Canon EOS 70D review

The Canon EOS 70D delivers the smoothest Live View focus we've seen in a traditional D-SLR, but it can struggle to lock that focus in dim light.
Photo of Canon EOS 70D

The Canon EOS 70D ($1,199 direct, body only) is the first traditional D-SLR we’ve seen with an on-chip phase detect autofocus system that doesn’t have to hand off to contrast detection in order to confirm focus. That gives it the ability to deliver quick, smooth autofocus when recording video, but there’s still some room for improvement in dim lighting. The 20-megapixel camera is a solid option for Canon shooters looking to move up from a Rebel body, but don’t want to go full-frame. Despite its video prowess, it doesn’t manage to oust our Editors’ Choice for midrange D-SLRs, the Nikon D7100. The Nikon may not focus as quickly in Live View mode as the Canon, but we liked it slightly better overall.

Design and Features
The 70D is a bit bigger than the next camera down in the Canon’s APS-C SLR lineup, the Rebel T5i. The 70D measures 4.1 by 5.5 by 3.1 inches and weighs 1.7 pounds, compared with the 3.9-by-5.2-by-3.1-inch, 1.1-pound T5i. Extra physical controls and a larger, heavier pentaprism viewfinder help account for the added girth and heft. The pentaprism viewfinder is a step up in quality than the pentamirror that you’ll find in a camera like the T5i. It’s a solid piece of glass that, along with the reflex mirror, directs light captured by the lens to your eye. It doesn’t quite provide full-frame coverage; Canon claims that it shows you 98 percent of what the lens is capturing, cutting off some information at the edges. The Nikon D7100 and the Pentax K-5 II do better; they both deliver 100 percent of the frame to your eye.

As you would expect from a serious D-SLR, there are plenty of controls squeezed into the 70D’s body. There’s a depth of field preview button on the front, at the edge of the lens mount. On the top plate you’ll find a mode dial to the left of the eyepiece; it’s locking, so you’ll need to depress the center button in order to turn it. The power switch is directly below that dial. There’s a monochrome information LCD to the right of the finder, and ahead of that you’ll find buttons to adjust the autofocus mode, drive mode, ISO, and metering pattern. There’s a control in front of that, a small button that allows you to adjust the active focus points, and the shutter.

The rear of the camera is a bit more basic with Menu and Info buttons, as well as a toggle switch to change between still and video capture with an integrated button to toggle Live View. In the top rear right corner, just behind the information display, you’ll find an AF-ON button that activates focus (by default, a half-press of the shutter does the same, but some shooters prefer to disable that and dedicate a control to the task), an exposure lock button, and a button that lets you select from any of the camera’s 19 focus points. The latter will only function if you’ve got the focus set to manually select a point. The 70D doesn’t offer as many focus points as the D7100—it has 51 to choose from—but all of the 70D’s points are the more precise cross-type; the D7100 only has 15 cross-type points, and they’re all bunched in the center of the frame.

You also get a rear control dial with a center set button; in most modes, the dial grants direct access to exposure compenstation adjustment. The Q button, a common feature on Canon SLRs, activates a touch-sensitive menu on the rear LCD. It provides quick control over the aperture, shutter speed, ISO, exposure compenstation, flash compensation, picture style, white balance, focus mode, metering pattern, drive mode, image quality, and over a few different image optimization settings. Many of these duplicate on-camera controls, but there is something to be said about seeing all of your control options in one place.

The rear LCD is a vari-angle design; it’s hinged so it can swing out to the side of the camera, and it can tilt so it can be viewed with the camera above your head, at your waist, or facing you. The 3-inch display packs an excellent 1,040k-dot resolution, and is touch sensitive. The Sony Alpha 77 also features a hinged display, but it’s not a touch screen, and the hinge mechanism is a bit different. It’s viewable from all of the same angles, but it rises up above the viewfinder in order to twist and face forward.

Like the full-frame 6D, the 70D integrates Wi-Fi (but there’s no GPS like you’ll find in the 6D and Sony Alpha 77). The implementation is similar to other Canon cameras: You can transfer photos to your smartphone or tablet via the free EOS Remote app, beam them to another Canon camera, print to a Canon Wi-Fi printer, view on an HDTV via DLNA, or upload directly to the Web. The latter requires you to connect the camera to your computer and configure the Web services that you’d like to use via the Canon Image Gateway service.  The EOS Remote app also supports remote control. A Live View feed appears on the screen of your phone or tablet, and you’ll be able to set the focus point, adjust exposure compensation and fire the shutter; but that’s it, there’s no full manual control available. Canon has disabled video recording when Wi-Fi is enabled, so you’ll need to disable Wi-Fi from the menu when you want to utilize the video recording function.

Performance, Focus, and Video
The 70D starts and shoots in about 0.5-second, records a shutter lag that’s close to zero in good light, and can fire off shots at 7 frames per second. Continuous shooting is limited to 8 shots at that pace in Raw+JPG mode, with about 7 seconds required to fully write the images to a SanDisk 95MBps memory card. Switching to Raw only extends the capability to 17 shots, and JPG shooters will be able to fire away for 125 images before the rate starts to slow.

To compare, the Nikon D7100 is a little faster to start and shoot (0.2-second), and its shutter lag also clocks in at less than 0.1-second. Its burst rate is slower, for Raw or Raw+JPG shooting it only hits 5fps, and is limited to above 5 images at that rate; switching to JPG improves the speed to 6fps, but only for 22 shots. There is a 1.3x crop mode in the D7100, a feature that the 70D doesn’t offer; this cuts down the resolution of images, but delivers edge-to-edge autofocus capability and improves the capture rate to 7fps for JPG, with 100 shots available before slowing. The 70D shoots a bit faster and for a lot longer at full resolution, giving it an edge in terms of capturing action.

When using the optical finder, focus is extremely quick. The 70D can lock and fire in less than 0.1-second in good light, though that figure drops to about 1.5 seconds in very dim conditions. The D7100 locks on in just as short of a time in good light, and manages to focus in dim light in about 0.9-second.

Live View focus speed is where the 70D sets itself apart from other D-SLRs. On-sensor phase detect pixels are speedier than typical contrast detect systems. In good light the 70D can focus in about 0.4-second when set to Live View. Compare this with the 1.7 seconds that the D7100 required. Dim light is a challenge; I couldn’t get the 70D to lock and fire in our standard low light test with an f/4 lens attached, there just wasn’t enough light hitting the sensor. Switching to the Canon EF 50mm f/1.2L USM alleviated the issue—focus was confirmed in 1.3 seconds. You’re going to want to use fast glass if you want to autofocus properly in dim light. With the D7100, the contrast AF system worked, albeit slowly, with a narrow-aperture lens in similarly dim conditions; it just took 2.5 seconds to do so. The Sony Alpha 77, which is a full-time Live View SLR that uses a dedicated phase detect sensor, had no problems locking focus in dim light, even with a modest 18-55mm lens attached; it did so in about 1.5 seconds. The Alpha 77 lacks an optical viewfinder (it has an excellent EVF and a rear LCD), but some shooters aren’t willing to use anything but an optical viewfinder.

Live View is also used for video, and the quick, smooth focus system is a winner under most conditions. Lenses that bear an STM designation offer smooth, silent focus; automatic changes in focus are timed on the slower side, simulating the effect of slowly pulling focus as you would see in a Hollywood film. When you use a lens with a USM motor, like the 50mm f/1.2L, the change in focus is just as slow, which helps to hide the stuttering, jumpy focus effect that I’ve seen in previous Canon D-SLRs like the T5i. That’s not there with the 70D; racking from one point of focus to another with the 50m f/1.2L is smooth.

The actual quality of the video is impressive. The 70D records HD footage at 1080p30, 1080p24, or 720p60 quality in QuickTime format. You can choose from All-I or IPB compression for any format. The footage is crisp and sharp, and depending on the lens you attach you can eke impressively shallow depth of field from the camera. There is some evidence of the rolling shutter effect when panning—this causes the bottom part of the frame to advance more quickly than the top. There’s an internal mic and I was happy with its audio quality for casual recording, but if you’re doing serious video work, you’ll want to want to hook up an external mic. There’s a standard 3.5mm connector for that, and levels can be adjusted via the menu, but there’s no headphone jack so you won’t be able to monitor audio in the field.  Despite having a mini HDMI port, the 70D doesn’t support uncompressed output over HDMI; you’ll need to move up to a higher-end camera if you want to use it in conjunction with a field recorder.

Image Quality and Conclusions
Many are looking at the 70D for its video capabilities, but at its heart, its main purpose is still photography. I used Imatest to check its performance. The camera ships as a body only, but I did look at the sharpness of the new EF-S 55-250mm f/4-5.6 STM lens when paired with the body; you can see those results in that review. But one item of note in relation to sharpness is that while other manufacturers are releasing enthusiasts D-SLRs that lack an optical low-pass filter (the Nikon D7100 and Pentax K-5 IIs are notable examples), Canon has stuck to its guns and covered the 70D’s 20-megapixel sensor with an OLPF. This saps a bit of critical sharpness, but eliminates the possibility of color moiré—a rainbow effect of false color. Whether the trade-off is a worthwhile one is a matter of personal choice and your choice of photographic subjects; if you frequently shoot objects that are prone to show moiré (certain fabric patterns and feathers come to mind), you may prefer a camera with a filter. But those effects are easy enough to fix on a case-by-case basis with software, which has led photographers to opt for cameras that prioritize resolution over all else.

I used Imatest to gauge image noise, which can detract from detail and give photos a grainy look as the ISO is increased. The 70D keeps noise under 1.5 percent through ISO 800 when shooting JPGs at default settings. It doesn’t jump too high at ISO 1600 (1.7 percent) or at ISO 3200 (1.8 percent). Pixel-level examaination on a calibrated NEC MultiSync PA271W display shows a slight drop-off in detail from 800 to 3200, but it’s not drastic. At ISO 6400 some detail starts disappear, and at the top ISO of 12800 details are smudged away. You can eke more detail out of the sensor by shooting in Raw; at ISO 6400 the details are sharp and the tight grain pattern is not distracting. Pushing Raw images to ISO 12800 introduces some rougher grain, but there’s still an impressive amount of detail. The Pentax K-5 II delivers some of the best image quality that I’ve seen from an APS-C D-SLR at higher ISOs; it keeps noise under 1.5 percent through ISO 1600, and hits just 1.6 percent at ISO 3200. But like the 70D, its images start to suffer at ISO 6400.

In addition to the mini HDMI and microphone ports, the 70D features a mini USB and a remote control connector. There’s no PC Sync socket; you’ll need to move up to a higher-end body like the 7D for that. And there’s no headphone jack. You get a single SD card slot that also supports SDHC and SDXC cards. The 70D lags behind the D7100 and the upcoming Pentax K-3 in that regard; both cameras sport dual card slots. Like other cameras in this class, a vertical battery grip is available ($270).

The Canon EOS 70D’s most impressive feature is its video capability. Live View focus is the fastest I’ve seen in a traditional SLR, and transitions in video are slow and smooth, just as if you had a focus puller slowly turning the focus ring of your lens. But that focus can fail to lock on in very low light, which isn’t an issue with the Sony Alpha 77—an SLR with an EVF that focuses quickly whether you opt to use the rear LCD or eye-level finder. As a still camera, the 70D delivers a solid burst shooting rate, good JPG output at all but its top two ISO settings, and quick autofocus. It’s a solid step-up in terms of quality when compared with the T5i, but we still give preference to the Nikon D7100. The D7100 may not focus as quick in Live View mode, but we prefer that its image sensor omits the OLPF, and it offers slightly better overall performance.

Specifications
Dimensions 4.1 x 5.5 x 3.1 inches
Interface Ports mini USB, mini HDMI, Mic, Remote
Megapixels 20 MP
Battery Type Supported Lithium Ion
Recycle time 0.14 seconds
LCD dots 1040000
LCD size 3 inches
Touch Screen Yes
Media Format Secure Digital, Secure Digital High Capacity, Secure Digital Extended Capacity
Maximum ISO 12800
Type D-SLR
GPS No
Boot time 0.5 seconds
Sensor Type CMOS
Weight 1.7 lb
Lens Mount Canon EOS
Video Resolution 720p, 1080p
Waterproof Depth (Mfr. Rated) 0 feet
LCD Aspect Ratio 3
Image Stabilization None
Shutter Lag 0.05 seconds
Sensor Size APS-C (15 x 22.5mm) mm
Viewfinder Type Optical

Verdict
The Canon EOS 70D delivers the smoothest Live View focus we've seen in a traditional D-SLR, but it can struggle to lock that focus in dim light.
Published under license from Ziff Davis, Inc., New York, All rights reserved.
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