Angela Nicholson looks at the Canon EOS 7D and EOS 5D Mark II to see whether full frame still holds an advantage over APS-C-format cameras
Resolution, noise and sensitivity
Image: These images show 72ppi sections of images of a resolution chart. We show the section of the resolution chart where the camera starts to fail to reproduce the lines separately. The higher the number visible in these images, the better the camera’s detail resolution is at the specified sensitivity setting. Images are taken using the Sigma 105mm f/2.8 EX DG Macro lens
Our tests show that the EOS 5D Mark II and EOS 7D produce very similar levels of noise across the sensitivity range. However, despite the current climate of competition for high-sensitivity settings, Canon capped the EOS 7D at ISO 12,800. Perhaps any higher was a step too far with the APS-C-format sensor, or the company wanted to give the EOS 5D Mark II an advantage. Of course, it is possible that the company has changed its opinion of what is an acceptable level of noise.
Although the ISO 25,600 setting on the EOS 5D Mark II can produce some excellent results, the shadows often suffer from banding and this sensitivity needs to be used with caution. At ISO 12,800, the EOS 7D’s maximum sensitivity setting is 1EV lower, with obvious implications for the shutter speed, but the images are evenly textured and banding isn’t a problem.
Image: At ISO 6400 the EOS 7D raw image has slightly more chroma noise, but it is still impressive
Our resolution chart images show that the EOS 5D Mark II is capable of resolving a little more detail than the EOS 7D, but in photographic images it is more difficult to distinguish between the results from the two cameras than some might expect.
When comparing default-setting JPEG files with the same framing taken at ISO 200 with the EF 24-70mm f/2.8L USM lens wide open on each camera, the image from the EOS 5D Mark II is a little softer and less detailed than the shot from the EOS 7D. However, when the aperture is closed down the image becomes sharper and the details are much crisper.