Canon EOS 650D - Rebel T4i

The headline specifications - 18MP CMOS sensor, 9-point AF sensor, 3:2 flip-out 1.04m dot screen are all familiar from the 600D. But each of these has been significantly improved and it's the fine detail that makes the 650D interesting - both as a product in itself and in what it says about Canon's view of the future.

The traditional SLR design, with its roots in 35mm film photography, notably offering poor focusing performance in Live View and video, and ergonomics centered around eye-level shooting.

The EOS 650D appears to be designed to meet these challenges head on, with new features aimed at improving its live view and video performance. Firstly, it becomes Canon's first SLR capable of continuously tracking and maintaining focus on a moving subject while recording movies. This may not sound like a big deal - lots of cameras claim to be able to do so, with varying degree of success - but what matters is how it's implemented.

The EOS 650D has a new 'Hybrid CMOS' sensor that now includes pixels dedicated to phase detection autofocus (in a similar fashion to Nikon's 1 J1 and 1 V1 mirrorless cameras). The Hybrid AF system uses these to set the lens quickly to roughly the correct distance, then uses contrast detection AF to fine-tune focus. In principle, this should provide faster and more certain focusing for live view and video shooting compared to previous cameras that relied on CDAF alone. There are more details later in this preview.

Canon EOS 650D / Rebel T4i Key Features

• 18MP APS-C 'Hybrid CMOS' sensor
• Phase detection AF from imaging sensor for Live View and Video
• Continuous autofocus in movie mode with subject tracking
• 14-bit DIGIC 5 processor
• ISO 100-12800 standard, 25600 expanded
• 5 fps continuous shooting
• 9 point AF system, all sensors cross type, central sensor F2.8 (from 60D)
• 63 zone iFCL metering
• 1080p30 video recording, stereo sound with internal or external mics
• 1.04m dot 3:2 touch-sensitive vari-angle ClearView II LCD (capacitative type, multi-touch support)

Touchscreen control
The EOS 650D also becomes the first SLR to feature a touchscreen. This is of the capacitative rather than resistive type, meaning it's sensitive to contact rather than pressure, like most modern smartphones. In Live View and Movie modes the screen can be used to specify the point of focus and release the shutter, as we've seen before on several mirrorless cameras. It also supports multi-touch and gestures, meaning that it offers iPhone-like pinch-to-zoom and swiping from image to image in playback. The results is a user experience that smartphone users will immediately find familiar.

What's more, the entire interface can be controlled by touch in a completely seamless fashion, including the onscreen Q menu that's used to access secondary functions, and the entirety of the menu system. Fortunately this doesn't come at the cost of external controls, and the EOS 650D offers essentially the same level of button-and-dial operation as its predecessors; the screen simply adds an additional control option. You can turn it off entirely and still get just as much control as on the 600D.

Further updates and improvements
Aside from these headline features, the EOS 650D gains several new tweaks and updates. It uses Canon's DIGIC 5 processor (as seen in the S100 and G1 X compacts), which helps enable a boost in the sensitivity range to ISO 12,800 (25,600 extended), and allows correction for chromatic aberration in the camera's JPEG processing to give cleaner-looking images. The 'conventional' autofocus system for eye-level shooting is borrowed from the EOS 60D, and uses nine focus points which are now all cross-type, with the center point offering additional accuracy with fast lenses. The rear screen has been improved too, with no air gap between the display and cover glass, which should reduce reflections and improve visibility in bright light. There's also an anti-smudge coating in an attempt to reduce the impact of its newfound touch-sensitivity.
The camera also gains a built-in stereo microphone to provide sound for video, and a slightly-tweaked control layout that makes movie recording more accessible by placing it as a third position on the main power switch, as opposed to an exposure mode on the top dial. The 650D retains its predecessor's mic socket if you need better sound than the internal mics can offer.

There are a couple of new scene modes in its place, 'HDR Backlight' and 'Handheld Night Scene', both of which combine multiple exposures to give a final processed image. A four-exposure 'Multi Shot Noise Reduction' setting is also available in the PASM modes, unusually placed as an option in the High ISO Noise Reduction menu screen (and for JPEG shooting only, not RAW). There are also two additional processing filters but, as has been the case with previous Canon DSLRs, these are after-effects, rather than live previewed effects.

As is Canon's way, the EOS 650D won't directly replace the EOS 600D in the overall lineup. Instead the older model will remain in the line and effectively drop down a notch to the position currently occupied by the EOS 550D (T2i), which will be discontinued.

source: dpreview