The following is a set of ISO samples from the Canon EOS 70D, first with ISO 100, and then samples from ISO 800-6400 in the "still usable range", as well as a bonus of ISO 12800. Thanks once again to Broadway Camera for providing a tester unit.
The samples are unprocessed out-of-camera JPEGs shot with a retail version of the 70D using the lower-tier 18-55mm STM f/3.5-5.6 kit lens. The shooting parameters were:
- 35mm focal length
- +1 EV bias, evaluative metering
- Auto white balance
One caveat; these samples were rattled off in quick succession without the benefit of mirror-lock up. The ISO shot is the worst off because it uses the longest exposure time. Mirror-slap becomes less of an issue as the exposure times go down, but they all suffer from it to some degree, so judging the loss of edge acuity as ISO rises is a bit of a challenge. (It's something of a running gag on this blog that test shots end up being botched in one way or another...) Two crops are taken from each series to show the texture of the noise in a a shadow area (the black watch face) and a patch with strong reds (the de-focused Sony box in the background).
Note: Click on each image to view at 100%.
In terms of still image quality, I don't think much has changed since the pre-production samples were released. On a subjective basis, the camera does seem to be more dialed in than the pre-release images suggested, but there isn't much of an improvement to sway your initial opinions. In terms of still image quality, the 70D is more than adequate... competent even... but it doesn't move the game forward much. Compared to the 60D, you don't really notice a resolving power benefit with the the extra megapixels, but the texture is less pronounced throughout the ISO range and the colour saturation seems better preserved as you increase the ISO. Compared to the Nikon D7100, it lacks the extra bite that the double whammy of extra resolution + lack of AA filter gives, but you might not always be able to take advantage of the extra resolution.
In terms of practical usability, once again and as with every APS-C camera that I've used, I find that ISO 3200 is about as far as I would want to take it for care-free shooting; higher than that and images require more thoughtfulness during the shooting process and more time in post-processing. However, not all camera's are equal at ISO 3200; the D7000 is cleaner but has overall resolution. The D7100 has more resolution, but also more texture. This is why you can't measure image noise on a purely numerical basis; there is a subjective quality to it that has to be judged according to personal taste.
However, I do like this camera, of which I will describe in more detail in a follow-up post, but I don't like it because of its image quality. In the pixel-peeping digital age, that might sound like a harsh judgment, but it's not. But then again, outright still image quality wasn't the headline feature that Canon was trumpeting, was it...?