The DSLR Difference

The A2's focal length (in 35mm equivalent) ranges from 28mm to 200mm. This is a 7X range which suits most types of photography with very little weight. With two accessory lenses, the A2 can have 22mm or 300mm focal lengths. This is of great convenience and many photographers are delighted by this possibility.

For the part of DSLRs, a much wider range of focal length can chosen from. Single lenses even exist with 7X to 10X zoom to match the convenience of the A2. However, these lenses come with the price of reduced image quality and slower apertures. Lenses with large zoom ranges usually have slow maximum apertures such as F3.5-F6.3, which at the telephoto end, is much slower than the A2's F3.5 at 200mm (300mm with accessory lens). This is important when considering the need for high ISO settings. A similar shutter speed at F3.5 with ISO 200 and at F6.3 with ISO 800 would produce the same exposure. Therefore, a DSLR with a single lens can't easily match the range, aperture speed and convenience of a non-SLR camera. Conversely a DSLR with a set of interchangeable lenses can have flexibility way beyond that of the a fixed lens camera. Note that the price of fast quality lenses for SLR cameras is very high and must be considered when evaluating its value.

There is a component that can't be matched between these two types of cameras: depth-of-field. At a given 35mm equivalent focal length, the A2 has depth-of-field that is more than 7 times deeper than the 20D. This ratio is much bigger when the focus distance approaches the hyper-focal distance of the lens. A photographer can interpret this as good or bad. Increased depth-of-field obviously allows much more sharpness and is less prone to focus errors. This is particularly apparent in macro shots. Reduced depth-of-field allows for selective focusing and increases isolation between the foreground and the background of a picture. Only the photographer can decide if this is an advantage or disadvantage.

It is known that DSLRs produce better pictures. What matters though is the suitability of those pictures. For many display purposes, differences can become indistinguishable. In order to evaluate picture quality, we viewed the images of both cameras at different sizes up to 25"x19" and compared sharpness, noise, contrast, color and saturation.

Sharpness appears about equal without counting noise (discussed later). Some pictures appeared to be sharper on the A2, others on the 20D. Below are two 100% crops of pictures from each camera. These represent a cropped region from an image 25" wide. At smaller sizes, there was no way to distinguish the sharpness of any images produced by these two cameras.

KM A2 - ISO 100, 1/250s F11
Canon 20D - ISO 100, 1/160s F11