Canon EOS 70D review – Noise, resolution and sensitivity
Images: Both images look good taken at ISO 5000, although there is some colour noise in the JPEG that was easily removed from the raw file
As is to be expected, when editing raw images more detail can be revealed than can be had from JPEGs, and there is plenty of latitude for sharpening. One thing to note is that, while it is possible to remove virtually all colour noise from raw images using the latest version of Adobe Lightroom, there is some slight colour noise visible in the shadow areas in JPEG images, even at ISO 400. While this isn’t much of an issue straight from the camera, if you plan to edit the shadows of JPEG images, they will have to be handled carefully.
Regarding detail resolution, JPEGs reach almost 30 at ISO 80-200. This is a good amount and is a reflection of the camera’s 20.2-million-pixel resolution. The degradation of resolution is actually quite slow, with the first real notable drop coming at ISO 3200, where JPEG images resolve to around 24-26 on our test chart. Although there are hints of colour noise beyond ISO 400, it really becomes a concern at ISO 6400. At this point luminance noise also becomes a lot stronger, really softening the image and reducing resolution. By the time the extended ISO 25,600 sensitivity is reached, JPEG images only resolve to around 16-18 on our test chart.
These images show 72ppi (100% on a computer screen) sections of images of a resolution chart, captured using the Sigma 105mm f/2.8 macro lens set to f/5.6 . 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 the images, the better the camera’s detail
resolution is at the specified sensitivity setting.