Canon T70

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The T70.

Top, showing controls.

The Canon T70 was a 35mm FD-mount single-lens reflex camera introduced in April 1984 as the second in Canon's T series. The T70 started with the concepts explored in 1983's T50, took them further, and applied them to a more sophisticated camera. While the Program AE-only T50 was intended as a beginner's camera, the T70 gave the photographer a lot more control over the camera's operation while keeping the T-series philosophy of simplicity in control and operation intact.

1 Power features
2 Controls
3 Metering
4 Exposure modes
5 Data back
6 References

[edit] Power features

All film transport on the T70 was powered—loading, advance and rewind. The continuous shooting rate, at 0.7 frames per second, was slow, but the motor drive was faster than most people could manually wind. To load the camera, the photographer simply had to pull the film leader out to an orange mark and close the back—the camera did the rest, loading the leader onto the spool and advancing to the first frame automatically. All powered camera functions drew on two AA batteries in the grip. A built-in lithium battery (BR-1225 or CR-1220) was used for memory backup; these lasted about five years and had to be replaced by a technician, since replacing it required partial dismantling of the camera body.

[edit] Controls

The T70 used a LCD mounted on the top of the right-hand side of the camera as a major component of its user interface. Two buttons above the display labelled 'UP' and 'DOWN' adjusted the selected parameter and the results were shown on the LCD. Buttons on the right-hand top of the camera selected the parameter to be modified.

[edit] Metering

Switch to select metering mode.

The T70 included two different metering methods; both used a silicon photocell above the viewfinder eyepiece. Center-weighted average metering was the standard metering method, averaging over the whole frame with a slight preference towards the center of the frame, where the main subject is most likely to be. With strongly backlit scenes, or ones where the subject is spotlit against a dark background, center-weighted averaging produces underexposure or overexposure, respectively. For such situations, the T70 also supported selective area metering, which metered only the center 11% of the frame. The metering mode was selected by a sliding switch on the top left-hand side of the camera (from the photographer's perspective). This switch also selected self-timer mode and had a Lock position.

[edit] Exposure modes

The T70 supported eight different exposure modes. These were:

Program AE (autoexposure). In this standard mode, the camera judges the shutter speed and aperture for average photographic scenes.
Wide Program AE. Here, the camera is biased towards choosing narrow apertures for greater depth of field, most often useful with wide-angle lenses.
Tele Program AE. Here, the camera is biased towards choosing wider apertures for narrow depth of field and fast shutter speeds, most useful with telephoto lenses.
Shutter-priority AE. Here, the user selects the shutter speed and the camera chooses the correct aperture.
Programmed flash AE. This is designed to work with the Speedlite 277T dedicated flash unit.
Electronic flash AE. For flash exposures with non-dedicated flash units.
Manual. Here, the photographer chooses both aperture and shutter speed.
Stopped-down AE. For use with older FL-mount lenses that do not support open-aperture metering. Also for use with macro photography attachments such as extension tubes and bellows, and for using non-Canon lenses with an adaptor. Cannot be selected with a FD lens attached.

[edit] Data back

A dedicated Command Back 70 supported date and data imprinting as well as time exposures, to take a photograph at a programmed time, and to take time-lapse photos at programmed intervals. The shutter of the T70 was not battery dependant during bulb exposures, and was one reason why the command back could support timed exposures of several hours duration.

[edit] References

Canon Inc. Canon T70. From Canon's online Camera Museum.
Photography in Malaysia (2000). Canon T70 Camera. Retrieved on October 20, 2005.
Canon Inc. (1984). Canon T70 User Manual. Retrieved from the Canon FD Documentation Project on October 20, 2005.
Canon Inc. (1984). Canon T70 Service Manual. Retrieved from the Canon FD Documentation Project on October 20, 2005.

Mount Type	Series	Model
Canon SLR cameras
FL		FX (1964), FP (1964), Pellix (1965), FT QL (1966), Pellix QL (1966), TL (1968)
FD		FTb (1971), EF (1973), TLb (1974), TX (1975)
	F	F-1(1971), F-1n (1976), New F-1 (1982)
	A	AV-1 (1979), AT-1 (1978), A-1 (1978), AL-1 (1982), AE-1 (1976), AE-1 Program (1981)
	T	T50 (1983), T60 (1990), T70 (1984), T80 (1985), T90 (1986)
EOS	1	EOS-1 (1989), EOS-1N (1994), EOS-1N RS (1995), EOS-1V (2001),
		EOS 650 (1987), EOS 620 (1987), EOS 750QD (1988), EOS 850QD (1988), EOS 630QD (1989), EOS RT (1989), EOS 700QD (1989), EOS 10sQD (1990), EOS 1000F (1990), EOS 100 (1991), EOS EF-M (1991), EOS 5/5QD/A2/A2e (1992), EOS 1000FN (1992), EOS 500 (1993), EOS 888 (1993), EOS 50 (1995), EOS 500N (1996), EOS 3 (1998), EOS 88 (1999), EOS 300 (1999), EOS 30 (2000), EOS 3000N (2002), EOS 300V (2002), EOS 3000V (2003), EOS 30V (2004), EOS 300X (2004)
		Canon DSLR cameras
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