Canon 7D camera_First Impressions

If you’re a Canon user or looking to purchase your first DSLR then the Canon 7D should definitely be considered. This new camera is a direct competitor to the Nikon D-300, albeit with newer technology and features. Up until the release of the Canon 7D their was nothing in the Canon range to compare with the Nikon D-300.

CMOS Sensor

The 18 Megapixels APS-C sensor captures an amazing amount of information for a sensor of this size. The sensor produces an effective field of view of 1.6x the focal length. In other words a 100mm lens provides the same magnification as a 160mm (that’s 60% stronger) lens on a 35mm film-based or full frame sensor digital camera would. This 60% increase in effective focal length, with a corresponding loss in field of view, is common to most Canon DSLR cameras. Only the 5D and 1Ds models feature full frame sensors, which is the main reason they cost more. With most Nikon cameras the so called ‘Magnification Factor’ or ‘Cropping Factor’ is 1.5x or 50% that of a 35mm film-based or full frame sensor digital camera. Nikon’s full frame cameras include the D3, D3x and the D700.

Chip and Burst Capabilities


Dual DIGIC 4 chips provide fast processing speeds, ideal for the camera’s large file size and the up to 8 frames per second burst capabilities.

Buffer – 6 gun shooters beware!

The camera’s buffer can manage 94 JPEG or 15 RAW files in a single burst. That means you can photograph heaps of images, on continuous shooting mode, in a continuous burst. The buffer holds images until the camera is reader to process them. The more images you shoot in a single, continuous burst the more your camera’s buffer will fill. When the camera’s buffer is completely full, it may take a few seconds for the camera to right images to the card before there’s enough space in the buffer to allow you to continue shooting. As new cameras inevitably produce larger files the consequence is that larger buffers are also required.

Apparently you get up to 126 JPEGs per burst with the Canon 7D when employing a UDMA CompactFlash card.

Shutter

Rated to 150,000 cycles the camera’s shutter is the same design as that used in Canon’s 1D professional series

Exposure Compensation

The exposure that the camera determines is correct is referred to as Meter As Read (MAR). It’s often accurate, but not always. What’s more experienced RAW shooters often prefer to move away from MAR as the most desirable exposure.

The good news is that you don’t have to accept the exposure the camera judges to be right. You can employ manual exposure and set the camera to let either more or less light in than it deems appropriate. Alternatively, you can use some of the auto modes (e.g. AV or TV) to dial in an exposure compensation of + or –. Previous Canon digital cameras provided a +/- exposure compensation of just 2 stops. The new Canon 7D has expanded this to 5 stops above and below Meter as Read (MAR). I think this is an excellent improvement.

Sensitivity

ISO determines the sensitivity of the sensor to light. The higher the ISO the more sensitive the sensor and, as a consequence, the less light is required to make an exposure.

Setting a higher ISO will allow the camera to shoot at a higher shutter speed than it otherwise would under the same conditions (lighting, aperture). High ISO’s are often required to achieve faster shutter speeds, thereby reducing either subject or camera movement, under low light conditions. Alternatively high shutter speeds are an aid to freezing subject movement in action (sports, wildlife, surveillance) photography.

The 7D has an ISO range from 100 to 6400 and can be expanded up to 12,800, albeit it with a loss of image quality. At the higher ISO’s you can expect images that are flat (lacking contrast) and exhibit noise, particularly in shadows and areas of smooth tonality (skin, blue sky). It’s fine to shoot at high ISO’s where you may make images that wouldn’t have been possible with older technologies. Just be aware that there can be a quality compromise. So, just because you can doesn’t mean you should. If its bright and sunny try to shoot at the camera’s default ISO. With a Canon that’s ISO 100. Increase the ISO when and if required (capturing fast moving action, or shooting under low light conditions) and don’t forget to change it back to the default (or thereabouts) when you’re done.

Glenn Guy