Features
According to Canon’s Mike Owen, the 22.3×14.9mm (APS-C-sized) CMOS sensor inside the EOS 550D has a lot in common with the unit inside the EOS 7D, but they are not the same devices. The effective pixel count of 18 million, for example, is the same, and unusually for an entry-level DSLR, the micro lenses are also gapless. This is significant as more of the light that exits the mounted optic is directed onto the EOS 550D’s photoreceptors, and this helps to minimise the level of noise as the receptors’ signal needs less magnification.
However, a notable difference between the two cameras’ sensors is that the unit in the EOS 550D only has four read-out channels rather than eight. The smaller number of read-out channels, and the single, rather than dual, Digic 4 processor mean that the EOS 550D has a maximum continuous shooting speed of 3.7fps rather than the 8fps of the EOS 7D. Although a rate of 3.7fps is very respectable for an entry-level camera, keen sports photographers may look enviously at EOS 7D users shooting away at the faster rate – at least until they come to editing the inevitably larger number of images. Canon claims a maximum burst depth of 34 high-quality JPEG images or six raw files, but with a SanDisk Extreme III SDHC installed I was able to shoot 300 high-quality JPEGs or seven raw files in a single burst, so it’s worth investing in a faster card if you want to shoot long continuous sequences.
Although a compatible external flashgun, such as the Speedlite 580 EX II, can be controlled via the camera’s menu, the EOS 550D relies on such units (or the Canon ST-E2 Speedlite Transmitter) for providing wireless control over other flashguns. Unlike the EOS 7D, the EOS 550D doesn’t have wireless flash control built in. Another difference between the EOS 7D and the EOS 550D is that the EOS 550D accepts SD, SDHC and SDXC media rather than CF cards. Given that there are now 64GB SDXC cards available, this isn’t a major drawback and it enables the camera to be smaller. In addition, the EOS 550D is the first Canon DSLR to allow control over an Eye-Fi card via the camera menu. This type of feature is more likely to appeal to professionals working in a studio than to enthusiasts, but some may find a use for it.
The EOS 550D is also the first Canon DSLR to have an LCD screen that breaks the one-million-dot barrier. I will discuss this in more depth later, but the image on the 3in LCD screen is made up of 1,040,000 dots. The screen also has a 3:2 ratio, so more of it is dedicated to displaying images and there are no blacked-out areas. The screen displays 100% of the scene in Live View mode, and both contrast and phase-detection autofocus are possible (in addition to manual focus) when images are composed using this technology.
By and large the EOS 550D’s specification meets most of the requirements of the average enthusiast photographer. In addition to the slower continuous shooting rate, however, keen sports photographers who are trying to choose between the EOS 550D and the EOS 7D may be disappointed to learn that the EOS 550D has the same nine-point AF system as the EOS 500D, rather than the 19-point module of the EOS 7D. While this means that the speed of the continuous AF response cannot be tailored to suit the subject, this is unlikely to be a concern for those photographers for whom nine points are more than enough.
