During
the early days of digital SLRs, Canon was pretty much the undisputed leader in
CMOS image sensor technology. Almost every new EOS model came with an increase
in resolution and high ISO range, and when the EOS 7D appeared in
late 2009, the company had progressed from 3MP to 18MP, and ISO 1600 to ISO
12800, in just over nine years. But since then Canon's APS-C cameras have all
sported variants on the same basic sensor design, to the extent that you could
be forgiven for wondering what on earth their engineers were doing all day. Now
we know.
The
EOS 70D is a mid-range SLR for enthusiast photographers that from the outside
looks like a sensible, indeed desirable upgrade to the EOS 60D. It borrows
many of the best bits from Canon's existing SLRs, including the autofocus
sensor from the EOS 7D, the fully articulated touchscreen from the EOS
700D (Rebel T5i), and built-in Wi-Fi from the EOS 6D. But on the
inside it sports an entirely new sensor that is, potentially, revolutionary. It
offers 20.2MP resolution, but uses a 'Dual Pixel CMOS AF' design in which every
single pixel is split into two separately-readable photodiodes, facing left and
right. This means that in principle they are all capable of phase detection
autofocus in live view and movie mode.
On-chip
phase detection is nothing new - we first saw it in the Fujifilm F300EXR back
in 2010. Since then it's been adopted in one form or another by most
manufacturers, with arguably its most successful implementation coming in
Nikon's 1 System mirrorless models. But because until now it's used
relatively few active pixels scattered sparsely across the sensor, it's had
practical limitations, often only covering a restricted area of the frame and
struggling once the light drops below outdoor daylight levels. Canon says that
its Dual Pixel AF system, in contrast, works across an area 80% of the frame
width and height, in light levels as low as 0 EV, and at apertures down to F11.
This means it could well be the most capable live view autofocus system we've
yet seen on any type of camera.
We'll
look at the technology behind the EOS 70D's live view AF in more detail later,
but let's not forget that it has to work as a conventional SLR too. To this end
it uses the same 19-point AF sensor as the EOS 7D for viewfinder
shooting, but with slightly simplified control options in firmware. It can
rattle shots off at 7fps for up to 65 frames in JPEG or 16 in Raw, and its
standard ISO range covers 100-12800, with ISO 25600 as an expanded option.
Image processing is via the DIGIC 5+ processor first seen in the EOS 5D
Mark III.
In
terms of control layout the EOS 70D is a logical evolution of the EOS 60D,
adopting many of Canon's intervening updates and improvements. So it offers a
full set of external controls to operate most key functions, and Canon's
well-designed Quick Control screen to cover pretty much everything else. It
also adopts the superb touchscreen interface that debuted on the EOS 650D (Rebel
T4i), which we've found to be more useful than you might at first think. The
70D also regains an array of features that disappeared between the EOS 50D and
60D, such as AF microadjustment.
Canon
EOS 70D key features
20.2MP
APS-C 'Dual Pixel CMOS AF' sensor
DIGIC
5+ image processor
ISO
100-12800 standard, 25600 expanded
7fps
continuous shooting, burst depth 65 JPEG / 16 Raw
'Silent'
shutter mode
1080p30
video recording, stereo sound via external mic
19-point
AF system, all points cross-type, sensitive to -0.5 EV
63-zone
iFCL metering system
98%
viewfinder coverage, 0.95x magnification, switchable gridlines and electronic
level display
Fully-articulated
touchscreen, 1040k dot 3" ClearView II LCD, 3:2 aspect ratio
Single
SD/SDHC/SDXC card slot
Built-in
Wi-Fi
Single-axis
electronic level
Built-in
flash works as off-camera remote flash controller
AF
microadjustment (can be set individually for up to 40 lenses, remembered by
lens serial number)
In-camera
High Dynamic Range and Multiple Exposure modes (JPEG-only)
'Creative
Filter' image processing styles, previewed in live view
