Canon 70D Tech Info

Canon 70D Technical Info

by Mike Tomkins

Sensor. The story of the Canon EOS 70D begins and ends with its 20.2 megapixel, APS-C CMOS image sensor. It's absolutely unique, with two photodiodes sitting under a single shared microlens at each pixel location. This, as we've described in much more detail further up the page, allows Canon to provide for on-chip phase detection at every pixel location over almost two-thirds of the sensor's surface area.

The new sensor is also slightly higher-res than the 18.0 megapixel chip of the EOS 60D, although the difference is modest and accompanied by a reduction in pixel pitch from 4.3 to 4.1µm. Simultaneously, the sensor's active area has increased slightly to 22.5 x 15.0mm, bringing a minute reduction in the focal length crop from 1.61 to 1.6x.

Processor. The Canon 70D replaces its predecessor's DIGIC 4 image processor with a newer DIGIC 5+ variant, first seen in the EOS-1D X professional digital SLR. The new processor allows improvements both in performance, and in image quality.

Performance. In terms of performance, the Canon EOS 70D brings a 26% increase in our lab-measured burst-shooting speed, from the 5.3 frames per second of the 60D to a swift 6.7fps in the newer camera.

The performance (and increase in performance) don't quite match those claimed by Canon, but they're in the ballpark, and you'll certainly notice the extra speed.

Sensitivity. Equally important is the Canon 70D's noise performance. Here, the extra horsepower of DIGIC 5+ allows more sophisticated noise reduction algorithms, while the newer sensor design is said to mitigate effects of the reduced pixel pitch. Canon claims raw performance to be on par with the EOS 60D at like sensitivities, despite the slightly higher resolution, and our testing backed that up -- at the pixel level, both cameras turn in a very similar performance.

Thanks to these improvements, the Canon 70D sports an expanded default ISO sensitivity range of 100 to 12,800 equivalents, with the ability to push to ISO 25,600 if needed. By contrast, the 60D topped out at ISO 6,400 ordinarily, with an expansion to ISO 12,800 available. The difference is, it has to be said, much as you'd expect given the three additional years of development possible since the 60D's release.

Lens mount. As you'd expect in an enthusiast EOS-series camera, there's a Canon EF lens mount that's also compatible with EF-S lenses.

35mm lenses have a 1.6x focal length crop when mounted on the EOS 70D. Two kit lens choices are available; either the 18-55mm STM lens, or the 18-135mm STM lens. Alternatively, you can buy the body alone, and supply your own lenses.

Autofocus. This, more than anything else, was obviously a key target for improvement in the Canon 70D. We've already detailed the new on-chip autofocus system, dubbed Dual Pixel CMOS AF, so if you've skipped ahead, scroll up to our "Close Look at the Canon 70D's Dual Pixel CMOS AF" for in-depth info.

Briefly, though, Canon's new system allows it to provide for phase detection at every pixel location across 80% of the frame height, and 79.56% of its width, both for still image shooting in Live View mode, and more importantly, during video capture. The system is accurate enough that there is no need for a fine-tune with contrast detection autofocus after phase detection has completed. Since it covers so much of the frame, it also allows phase detection autofocusing at apertures where dedicated sensors no longer work. Its main drawback, other than the fact you can't use the optical viewfinder, is that it operates only on one axis, and so isn't sensitive to vertical detail.

You're only going to derive the benefit of that system for movies and Live View, however. In regular still-image shooting through the viewfinder, the Canon 70D reverts to a dedicated phase detection sensor. It's not a new chip, but it's new to this class, and borrowed from the Canon EOS 7D. It provides 19 autofocus points, each of them a cross-type, optimized to detect both horizontal and vertical features. In the center of the screen is an X-type sensor, designed to detect diagonal lines as well. It also requires lenses of f/2.8 or better, while the other points will work up to f/5.6.

The dedicated AF sensor has a working range of -0.5 to 18 EV (at 23°C/73°F, ISO 100).

Viewfinder. The Canon 70D features an eye-level pentaprism viewfinder with just over 97% coverage according to our lab testing, slightly improved from the 60D, which had a little over 96%. (The 50D had 95% coverage, so the figure is gradually creeping closer to the ideal, although Canon still lags some more affordable competitors in this area.)

The viewfinder magnification is unchanged from the 60D, at 0.95x (-1m^-1 diopters with 50mm lens at infinity). Also unchanged is the eyepoint: 22mm from the center of the eyepiece lens.

Just like the 60D, the Canon EOS 70D provides a diopter adjustment range of -3.0 to +1.0m^-1 diopters. However, it now lacks its predecessor's ability to exchange focusing screens, and instead features a fixed transmissive LCD screen.

Display. Just like its predecessor -- which introduced the feature to the EOS line -- the Canon 70D includes a tilt / swivel LCD display (or Vari-Angle, in Canon parlance). The tilt mechanism allows the LCD to be folded out 90 degrees to the left of the 70D's body, while the 270-degree swivel mechanism allows the screen to be turned 180 degrees to face upward or forward, or 90 degrees in the opposite direction to face directly downward. This also allows the LCD to be stowed facing inward, offering a modicum of protection against light bumps, scratches, and fingerprints.

The Canon 70D's screen comprises a three-inch, gapless Clear View II TFT LCD panel, in place of its predecessor's Clear View type. The change should translate to reduced glare and better contrast under strong ambient light. Dot count is still 1,040,000 dots, which roughly equates to a 720 x 480 pixel array. The Canon 70D's panel has 100% coverage and 170-degree viewing angles. Display brightness is adjustable in seven steps.

Touchscreen. Unlike the 60D, the Canon EOS 70D's display is overlaid with a touch-sensitive panel, allowing it to serve as a user interface element.

It's a capacitive panel like those found on most smartphones these days, and is particularly useful for touch autofocus during video capture, letting you seamlessly guide your viewers' attention from one subject to another with subtle focus changes.

Exposure. The Canon 70D offers a third fewer exposure modes on its Mode dial than did the 60D, a change that makes it rather simpler and more approachable. Modes that have been retained include the obvious Program, Aperture-priority, Shutter-priority, and Manual, plus Camera User, Creative Auto, and Flash Off. The Full Auto mode has been replaced by an Auto+ (aka Scene Intelligent Auto) mode, the Movie mode dropped altogether, and the five Scene modes that previously merited their own Mode dial positions have been combined into a single Scene position.

Metering. Like the 60D before it, the Canon EOS 70D includes a 63-zone iFCL metering sensor, which has a dual-layer design. Each layer is sensitive to different wavelengths of light, allowing subject color to be taken into account when determining exposure. Information on focusing points is also considered in metering calculations.

The Canon 70D's exposure metering options include 63-zone Evaluative, Center-weighted Average, Partial (7.7% of image frame at center), and Spot (3.0% of image frame at center). Metering sensitivity range is specified at 1 to 20 EV (at 23°C/73°F, with 50mm f/1.4 lens, ISO 100).

Shutter. Available shutter speeds from the electronically-controlled focal plane shutter in the Canon 70D range from 30 to 1/8,000 second in 1/2 or 1/3 EV increments. There's also a bulb mode of unstated maximum duration. Shutter life is rated by Canon at 100,000 cycles, unchanged from the EOS 60D.

Internal flash. Befitting its status as a non-pro camera, the Canon EOS 70D includes a built-in flash, something that consumers appreciate, and enthusiasts may find benefit from occasionally, as well. (It's nice not to have to carry an external strobe on every trip, just in case.)

The 70D's built-in, popup flash strobe has a guide number of 12 meters (~39.4 feet) at ISO 100. Coverage is approximately 27mm (35mm-equivalent), and X-sync is at 1/250 second.

External flash. As well as the built-in flash, there's an intelligent hot shoe compatible with EX-series Speedlites and Canon's E-TTL II metering system. Both Canon's IR and radio-controlled wireless flash systems are supported, with the appropriate hardware.

Level gauge. Canon has included a single-axis electronic level function in the EOS 70D, capable of indicating side-to-side roll. Unlike some competing cameras, there's no front-to-back pitch indication, however. That means you should be able to ensure level horizons, but you won't get any help with preventing converging verticals.

Sealing. Just like its predecessor, the Canon EOS 70D includes weather sealing. Canon describes the camera as dust and moisture resistant, and says that it is sealed to the same degree as was the EOS 60D.

Creative. As well as the various exposure modes mentioned previously, the Canon 70D includes quite a few multi-shot and effects shooting modes.

The HDR mode shoots three images with a range of +/- 3 stops, and then merges the trio in-camera to create a single image with greater dynamic range. Images can be microaligned for you before merging, if you're shooting handheld.

HDR Backlight control is similar, except that you cannot disable image microalignment, and that the algorithms are optimized to draw out shadow detail while retaining highlight detail.

Multiple Exposure mode overlays anywhere from 2 to 9 sequential images -- or you can use a raw file as a starting point -- to create a single cumulative image. Two methods of merging are possible. Additive mode is similar to what you'd get when exposing a frame of film twice. In Average mode, every pixel's value is simply the average of that pixel location in all of the source images.

In Handheld Night Scene mode, the 70D will capture four sequential exposures, raising sensitivity enough to attain a hand-holdable shutter speed. It will then merge all four in-camera, averaging out some of the noise across exposures. The result: a handheld picture with less noise than you might expect, so long as your subject is reasonably static.

Finally, there is a choice of seven different Creative Filter effects in the 70D. These include Grainy Black and White, Soft Focus, Fisheye Effect, Toy Camera Effect, Miniature Effect, Art Bold Effect and Water Painting Effect. Each offers three different effect strengths, and can be previewed before shooting your final image.

Video. The 70D doesn't just provide for still imaging. Video can be captured, too, at up to Full HD (1920 x 1080 pixel) resolution. When shooting at this maximum resolution, you have a choice of 30, 25, or 24 frames per second. At 720p HD (1280 x 720 pixels), your choices are 60 or 50 frames per second. Finally, there's a VGA (640 x 480 pixel) mode, recorded at 30 or 25 fps.

Full-time phase detection movie autofocus is possible, although you can opt for single AF or manual focusing, should you prefer.

You can choose to control exposure either fully automatically, or fully manually. If set to a Priority or Bulb mode, the EOS 70D will use Program autoexposure. It's also possible to use Auto+ exposure, which will be set whenever any Basic Zone mode is dialed in.

Exposure lock is available in Creative Zone modes, and you can also apply exposure compensation. ISO sensitivity ranges from 100 to 6400 equivalents in Basic Zone modes, and can be raised as high as 12,800 equivalent in Creative Zone modes.

All movies use H.264 / MPEG-4 AVC compression, but you have a choice of ALL-I or IPB compression with high-def movies. VGA movies always use IPB.

By default, audio is captured with a built-in stereo microphone. Both an external mic jack and manual audio levels control capability are also provided. There's also a wind filter function.

Connectivity. The Canon 70D features similar connectivity to the full-frame Canon 6D, including built-in Wi-Fi for remote shooting, sharing and transferring of photos with Canon's EOS Remote App. Note, though, that the Wi-Fi connectivity is not available in all markets. For some markets, a variant called the Canon EOS 70D (N) will be sold, and this will not include Wi-Fi.

this currently available only for iOS and Android devices. If you're using a smart device running BlackBerry's eponymously-named operating system, Nokia's now-largely-retired Symbian OS, or Microsoft's Windows Phone, Windows RT, or Windows 8 operating systems, you're out of luck.

There's also one important difference from the Canon 6D in the connectivity department. Unlike that camera, there is no GPS in the Canon 70D. Other connectivity features are standard fare, including both a USB 2.0 port and HDMI output (mini-HDMI, type C). There is also a 3.5mm microphone jack for attaching an external mic.

Storage. The 70D accommodates SD/SDHC/SDXC cards for storage, just like the 60D and 6D, and similarly features only a single card slot.

Power. The 70D employs a Canon LP-E6 rechargeable lithium ion battery for power. The battery is CIPA-rated for 920 shots on a single charge.

Accessories. A range of accessories are available for the Canon EOS 70D. If you shoot with the 60D, you'll be pleased to hear that quite a few -- including the LP-E6 battery packs, LC-E6 battery charger, ACK-E6 AC adapter kit, and CBC-E6 car battery charger kit -- can be used with your 70D. You can also keep your Angle Finder C, dioptric adjustment lenses, viewfinder eyepiece frames, remote switches, and cables.

There is one accessory you'll need to buy anew, though, and sadly it's one of the most expensive. The Canon EOS 70D uses a new portrait / battery grip, the BG-E14, priced at around US$270. The BG-E9 grip used with the 60D will not work with the newer camera.