Canon T70

Canon’s T series of cameras were Canon’s first attempts at computerised cameras. They took these as far as they could with existing design concepts. The cameras are computerised but the lenses and lens mount were not. To go further along this line, Canon could have adopted the route taken by Pentax and Nikon and added electrical contacts and auto-focus drive to the existing FD mount. What they in fact did do was very courageous and in 1987 they abandoned the FD mount and introduced the EF mount. This EF mount had no mechanical couplings – all communication between the camera and lens was electronic. However, this was still three years in the future and this T70 uses entirely mechanical linkages between camera and lens.

• lens: n/a
• focal length: n/a
• apertures: n/a
• focus range: n/a
• lens fitting: FD bayonet mount
• shutter: Electronic metal focal plane
• speeds: 2 seconds to 1/1000 seconds plus B
• flash: hot shoe with Canon dedicated electrodes
• film size: 35 mm

Controlwise, this camera has done away with all the standard SLR controls. There is no film advance lever – film advance is via a built-in motor drive. There is no shutter speed dial – if you use Tv mode (shutter priority automatic exposure) you change the shutter speed by buttons. No film speed dial – the film speed is set by buttons and there is no DX system although Kodak had introduced DX cassettes the year before this camera was introduced. No film rewind crank – film rewind is motorised.

So, a description of what is there. The camera is fairly large – it measures 148 by 90 by 50 mm and weighs 580g including the batteries. Starting at the right hand end of the top plate, which is made from moulded black plastic, there is the shutter release button. This is black plastic and sits flush in a slightly raised plastic surround. The button is not threaded for any cable release – a horribly old-fashioned idea by 1984. Behind this button is the mark for the position of the film plane.

Between the shutter release button and the pentaprism hump is an LCD screen. This measures 22 by 15 mm. This contains a variety of information depending on the exposure mode you have selected. While the camera is switched off, this display continues to display the fact that a film is loaded and the number of frames used. When the camera is switched on, additional informations displayed. This is the exposure mode selected and, when the shutter release button is partially depressed, the shutter speed. For some reason, the aperture is not displayed.

In front of this display are two buttons marked down and up. most of the time, these do nothing but in conjunction with other buttons (more later) they are used to change settings. When the exposure mode is set to Tv (Time value, which means shutter priority exposure) these buttons alter the shutter speed.

In the middle of the top plate is the pentaprism hump. On top is the accessory shoe. This is an ISO hot shoe with a central contact and should work with any ISO standard flash gun. There are also a couple of extra contacts which are for controlling Canon’s own flash guns. On the back of the pentaprism hump is the viewfinder eyepiece. This is rectangular and measures 15 by 9 mm. Inside the viewfinder is the focus screen. In the middle of this screen are three concentric circles. Outside of these circles, the screen is matte ground glass. The outer circle signifies the area of the image used for partial AE metering.. The middle circle is a ring or micro-prisms which act as a focusing aid. Inside the these micro-prisms is a split-image disc.

On the right of the focus screen are a number of information LEDs. At the top is a green P to indicate that a the camera is in Program mode. This P flashes when when the selected shutter speed is too slow to reliably avoid camera shake. At the bottom is a red number which is the selected aperture when the lens aperture ring is set to ‘A’ – if the lens aperture ring is set to an actual aperture value, the red number is the suggested aperture as is the case when the exposure mode is set to Tv. You are not obliged to use the suggested aperture value. There are other options here for when you are not using FD lenses. Just as the aperture value is not displayed on the LCD screen on the top of the camera, the shutter speed is not displayed in the viewfinder.

Left of the pentaprism hump are three more buttons and a sliding switch. The rear button is a batter check button and is marked BC. This only works while the camera is switched on (as do the other buttons). Pressing this blanks the LCD screen and up to three bars are displayed at the bottom of the LCD screen. Three bars means battery power is good, two bars means battery power is low but still usable, one bar or no bars means that the batteries are exhausted and need replacing.

The middle button of the three sets the film speed. 1984 is recent enough that the film speeds are in ISO rather than ASA and this button is marked accordingly. While holding this button down, you need to press one of the two buttons marked down or up over on the right of the camera. Film speeds available range from 25 ISO to 1600 ISO and can be altered in 1/3 stop increments.

The front button of the the three is marked MODE and is used, again in conjunction with the down and up buttons, to switch between the three Program modes and shutter priority (Tv) mode. Here might be a good place to talk a bit about the five modes available.

First, program mode. This controls both shutter and aperture to get the ‘best’ exposure – the lens’ aperture ring must be set to ‘A’. The next mode is Program Tele which is much the same as Program but will choose the fastest possible shutter speed commiserate with a good exposure. Program Wide selects the smallest lens aperture commiserate with a good exposure , thus ensuring a good depth of field.

The next mode is Tv or Time value. This allows you to set your preferred shutter speed. This has two sub-modes. If the lens aperture ring is set to ‘A’, you get shutter priority automatic exposure. Alternatively, you can directly set the aperture – full manual mode and an M appears both on the LCD screen and in the viewfinder.

If you are using an old FL mount lens (they will fit just fine) or if you are using close-up rings or bellows, there is a fifth mode which is stop-down automatic exposure mode.This mode is aperture priority automatic exposure. You set the lens aperture, which will close down giving you a dim viewfinder image. When you press the shutter release button, the camera will select a suitable shutter speed. In this case, the camera will not display the shutter speed but the camera will display either HL (1/125, 1/180, 1/250, or 1/350) or HH (1/500, 1/750 or 1/1000). This last mode will not work if an FD mount lens is used.

On the left of the three buttons is a sliding switch. This has four positions: Off, Average, Partial (AE L) and Self Timer. Off is self-explanatory – in this position, the electronics are switched off and nothing works. The next position of Average is how this camera is intended to work. Average refers to the metering of the light – the meter works out the average illumination over the whole image with emphasis the centre.

Then third position is Partial where metering only occurs in the marked circle in the viewfinder. In this mode, partially depressing the shutter button will lock the exposure and allow you to meter a critical portion of the image and then recompose. The fourth position of this slider is the self-timer. This gives a ten second delay between pressing the shutter buttonand the shutter firing. The camera beeps during this delay and the beeping is faster during the last two seconds.

This is all the controls on the top plate – now for the front of the camera.

As always, the main thing on the front of the camera is the lens mount. This is the Canon FD mount (Have no idea as to what FD stands for, if anything). I am using my older breech-lock lenses on this camera and they fit and work vey well. Breech-lock lenses attach by fitting the lens to the mount and turning a ring on the lens to fasten. Newer FD lenses fit by turning the whole lens. This mount is entirely mechanical and has no electrical contacts at all. The flange distance is 42 mm (the distance between the surface of the lens mount and the film). On the camera side of the mount, there are two mechanical sensors and two mechanical actuating levers. Looking air the camera, there is a button just inside the mount at about five o’clock. This is pressed in when attaching a lens It would seem to tell the camera that a lens is attached but it might be to allow the camera to distinguish between FD and the older FL lenses which used the same three pronged bayonet.

On the other side of the mount, at around eight o’clock, is a hole with a recessed button in it. This allows the camera to sense when the lens’ aperture ring is set to “A” (automatic). This recessed button is missing from the FD mount on my older Canon AT-1. Right at the bottom of the mount, just inside the mounting ring, is a lever which moves to the left when the shutter release button is pressed. This closes the the lens’ aperture to its set value just prior to the shutter opening. The second actuating lever is at about two o’clock. This lever sets the aperture when the lens’ aperture ring is set to “A”. Because of the way that Canon chose to fit lenses to this camera, the mounting surfaces of the camera touch but do not move past each other so no lens release button is required.

To the left of the lens mount, near the top of the body, is a combination switch and button. The button is an automatic exposure lock button. Pressing this while in Partial (AE L) mode allows you to fix the exposure with the critical portion of the image in the centre of the focus screen by pressing and holding this button and then reimposing the image artistically. The same thing can be achieved by partialy pressing the shutter release button.

The switch is a ring around the exposure preview button. The purpose of this switch is to lock the shutter speed. This is required because in situations where the displayed shutter speed is too slow for safe hand holding, the camera will increase the shutter speed from the displayed value. Turning this switch to “L” prevents this from happening.

On the bottom left of the body (while looking at the front of the camera) there is a socket for an electric cables release. The only thing left to mention on the front of the camera is the presence of strap lugs on each top corner.

The base of the camera has a tripod socket. This is an ISO socket with 1/4 inch UNC thread. This socket is in line with the lens. Also on the base is the hinged cover to the battery compartment. This compartment holds two AA batteries which are both readily available and cheap. The only other thing on the base is the film rewind button. This film rewind button is motorised so the is a sliding release as well as the rewind button – this is to prevent accidental rewinding of the film before it is complete. To rewind the film, you slide the release and then press the button. It is not necessary to hold the button in once the film has started rewinding. The film will be would completely into the cassette. The camera needs to be switched on for the rewind to work but switching the camera off will not stop rewinding once it has started. If you want to stop rewinding before all the film is in the cassette, you can stop rewinding by pressing the BC (Battery Check) button. If you do this as soon as the the number 1 disappears from the frame counter, you will be left with the film leader still outside the cassette (which I prefer).

Inside, the camera is fairly normal. To open the back, there is a catch on the left hand edge of the camera. There is a button to press while sliding the catch down – this is to prevent accidental opening of the back with film inside. The back is sturdy moulded plastic with good flanges to make the joint light tight – no manky foam seals to replace!

The cassette chamber is on the left. This contains a printed code – Y10-09 in the case of my camera – I suspect that this is a date code for the camera’s manufacture.

The shutter is in the centre as usual. This is a vertically travelling metal bladed shutter. The shutter is an electromagnetic shutter, according to the manual. This is entirely dependent on battery power. Many cameras of this time have a default shutter speed that will work mechanically if the batteries run out, but not here.

This camera automatically loads film. The new film goes in the chamber on the left, you pull the film leader across the film gate until it reaches the large orange mark on the right. You then close the camera and turn the power on. The camera will pull four frames across and latch them onto the take-up spool. Four frames is more than I would use if manually loading a camera – I would usually waste two frames only. So, this camera will give me a couple of frames less per roll of film but will still give the required number of frames for each roll – I just like the extra ‘free’ frames.

In use:

I have no light seals to replace, so the camera is loaded with Kodak Gold Ultra 400 ISO colour film. This is about 15 years past its use-by date so I might get a colour cast but I find this is rather rare. In any case, I am more interested in the mechanical behaviour of the camera and its metering capability.

What I am finding, which is annoying if nothing more, is that the shutter release button needs a very firm press. For an electronic button, this is surprising – I would expect a light touch to be sufficient. There is also a noticeable delay between pressing the shutter button and the shutter firing – about a second, which does not sound long but is much more than is comfortable. I have had a comment from a long-term user who states that his camera never had a noticeable delay between pressing the shutter and the shutter firing. I wouldn’t really expect there to be on such a camera but mine is old, 35 years old, and this age will explain much.

I have had the test film back from Ag-Photo. Looking at the negatives, they all seem to be well exposed – the image density is around what I would want. Also, the shutter is working smoothly and film advance is regular. Downside – this is entirely due to me using very old film. I regularly use film beyond its best-before date with no problems – as much as 40 years past with Black and White film – but 15 years for colour film is asking for problems and I have some. So, there is no colour cast (a frequent problem with old colour films) but there is much grain, far more than is comfortable. I also have very high contrast, the shadow areas lacking much detail. I cannot blame the camera for this.

The images: