Using the Canon EOS 5 in Av mode with Evaluative metering. Using the Canon EOS 5, or any 35mm SLR cameras for the matter, in the Aperture-priority AE (Av) feature, is something I don't do very often since most of the time, I prefer to use Shutter-priority AE (Tv) with the balance between Program AE and Manual exposure modes. Nevertheless, using the EOS 5 in this semi-automatic mode that emphasizes depth-of-field rather than action-stopping images, is quite simple. Unlike the EOS -1 series models, the EOS 5, like other entry-level and mid-range EOS cameras, uses a Command Dial in conjunction with the Main Electronic Input Dial, to set the exposure. For Aperture-priority AE or any of the other exposure modes to be set, one only needs to turn the Command Dial to the Av index. The f-stops to be selected will be accomplished by the Main Electronic Input Dial and is limited by the amount of both the maximum and minimum apertures available in the lens mounted on the EOS 5. The camera's LCD panel will display the f-stop selected. Canon EOS 5 Command Dial set to Av mode index When is the best time to use the Av mode ? For starters, Canon's L-series EF lenses are designed to enable professional photographers to shoot at the maximum apertures and still retain top image quality without stopping down the f-stops. As such, setting the lens' maximum aperture opening while letting the camera take care of the correct shutter speed, is one example to use this automatic mode. Some professionals prefer to set the maximum aperture, like f/2.8 or f/4, and have their EOS cameras take care of the shutter speeds to ensure they get the desired effect. They may want to maintain a constant depth-of-field or simply opt for an out-of-focus background for their pictures, which in this case, is better accomplished via the Av mode rather than Tv. For example, the EF 75-300mm f/4.5-56 IS USM zoom lens has a maximum aperture of f/5.6 at its 300mm setting. LRT tracks Telekom Tower against KL Tower/cityscapes Rather than using Tv, the Av mode of the EOS 5 allowed me to set f/5.6 and let the camera choose the appropriate shutter speed to get the correct exposure of the LRT tracks (above, left) while utilizing the IS feature (which was shot at 1/30 sec, ISO 100). Next, part of the Telekom Tower was framed against the distant KL Tower and cityscapes in the background, with the aperture set at f/8 and the shutter speed set by the EOS 5 was 1/350 sec. << Back to Main . 1 . 2 . 3 .