Canon EOS 70D review
22.5x15mm 20.0-megapixel sensor, N/A zoom (N/A equivalent), 755g
The Canon EOS 70D is the company's latest enthusiast-oriented SLR. It replaces the Canon 60D, and has various enhancements that distinguish it from the likes of the Canon EOS 700D. The viewfinder is significantly larger, there are lots of single-function buttons, a passive LCD screen on the top plate and a command dial and rear wheel for direct access to exposure settings. It's faster than both the 700D and the 60D, with a 7fps continuous mode that lasted for 108 JPEGs or 16 RAW frames before slowing to the speed of the card.
Price, specs and rating based on the body-only package
When originally writing this review, the 70D cost £999 for the body only, but as is always the case with digital cameras prices have dropped significantly in the last six months . You can now pick up a 70D for around £850 from the likes of Jessops, Park Cameras and WEX photographic. That means the gap between the 70D and full-frame EOS 6D has extended to more than £500, while the Nikon D610 is even pricier so both are out of the running if you're looking to keep your budget below £1,000. Panasonic's GH3 costs £750 body-only, so if you're looking to shoot video it may be the better choice even after you've bought a few lenses.
The 20-megapixel resolution is Canon's highest to date for an APS-C sensor, and the sensor design is radically different to anything we've seen before. Each pixel not only measures the intensity of light, but also the direction, with each one made up of two photodiodes facing left and right. This helps the sensor to perform phase-detect autofocus, determining not just whether the image is in focus, but also, if not, by how much. It means the lens can jump straight into focus rather than shuttle back and forth in search of a sharp picture.
Phase-detect autofocus is already available in all modern SLRs when using their viewfinders, but in most cases it's disabled in live view mode. The 70D's ability to perform phase-detect autofocus directly on the sensor makes it much faster than the 60D to focus in live view mode.
We've seen this technique a few times before, most recently on the EOS 700D. However, previous implementations have been limited to a few dedicated phase-detect points dotted across the sensor. What's special about the 70D is that almost every pixel can contribute to phase-detect autofocus. The active area is quoted as 80 per cent of the frame, horizontally and vertically – you can't place the autofocus point right at the edge of the frame.
Testing with the 18-135mm STM lens, the benefit was immediately obvious. It took around half a second to focus and capture a photo in live view mode, rising to around one second in low light. That's twice as fast as the 700D, and about five times faster than the 60D.
It's a superb result, but we can't help wondering if it could have been even faster. It typically took less than 0.2 seconds from when we pressed the shutter button to hearing a double-beep to confirm that focus was achieved, but then it took another 0.3 seconds for the shutter mechanism to kick in. Half-pressing to focus and then fully pressing to capture removed this shutter lag, though. We measured 2.1 seconds between shots in live view mode, which is much slower than the 0.4 seconds it achieved when using the viewfinder. It delivered 7fps continuous shooting in live view mode, but focus was fixed and the screen was blank during bursts.
Still, the bottom line is that live view mode is far more useful than on any other Canon (or Nikon or Pentax) SLR. It helps that the screen is articulated, with a side-mounted hinge that allows it to tilt up, down, to the side and right around for self-portraits – a feature that's conspicuously absent from the Nikon D7100 and Canon and Nikon's full-frame SLRs.
The 70D's screen is touch-sensitive too, so moving the autofocus point in live view mode couldn't be easier. Subject tracking is available but we weren't bowled over by its reliability. The touchscreen also speeds up navigation of the Q menu, which gives quick access to a wider array of functions than are covered by the dedicated buttons. The touchscreen provides an alternative way to navigate the main menu, but we found it quicker to use the command dial and rear wheel to jump to a particular setting.
The 70D is fastest when using the viewfinder, so it's good to see some improvements here too. The 60D's 9-point autofocus sensor has been ditched in favour of the 19-point sensor first seen in the EOS 7D. All 19 points are cross-type for increased sensitivity, and they were fast and accurate even in extremely low light. There's a new button next to the command dial for expanding the active area. The largest area encompasses all 19 points, and when used in conjunction with the AI Servo autofocus mode, allows for some basic subject tracking. It can't match the sophistication of the 3D Tracking mode in the Nikon D7100, though.
IT'S ALL 'APPENING NOW
Wi-Fi is built in, with the same functions that we saw on the Canon EOS 6D. They include remote control via the accompanying iPhone and Android apps, with access to exposure settings and the ability to move the autofocus point using the smartphone or tablet's touchscreen. While the 6D had to make do with lethargic live view autofocus, the 70D was much more responsive when shooting remotely. The app can also access the camera's card to view full-screen previews with EXIF metadata, apply star ratings and instigate transfers.
We appreciate how both the remote shooting and image browsing modes are accessible without locking up the camera's controls. Photos appeared in the app within two seconds of being captured, letting us use an iPad to review shots in more detail that the camera's 3in screen allows. However, previews and transfers are limited to 2.5 megapixels, so it's not so useful for checking focus. Enabling Wi-Fi disables the USB port and video capture, so a tablet can't be used as a remote video monitor.
The iOS app worked fine in our tests but we could only connect our Nexus 4 smartphone via an existing network rather than make a direct connection. We've heard others have made direct connections with different handsets, but if this is an essential feature to you it might be worth popping along to a retailer and testing it with your own device.
FOCUS ON VIDEO
The new autofocus technology is great news for photographers, but it's potentially even more exciting for videographers. The 70D's video autofocus was the most responsive we've ever seen from a large-sensor camera, adjusting in less than a second when we moved the autofocus point using the touchscreen. There was no sign of focus hunting, and face detection and subject tracking helped us follow moving subjects – although once again, it was a little unreliable.
Even so, when we tapped on a subject to focus on, more often than not, focus would remain locked as it moved nearer or further. We've always maintained that manual focus is the only way to achieve polished results, but for the first time, here's a video autofocus system that we can envisage being used in professional productions. With a choice of 24, 25 or 30fps capture at 1080p, clips up to 30 minutes and an All-Intra mode that encodes at 75Mbit/s to avoid compression artefacts, it all looks pretty promising for serious video production.
It's a shame, then, that details in the 70D's videos aren't a little sharper. Its footage looked decent enough in isolation, but the Panasonic GX7 and Panasonic GH3 were able to resolve fine details with greater fidelity. We also noticed a tendency for moiré interference on repeating textures such as fabric and bricks. The full-frame Canon 5D Mark III showed big improvements in video detail compared to previous EOS cameras, but it seems that these advances haven't been built into the 70D. We achieved better results by selecting the Neutral Picture Style and sharpening up the footage in software, but this didn't get rid of the moiré interference.
It will bother some more than others, but the Panasonic GH3 (left) has a clear advantage over the 70D (second from left) for details in videos. The 70D's details can be improved by rolling off the sharpness and contrast and then sharpening in software, but it still can't quite match the GH3 - click to enlarge
Another hurdle for serious video production is the lack of a headphone socket, which limits the usefulness of the microphone input. The HDMI output can stream a live feed but it's not a clean feed to send to an external recorder. Despite the 70D's superb autofocus performance, the Panasonic GH3 remains our top choice for video production. The 70D isn't too far behind, though. For more casual users who still demand high quality, its more responsive video autofocus may tip the balance in its favour.