Modern Classic SLR Series
Canon A-1 - Camera Operation
- Part VII

 

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Stopped-down AE Photography

There are basically two cases which require stopped-down AE photography. It is necessary when you use an FL lens. It is also necessary when any accessory without a full aperture signal pin is inserted between an FD or FL lens and the camera body to obtain higher magnifications in photomacrography or photomicrography. Such accessories include a bellows, extension tubes, a macrophoto coupler and the photomicro hood. It is also possible, but not necessary, to use the stopped-down AE mode when an FD lens is mounted directly onto the camera with no accessory in-between. In the stopped-down AE mode, exposure metering will be done not at full aperture as usual but, rather, at the same aperture that the picture will actually be taken.

To set the camera in the stopped-down AE mode when using an
FL lens, simply fold and push in the A-1's stop-down lever.

A set.jpg StopDWN.jpg
When using an FD lens, first advance the film and then disengage the lens aperture ring from the "A" mark before you push in the stop-down lever.

If the film is not advanced before turning the aperture ring from the "A" mark, the lens will stop down only as far as the aperture set for the previous exposure. It is impossible to push in the stop-down lever when an FD lens is set at "A".

When in the stopped-down AE mode, it does not matter whether the mode selectoris set to Tv or Av position. The camera will behave as if it was in the aperture priority AE mode. You must select the aperture by turning the lens aperture ring while the camera will automatically select a shutter speed. When you preview the exposure, only the shutter speed data will be displayed in the viewfinder. Unless the shutter speed data is flashing on and off, simply press the shutter button for an accurately exposed image. Exposure warnings are exactly like those in aperture priority AE. Set the aperture ring to a larger aperture if a shutter speed of the slow range flashes on and off in the viewfinder. The shutter speed value that flashes to indicate underexposure depends on the ASA film speed. Set it to a smaller aperture if the highest shutter speed of "1000" flashes on and off. When the shutter speed flashes on and off even when the aperture ring is turned to the extreme limits, you are outside the meter coupling range. Change the light level or switch to a more appropriate film.

Since you can determine correct exposure simply by watching the shutter speed data in the viewfinder, you need not keep an eye on the lens aperture ring as you turn it. However, for good depth of field when using accessories for close-up photography, it is best to close the lens to a relatively small aperture. More details are given in the instruction booklets for the various accessories involved.

You will find that your A-1 is unusually effective in photomacrography and photomicrography. Even though the amount of light reaching the film plane is greatly reduced due to attached accessories, the A-1 is capable of metering as low a light level as EV-2 (with ASA 100 film) in the stoppeddown AE mode. Furthermore, since the A-1 employs a through-the-lens meter, no exposure correction is necessary when accessories are inserted between camera and lens.

When you are finished operating in the stopped-down AE mode, unfold and press down on the stop down lever. It will pop out and the camera will be reset for full aperture metering. With an FD lens, you can now return the lens aperture ring to the "A" mark if you wish to use the A-1 in a full
aperture metering AE mode.

Note*: If you return the aperture ring to "A" but leave the stop-down lever pushed in, the camera will remain in the stopped-down AE mode and all subsequent exposures will be made at the lens minimum aperture. Though exposure will be correct, this situation severely strains camera mechanisms and is not recommended.

Note**: When performing stopped-down metering, you also have the advantage of being able to confirm depth of field directly in the viewfinder.

Note***: It is not possible to shoot sequentially with the Power Winder A or Motor Drive MA when in the stopped-down AE mode using an FD lens. In this situation, only single frame power winding is possible.

Warnings of Incorrect Operation in Stopped-down Photography

stpdwnlever.jpg
Two problems can arise ff you use the camera incorrectly in the stopped-down mode. The first problem occurs ff the stop-down lever of the camera is locked in before you mount the lens. If you expose a frame in this situation, it will be incorrectly exposed due to incorrect coupling of the aperture ring. To prevent this, before you mount a lens, make sure there is no red dot beside the stop-down coupling lever inside the camera body. The red dot is very conspicuous and appears only when the stopdown lever is pushed in.

stpdwnlever3.jpg
The second problem arises if you push in the camera's stop-down lever and, before taking a shot, release the stop-down lever and return the lens aperture rinz to the "A" mark. If you then try to press the shutter button, you will notice that neither it nor the film advance lever will operate. What's more, this is when the "EEEE EE" mark will flash in the viewfinder whether the viewfinder display switch is turned off or not.This appears to be a distressing situation, but it is very easily corrected.

Push the film advance lever into its retracted position close to the camera body. The multiple exposure lever is underneath. Push it to the left. Now turn the film advance lever. With this operation, the camera will work in the normal way.

Manual Override

You may have occasion to wish to cancel the A-1's AE capabilities to control exposure, both aperture and shutter speed, by yourself. This will be the case if vou are using a separate exposure meter, if vou wish to correct exposure in unusual lighting cond ons or in flash photography, or ifyou want to control exposure for creative effects.

manual1.jpg
With the A-1, this is a simple process. Using an FD lens, first disengage the aperture ring from the "A" mark. Set the AE mode selector to Tv. The Av setting is useless. Set the aperture by turning the lens aperture ring, and set the shutter speed by turning the AT dial. When you press the exposure preview switch or the shutter button halfway to preview the exposure, the data displaved in the viewfinder will be the same as if the camera was in shutter-speed priority AE.

You will see the shutter speed you have set on the AT dial. The aperture displayed is that that the camera would select on Auto. Although the aperture you have manually set on the aperture ring is not displayed, it is at that aperture that your picture will be exposed when you press the shutter button. You will also see the red "M" inside the viewfinder to indicate that you are in the manual mode.

Lens1.jpg  Lens2.jpg
To operate the camera manually using an FL lens or any other lens without a full aperture signal pin, set the AE mode selector to Tv. With these lenses you must always set the aperture by turning the lens aperture ring.

In the case of these lenses, the digital readout is unreliable, and it is better to cut it out altogether by switching off the viewfinder display lever. You must rely on your own experience for setting the exposure.

With an FD lens, if you set the AE selector to Av instead of Tv while the lens is away from the "A" mark, the digital readout win show the aperture you have set on the AT dial plus the corresponding camera-selected shutter speed as in aperture priority AE along with "M" for manual aperture setting. Although you are no longer in manual override, it is possible to make an exposure correction by setting the lens aperture ring to a different aperture than that on the AT dial. Exhosure will be made at the aberture set on the lens aperture rin~ and the cameraselected shutter sbeed

Self-Timer

SelfTimer1.jpg
The self-timer is usually used either so that you can include yourself in a picture or as an alternative to a cable release for the softest possible shutter release in delicate photography, such as photomacrography and photomicrography, or on other occasions when long exposures are necessary. This particular self-timer allows a time-lag of either two or ten seconds.

SelfTimer2.jpg
To use the self-timer, first make sure the film is wound and that the shutter speed is not at "B". If the film is not wound, the self-timer will act, but the shutter will not. The self-timer will not function normally at "B". Now set the main switch to 2 or 10.

Focus and compose your picture. You may press the exposure ureview switch to check the exposure. However, remember that since the A-1 is designed to reflect any last-second changes in exposure when in an AE mode, it will not set the exposure until a split second before the shutter itself is actually released.

Once you have completed these preparations, flick the eyepiece shutter lever to close the eyepiece shutter so that no light comes through the eyepiece to affect the exposure. Now press the shutter button and run into place if your purpose is to include yourself in the picture. The shutter will be released automatically following the time interval you have set.

The moment you press the shutter button the self-timer lamp starts to flash at the rate of two flashes per second. At two seconds before shutter release, it starts to flash eight times per second to warn you of impending shutter release.

If you wish to cancel the self-timer before shutter release, either switch the main switch to the "L" position or press the battery check button. You may repeat the self-timer process as many times as you wish. After completing self-timer photography, return the main switch to either "A" or "L".

Shutter.jpg
Please note: The eyepiece shutter should be closed wh never exposure is to be determined when your eve is not to the eyepiece. This is applicable to self-timer photography; remote control photography and often to tripod photography and is especially important in night photography.

Exposure Compensation Operations

expcompen1.jpg
You can, of course, make exposure corrections by operating the camera manually, but the A-l is also equipped with other devices which allow you to correct the exposure while in an AE mode.

Unusual lighting conditions which necessitate exposure correction include those instances when light takes up the major part of the viewing area, such as in beach or snow scenes and contre-jour or backlit situations in light is shining behind the subject, such as when your subject is in front of a window or when a lamp or the sun is shining behind him/her.

expcompen2.jpg
In such situations, the camera might be fooled into giving a reading which would underexpose your subject, so you must give it more exposure than the camera shows in AE.


This also applies to high-key or intentionally overexposed shots. On the other hand, it is necessary to reduce the exposure for a low-key shot. Some correction may also be necessary if your subject is not located in the central part of the viewing screen.

Exposure Compensation Dial

One device for correcting exposure in the AE mode is the exposure compensation dial. To make the correction, simply hold in the exposure compensation lock button while turning the outer knurled edge of the ASA setting dial until the compensation dial index is aligned with the desired correction. The exposure compensation scale covers a full +2 f/stop range in indications of 1/4 (underexposure by 2 f/stops), 1/2 (underexposure by one f/stop), 1 (normal AE exposure), 2 (overexposure by one l/stop) and 4 (overexposure by two f/stops). The scale is engraved in 1/3 f/stop increments so that intermediate settings may be used.

Since the digital readout is in only 1/2 flstop increments, depending on the situation the readout will not necessarily change to indicate an exposure adjustment of only 1/3 f/stop, but your picture will be exposed in the 1/3 f/stop increment you set on the dial.

Generally, exposure should be corrected whenever the high-key (light) area occupies more than half of the total viewing area. How much more or less exposure should be given depends on the lighting condition as roughly described below. However, these are only general guidelines meant to help you while experimenting.

Some situations require special measures. For instance, when shooting a subject against the sun or some other exceptionally strong light source, requiring drastic exposure correction, or when you shoot a subject in an unuarying lighting condition such as under photolamps in a studio, it may be better to use the exposure memory switch as explained on the next page.

Note: The exposure compensation dial can also be used to correct exposure in multiple-exposures.

Usable Range of Exposure Compensation
Dial According to ASA Rating
ASA6: 1/4..1/2..1
ASA12: 1/4..1/2..1..2
ASA25-3200: 1/4..1/2..1..2..4
ASA6400: 1/2..1..2..4
ASA12800: 1..2..4

Once you have made an exposure correction on a specific frame using the exposure compensation dial, do not forget to reset the dial to its original setting. Otherwise, all following frames will be incorrectly exposed.
Scale Exposure Correction Application
1/4 2 f/stops underexposure Black background
1/2 1 f/stop underexposure Spot lighting, black background
1 Normal  
2 1 f/stop overexposure Subject by a window, blue sky or sea backgrounds
4 2 f/stops overexposure Contre-jour portrait, white background, snow scene or blue sky background

Exposure Memory Switch

The A-1 also offers an exposure memory switch (Also commonly referred as "Auto Exposure Lock" or "AE-L" in short) for correcting the exposure in the AE mode. Essentially, this switch assures correct exposure by exposing the picture for your subJect no matter what the surroundings are.

AE Lock.jpg
When you press in the exposure memory switch, it locks the exposure value (EV) for whatever you are metering.

You can then compose the picture as you wish, and it will come out correctly exposed for whatever you metered. An extra advantage in this is that, depending upon whether you are in the shutter-speed priority or aperture priority AE mode, you can change either one and the camera will automatically select the other -to arrive at the same locked-in exposure value.

For instance, suppose you want to take a portrait of a subject against the sun. First move in closer to your subject until it is centered in about one-third of the total viewing area. Push and hold in the exposure memory switch to lock the exposure value metered for your subject. Now step back and compose the picture as you like. Change the aperture or shutter speed, depending upon which priority you are in, if necessary. Continuing to hold in the exposure memory switch.

Press the shutter button. Your subject will be correctly exposed. Of course, you have a problem if you cannot approach your subject to meter it directly. Then try to find an approachable subject which you think would give the same exposure value as your subject. Meter it, push in and hold the exposure memory switch.


Compose your subject and shoot for correct exposure.
Note: You must hold in the exposure memory switch until after you press the shutter button. It does not lock.

Changing the ASA Setting

There is another way to correct exposure which can be used whether you are in the manual or the AE mode. That is to change the ASA film speed setting on the camera. A film with an ASA rating twice that of another film requires only half the amount of light for correct exposure as compared with the other film.

For instance, if you have an ASA 200 film loaded, you can make an exposure correction equal to closing the aperture one f/stop or raising the shutter speed one step by changing the ASA setting on the camera to ASA 400.

Canon A-1 has one of the broadest ASA film speed in any manual focus camera with its ASA 6 to an amazing top scale of ASA 12,800 ! The ASA film speed scale provides another useful tricks by changing the ASA setting to compensate exposure. You may be stuck, for instance, indoors without flash. Even with ASA 400 film loaded in your camera, you may be forced to use undesirably slow shutter speeds. You may solve this by 'pushing" the ASA setting on the camera to a higher value. Usually this is done by multiplying the normal ASA rating by some multiple of two, say by two or four. In this case, the whole roll of film must be shot at the "pushed" ASA or you will have to sacrifice one or the other of a whole series of frames. Also, do not forget to inform your developing lab of the change in the film speed setting (In most cases, such request requires small amount of extra money to be charged) or the whole film will be incorrectly developed.

Warning: Not all films can be "pushed" and not all developing labs will handle them - especially the One-Hour color lab.
Reminder: This technique should not be confused with the above which involves intentional exposure correction for only one frame after which the ASA dial should be reset to its original value.

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