High tech cameras
also means they are heavily dependent on the raw computer power to perform their
various functions, controls and processing vast amount of data. The T90 has a pair
of electronic brains (A circuit of 130,000 thinking elements means 121 items of input
data are processed instantaneously: The Electronic Input Dial Control 121 Input Items).
Note: PLEASE USE the MAIN MAP for the viewfinder and LCD display for cross reference
in this site. Another page is also equally helpful for its layout of controls and buttons.
of the SPC that handle the TTL flash at the mirror box. - Tom Scott -
The T90 has
NO mechanical shutter to operate as a back up - just like the AE-1, AE-1 Program
or A-1 models. In fact, none of the T series models has a mechanical lever to operate,
meaning it will just fall dead when your battery runs out of power. This may seems
very uncomfortable to deal with for purist or when you are on a important assignment,
but Canon has a large following worldwide and of course, now everyone has accepted
the fact that full automation is part of the 'game' in modern photography. How does
all of these enormous amount of users' input be simplified ?
Input Dial leads to the development of Command Input Dial. Change the way how we
handle and operate a modern camera.
the innovative nature of the T90 better than its original Electronic Input Dial.
It's the optimum solution to what previously had been a seemingly insolvable problem:
how to easily control a vast amount of input data. The design practically changes
the way of how the users handle his/her photographic tools - such engineering was
influential enough to become trend setting, to be followed and copied by Canon's
competitors! Of cause, the T90's original input dial was still at its infancy and
conceptual stage during its debut. But its ease-of-use and capabilities eventually
leads to further development and upgraded into the more advanced version as used
on every Canon AF model currently available on the market. Conventional electronic
cameras used various forms of pushbuttons or slide switches, or a combination of
the two, for digital data input. Although these systems do get the job done, they
are clumsy and don't satisfy some of the photographers who prefer to think in mechanical
"analogue" terms, and prefers to use the traditional aperture ring and
shutter speed dials. The T90 combines the best of both worlds. The Electronic Input
Dial is obviously faster than previous information control systems. It easily handles
the vastly increased amount of data that modern electronics generates, like the half-step
increments between shutter speeds and aperture settings, for example. Yet it also
retains the mechanical "feel" of a rotating ring. When setting the shutter
speed, for example, to the right is a faster speed and to the left is a slower one.
You quickly get used to it. And there's no need to take your eye off the scene you
way of input may have to give way...
expect Nikon's new AF after the F5 to follow suit and it did, with the Nikon F100.
With the Electronic Input Dial, you can easily control a rather astonishing amount
of input data: The T90 has 10 shooting modes, 36 shutter speeds, 20 aperture values,
3 metering modes, 31 manual film speed settings, 12 exposure compensation settings
and 9 multiple exposure frames. Yet the dial is so naturally easy to operate that
you quickly forget just how sophisticated the system is.
The main "brain" of the T90 for all these calculations, where its micro
circuitry features 6 LSIs, 4 ICs, and a quartz oscillator (refer to illustrations
above, at top of the page). The core of this system is a dual CPU (Central Processing
Unit) configuration. The main CPU handles overall sequence control and operates at
low power, while the sub CPU, directed by the main CPU, runs at a much higher clock
speed - 1 MHz for the sub-CPU as compared to the "slower" 32 kHz of the
main processing unit. This twin-brain system allows the T90 to process a vast amount
of input information in lightning-fast real time operation. The two CPUs keep in
touch by means of a high-speed serial digital UO interface LSI. The whole circuit
maintains a volume of about 130,000 elements - about 30 times more than the Canon
A-1, and approximately 7.5 times more than the Canon T70. The main CPU handles the
LCD panel and operation sequence control for the entire camera. The sub CPU is in
charge of information display inside the view finder, algorithm calculation plus
memory after metering, and high-speed data processing for sequence control operations
concerning the 3-motor system.