part of a new exposure
measuring technology designed especially
for these cameras. The result is an unusual-
Iy accurate means of measuring light auto-
matically for all moviemaking situations.
No matter what the lighting condition, the
taking lens of your camera automatically
TO VIEWFINDER
MASTER
~H~IT~Ft-t---=~~Tt-~~~i+i
FILM PLANE
z
LENS
CdS CELL
and continuously adjusts itself for accurate
exposure. The system ultilized is called
"TTA," or "through-the-aperture;" and it
differs from the common through-the-lens
system insomuch as it measures light
after
it passes through lens aperture. For corn-
parison, the conventional TTL system rnea-
sures light after it has passed
only
through-
the- lens.
Each Autopak-B D camera employs both a
CdS (cadmlurn-sulfide) cell and unusual
servo mechanism circuit for its through-the-
aperture electric eye exposure measuring.
And since this system permits the measure-
ment of light after it passes through the
half- mirror of the finder assembly and the
aperture, it is able to measure light having
the same characteristics as the true image-
forming light that strikes the film plane.
Thus when the brightness of this image,
forming light varies even a small amount
this variation is "signalled" back to the
bridge circuit in the electric eye system to
control the lens opening automatically. All
light reaching the film plane is controlled to
maintain the same brightness, and to insure
exact exposure at all times. Opening and
closing of the lens aperture is also controlled
by this unique system, and all cornpens a-
tions for frame speed, focal length, zooming
and filter variations are made automatically.
Because this Minolta electric eye system
utilizes a servo unit connected with the
bridge circuit, use of a separate mercury
battery is unnecessary, nor is the system
affected by voltage fluctuations.
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