Modern Classic SLRs Series :
Canon T90 - Concept Part III


Input dial.jpg


No one realized then the Electronic Input Dial could cast such a strong influence
on the design of the modern 35mm SLRs.

Left View.9k jpeg

Right View.10k Jpeg

The original design was inherited by the EOS models, particularly the EOS-3, EOS-1, EOS-1N/1N RS and the new EOS-1V, where they all have a strong resemblance.

The Palm Door of the side panel that housed some of the critical controls where they would not cluttered up the T90's smooth layout.

The earlier days of Contax cameras must have inspired Canon engineers in some ways when the T series cameras were introduced. The first two models, the Canon T50 (March, 1983) and the T70 (April, 1984), have a built-in winder mechanisms, but with their very plastic feel and the slow winding speed, both cameras were not that impressive as what Canon claimed. Well, the T90 was a different kind of beast all together. It has a built-in motor-drive film capable of firing at a speed of 4.5 frames-per-second (fps) and a top shutter speed of 1/4000 sec. (though moderate by current standard, but was considered "lighting fast" in those as the New F-1 only has 1/2000 sec maximum top speed) despite its very compact design. As comparisons, Nikon's FM2/FE2 models, which were the first two 35mm SLR cameras to have the top shutter speeds of 1/4000 sec and top sync speed of 1/250 sec (the FM2 first has a 1/200 sec X-sync before the later batches were upgraded to 1/250 sec), but only gave out firing rates of only 3.2 and 3.5 fps when fitted with the Motor Drive MD-12. Keeping the T90 as lightweight and lean as possible was a hurdle at first for Canon's engineers. To drive the film at the speeds wanted and maintain the fast shutter speed, a huge motor would be required, and need to be powered by at least 8 size AA batteries.

But like most innovations, the solution was elegantly simple. Although it did require some bold re-thinking. And thus, the T-90 has another 'breakthrough' its motor driven technology. This truly deserved some mentions as Canon has some energy efficiencies issue to be tackled. Nikon's F3/MD-4 combination can handle up to 140 rolls of film (AA-size alkaline) while the Canon New F-1 with its AE Motor Drive FN can only managed up to 50 rolls using carbon-zinc AA-size batteries. Thus, the T90's built-in motor drive system was actually a project to revamp the whole concept for Canon. Canon's engineers were certainly very pleased with their research on the motor drive and metering capabilities design of the T90. The front panel clearly illustrated that by putting these unique concepts just underneath the T90 emblem.

During the initial stages of designing the T90's built-in motor drive system, instead of centralizing the power system in order to generate as much power as possible, Canon engineers went the opposite direction and decentralized it. Three specifically dedicated motors would be located close to the functions they drove for maximum mechanical efficiency. This design proved to efficient as Nikon's pro AF SLR, the F4 of 1988, had utilized this concept as well In order to maintain the ultimate in reliability and versatile operation, new coreless motors had to be devised that would not draw power from each other yet in some instances would be able to work together. Eventually, a new combination of distributing loads were obtained:

One specific motor was use d to advance the film. Another charges the various mechanisms involved in actually taking the picture. And a third one rewinds the film. A built-in computer controls all three motors electronically. The result was a more efficient performance in terms of reliability and power efficiency. With the development of this unique 3-motor design came a host of equally important innovations, each of which takes advantage of the improved operability that was derived from the 3-motor system. For example, the 4.5 fps film transport speed and 1/4000 sec. shutter speed placed new demands on shutter blade construction and shutter mechanism braking devices. Specially coated duralumin shutter blades were adopted to withstand the shock created by super-fast shutter speeds. And a new two steps braking mechanism was devised to cushion the shutter blades as well.As the T90 was an extremely sophisticated auto camera, the CPU (central processing unit), the "brain" for the various complex calculations has to be redesign to handle the heavy "workloads". One result of the need to cover all the bases came out in the weighting of programming code operations. Only about 30% of the program code actually instructs a mechanism or drives an operation. The other 70% is dedicated to the unforeseen That is, it has been written solely to meet the unexpected events that might occur within the millisecond-period at circuit level.

Viewfinder.jpg (13k)
Compared with the A-1's viewfinder, the T90's was a bit more 'complicated'. But it still managed to contain all of its complexity by offering a clear, unintrusive view with its LED and LCD displayed.

Of course, like all cameras, the T90's basic operations were also sequential: the light is metered, values entered, settings determined, the shutter opened then closed, and the film advanced.

A shutter capable of operating at 4.5 fps will open and close 270 times a minute and 16,200 times an hour. Endurance testing, measured in total cycles (where most pro oriented camera are capable of handling between 100,000 and 150,000 exposures cycles with midrange cameras at around 50,000 cycles). There is no comparable figures in actual test, but Canon does claimed it exceeds the minimum endurance test of "its target" in lab test. Well, I don't think we should argue too much on these, as no one will sacrifice his own camera bodies to perform these test, as the reference point is, most of these reputable manufacturers know of what kind of environment that users like us will subject such a high performance camera like the T90 to.





The 1/4000 sec. shutter speed is possible because a new material for the focal plane shutter, the PMS (Permanent Magnet Shutter) used shutter blades made of superduralmin materials with a special coating. Moreover, the shutter is powered by a torsion spring. This spring "boost" gives the shutter its quick acceleration ability. This has made it possible to run the shutter stable at fast speeds, and to increase the curtain speed up to 3.3ms/24mm.

In order to stop the shutter blades accurately, Canon engineers adopted a highly effective two step braking mechanism. This sophisticated method combines an initial "soft" braking to begin stopping the blade and ease the shock of stopping, followed by a "hard" braking action that completely stops the blades. High-speed response is ensured by a time control magnet driving voltage boosted by a DC/DC converter (1 5V).


Note: PLEASE USE the Main Reference 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.


Prior to the arrival of another new breed of cameras, the AF types, it was safe to say, there isn't any camera that was built to be as versatile as the T90. No camera had ever combined so many sophisticated features to become so superbly operable. The physical design of the camera was treated with as much thoughtful care as its complex mechanisms and advanced functions within. Two approaches were combined into a single achievement. Industrial design was considered both as an art form and as an example of advanced ergonomics. The T90 was going to be tactilely gratifying, subtly textured, physically so beautiful. Some of its original designs has a direct impact on modern camera design and to some extend, copied and duplicated by some, that includes its own manufacturer, Canon over to the current AF bodies. The electronic data input dial, leads the way as the first 'command input dial system for current
EOS bodies. To sum it up, it is a classic modern SLR - only victimized by the arrival of the AF age and the ever changing desire of users' requirements. Short lived may be for the camera, but long lived the concept & design, the Canon T90.

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| Capabilities |

Its Metering, Exposure control, Flash photography, Viewfinder display, Film Backs, Built-in Motor Drive, the brains, Focusing Screens Other capabilities and the eyes of Canon; Full specifications with details illustrations of its various controls, available in HTML / PDF (184K) format.

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Instruction manuals for 300TL Flash & Canon T90
Canon A & T series SLR Models

Lenses: FL | Canon FDn lenses. | Early versions of FD lenses

| Message Board | for your Canon T90 SLR camera
| Message Board | for your Canon optics in a shared environment
| Message Board | Specifically for Dispose for Looking or Canon Photographic equipment

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Maintenance Team: Credit: Pawel Nabe for his image on the Data Memory Back. EEwyn Foo, my nephew, who has spent quite a number of nights converting the original manual in HTML format. Mr. Richard Yeow, General Manager -Optical Division of Canon Marketing for granting special permission to reproduce this manual into HTML format in his site as a form of obligation to all the T90 users worldwide. Maintainders of the T90 Message Board: Kaipin, Terry Carraway & Dr Strangelove; Tom Scott, for his images of the SPD cell, Chris Tutti for his initial effort to scan and prepared the T90 manual in PDF format. My staffs Miss Wati and Mirza for helping the basic setup work. * Canon, T90, FD Lenses, Canon Marketing are registered trade names or trademarks of Canon Inc. Japan.