Canon EOS 70D’s new autofocus technology targets video performance


Despite being relatively old for a consumer dSLR, the 2-year-old Canon EOS 60D remains surprisingly popular — as of this writing, the body currently ranks as the second best-selling dSLR on Amazon. It helps that the price dropped from $1,099 to as low as $599 over its tour of duty. So how do you follow up on that kind of popularity when you’re trying to fill its shoes at that initially high manufacturer price? Canon’s choice for its replacement, the EOS 70D, is to reinvent the autofocus system while bringing the rest of the camera up-to-date on current Canon standards.


Canon’s new autofocus system, dubbed Dual Pixel CMOS AF (DPA), is definitely a new take on autofocus technology. Typically, a single photodiode — the element on a sensor that collects light and converts it to an electrical signal that carries the image information — only passes on image data. DPA splits each photodiode in two, comparing the signals from each half using aphase-detection algorithm for autofocus, in addition to using the signal from the entire photodiode for image data. In contrast, Canon’s Hybrid AF system, used by the T4i,T5i, SL1, and EOS M simply supplements its phase-detection AF with contrast AF.

There are a few theoretical advantages of the new architecture. First, it has the potential to be faster, mostly because it drives the lens directly to the focus position; it doesn’t have to iterate to fine-tune position like contrast AF does, and can more quickly determine focus because it’s measuring off the sensor rather than having to go through a separate phase-detection sensor cycle. Second, it covers about 80 percent of the frame (like the SL1’s implementation), which improves off-center focus performance. And third, the lens shouldn’t need to hunt, which makes operations like rack focus smoother when shooting video.

It sounds like a pretty elegant solution to me, especially since it works with lots of existing Canon lenses — the company claims 103 — rather than requiring the stepper-motor (STM) lenses as with the hybrid CMOS-centric models. (I’m not an engineer, though, so I may be missing something important.) Canon does say you’ll get better video performance from the STM lenses, in part because they’re designed to be quieter.

Even if you’re a manual-focus fan, there are some nice updates in the 70D. It ramps up the continuous-shooting performance to 7fps, like the higher-end 7D, and gains the video codecs and controls of the 6D, plus the nice touch-screen interface for Live View and video recording. In keeping with Canon tradition, though, it’s incapable of outputting clean HDMI for recording to an external drive. (But because it’s an EOS, instead of a Rebel, I’m sure a Magic Lantern hack will be able to take care of that eventually.) It also gains Wi-Fi for wireless control and file transfer, even if it’s Canon’s typical lackluster implementation.

While there’s no radical changes to the design, there are enough tweaks to streamline the camera’s operation; most of them come from other cameras in the line, including the better combo Live View/movie switch and record button, and an easier-to-use lock switch for the multicontroller.

Here are the current models in that $1,200-or-so price segment. (Note: I’ll update the chart when the 70D’s full specifications magically appear):

Canon EOS 60D Canon EOS 70D Canon EOS 7D Nikon D7100 Pentax K-5 II/IIs
Sensor effective resolution 18MP CMOS
14 bits
18MP hybrid CMOS
14 bits
14 bits
14 bits
22.3mm x 14.9mm 22.5 x 15mm 22.3mm x 14.9mm 23.5mm x 15.6mm 23.7 x 15.7mm
Focal-length multiplier 1.6x 1.6x 1.6x 1.5x 1.5x
Sensitivity range ISO 100 – ISO 6400/12800 (exp) ISO 100 – ISO 12800/25600 (exp) ISO 100 – ISO 6400 ISO 100 – ISO 6400/ 25600 (exp) ISO 80 (exp)/
100 – ISO 12800/
51200 (exp)
Burst shooting 5.3fps
16 raw/58 JPEG
25 raw/130 JPEG
(7fps in 1.3x crop mode)
8 raw/30 JPEG
Viewfinder (mag/ effective mag) 96% coverage
n/a 100% coverage
100% coverage
0.92x/ 0.61x
Autofocus 9-pt AF all cross-type; center cross to f2.8 Dual Pixel CMOS
19-pt phase-detection AF all cross-type; center cross to f2.8
19-pt phase-detection AF all cross-type; center cross to f2.8 51-pt phase- detection AF
15 cross- type; center to f8 or faster
(Multi-CAM 3500DX)
11-pt phase-detection AF
9 cross- type
AF sensitivity 0 to 20 EV n/a -0.5 to 18 EV -2 to 19 EV -3 – 18 EV
Shutter speed 1/8,000 to 30 secs; bulb; 1/250 sec x-sync n/a 1/8,000 to 30 secs; bulb; 1/250 x-sync 1/8,000 to 30 secs; bulb; 1/250 sec x-sync 1/8,000 to 30 secs; bulb; 1/180 sec x-sync
Shutter durability 100,000 cycles n/a 150,000 cycles 150,000 cycles 100,000 cycles
Metering 63-zone iFCL 63-zone iFCL 63-zone iFCL 2,016-pixel 3D color matrix metering II 77 segment
Metering sensitivity 0 to 20 EV n/a 1 to 20 EV 0 to 20 EV 0 to 22 EV
Video H.264 QuickTime MOV 1080/30p/ 25p/24p; 720/ 60p/50p H.264 QuickTime MOV 1080/30p/ 25p/24p; 720/ 60p/50p H.264 QuickTime MOV 1080/30p/ 25p/24p; 720/60p/ 50p 1080/60i/ 50i/30p/ 25p/24p; 720/60p/ 50p H.264 QuickTime MOV
(60i/50i only in 1.3x crop mode)
1080/25p; 720/30p/ 25p Motion JPEG AVI
Audio Mono; mic input Stereo; mic input Mono; mic input Stereo; mic input; headphone jack Mono; mic input
Manual aperture and shutter in video Yes Yes Yes Shutter only n/a
Maximum best- quality recording time 4GB
(approx. 12 minutes)
n/a 4GB/29:59 min 4GB/29:59 min 4GB/25 min
IS Optical Optical Optical Optical Sensor shift
LCD size 3 inches articulated
1.04 megapixels
3 inches inches articulated touch screen
3 inches fixed
920,000 dots
3.2 inches fixed
1,228,800 dots
3 inches fixed
921,000 dots
Memory slots 1 x SDXC 1 x SDXC 1 x CF (UDMA 7) 2 x SDXC 1 x SDXC/ SDHC
(SDXC requires firmware upgrade)
Wireless connection None Wi-Fi None None None
Wireless flash Yes n/a Yes Yes Yes
Battery life (CIPA rating) 1100 shots
(320 Live View)
n/a 800 shots
(220 Live View)
950 shots
740 shots
Size (WHD, inches) 5.7 x 4.1 x 3.1 n/a 5.8 x 4.4 x 2.9 5.3 x 4.2 x 3.0 5.2 x 3.8 x 2.9
Body operating weight (ounces) 27 n/a 35 27.3 26.1 (est)
Mfr. price $899.99 (body only) $1,119.00 (body only) $1,599.00 (body only) $1,199.95 (body only) $1,095.95/
$1,199.95 (body only)
$999.99 (est, with 18-135mm lens) $1,349.00 (with 18-55mm STM lens) n/a $1,599.95 (with 18-105mm lens) $1,249.95 (with 18-55mm WR lens)/n/a
n/a $1,549.00 (with 18-135mm STM lens) n/a n/a $1449.95/ n/a (with 18-135mm WR lens)


Spec-wise, it really looks like it’ll give the D7100 some solid competition, though I wish the 70D had dual card slots and I don’t yet know how they compare when it comes to weather sealing and build quality. I do know I like the feel of the D7100’s body textures better than the 70D’s. And while the Pentax K II/IIs might be comparable for still-shooting, I don’t think its video will be able to match, if only because Canon’s codec offers the option of relatively minimal compression. While I don’t have official viewfinder specifications for the 70D, I do know it’s not 100 percent coverage, which is another disapppointment.

Given the 70D’s specifications, which pretty much match or outdo those of the 7D, either that camera is due for a replacement or discontinuation soon — most likely replacement, since I can’t see Canon not offering a more durable model with a better viewfinder.

And if none of this sounds that exciting to you, now may be the best time to pick up a 60D; at $599, it’s a great value and has better build quality than the Rebels.