Live View is a feature of all current Canon EOS digital SLR (DSLR) cameras. The major feature of an SLR camera is the reflex mirror that allows the viewfinder to see exactly what the lens is seeing. In Live View, the mirror is lifted up out of the way and the shutter is opened, thus allowing light to pass through to the CMOS sensor where it can then be displayed live on the rear LCD display.
Whilst in Live View, the depth-of-field preview button, found on the front of EOS cameras next to the lens mount, can also be used. Combined with the magnification functions this can be used to gain a very clear idea of exactly what will be in focus in the image with your current focus and aperture settings.
The camera can also perform autofocus in Live View, using one of three modes. Quick Mode AF, will drop the reflex mirror and the normal AF sensors perform autofocus, Live Mode AF will perform a very accurate contrast-based autofocus using data from the CMOS sensor, and Live Mode Face Detect will search the scene for faces and then use the Live Mode focusing system to focus on them.
Live View is most useful when shooting static subjects as looking at the rear LCD panel at arm’s length and trying to take pictures is not recommended. Instead, the camera should ideally be placed on a tripod to allow the full benefits to be attained. This makes Live View perfectly suited to still life, landscape, architectural photography and EOS Movie shooting.
For many shooting situations, Live View is not necessarily a useful feature – the optical viewfinder gives a clear, bright view of the subject and allows you to focus accurately. However, in some situations, being able to see what the camera is seeing on a large LCD screen is beneficial.
When using Live View you can see not only what the sensor is seeing, but also you can make use of the exposure simulation feature to get an accurate view of exactly what the image will look like before you press the shutter button.
Live View can also be used to adjust fine focus, which is especially useful when shooting macro subjects. The Live View image can be zoomed in to 5x or 10x magnification – this provides a very detailed view of any part of the image and makes critical focus adjustments much easier.
By pressing the INFO button in Live View, the display can be cycled through image only, the image with basic information, image with full information and image with a live histogram. On cameras that feature a Dual Axis Electronic Level, this can also be overlaid on the Live View display