Canon just announced the world’s first DSLR with a Hybrid Autofocus. The Canon Rebel T4i, known as the EOS 650D in Europe, has an 18 megapixels CMOS sensor which can perform Phase-Detect autofocus in addition to the usual Contrast-Detect AF used during Live-View and Video-Capture. During normal photography, the T4i uses a 9 all-cross-point autofocus system, including a highly-sensitive double-cross center-point.
The Rebel T4i is the latest entry-level DSLR from Canon. It is relatively compact for a DSLR with a single control-dial and a lightweight plastic body. This DSLR brings a 3″ LCD with 1 megapixels and 3:2 aspect ratio mounted on rotating hinge for flexible viewing. This is also the first touch-screen to appear on a DSLR. A new processor lets the T4i support a native ISO sensitivity of 100-12800, expandable to 25600, and both 5 FPS continuous shooting and full 1080p HD video capture with stereo sound.
The Hybrid Autofocus sensor can perform Phase-Detect AF right on the sensor in addition to the usual Contrast-Detect AF used during Live-View and Video capture. According to Canon, the sensor’s Phase-Detect AF is not precise enough to focus accurate and it is therefore used to approximately focus very quickly. Contrast-Detect AF then refines focus until a precise lock is achieved. It turns out that the fast and quiet USM motors used in Canon’s high-end lenses is not adequate for this kind of focusing and so they also launched two new lenses with stepping motors (STM): the Canon EF-S 18-135mm F/3.5-5.6 IS STM and the first pancake lens in t he Canon lineup, the EF 40mm F/2.8 STM. With these lenses, focusing for video and Live-View should be much faster but will not remove the disturbing back-and-forth movement of Contrast-Detect AF during video recording.
Digital cameras are very much technology driven. The first Hybrid AF sensor was actually a SuperCCD developped by Fuji for their Finepix F300 EXR. Oddly, Fuji never replicated with in their CMOS sensors, so all their current premium compacts use slow Contrast-Detect autofocus. However, Nikon managed when they launched the fastest-focusing digital cameras ever made. The system used in the V1 and J1 can precisely lock focus without assistance, so Canon still has some catching up to do and so does Fuji.
With the Canon Rebel T4i and newly introduced STM lenses, there is a clear emphasis on video performance which is needed to convince more camera buyers to upgrade from fixed-lens cameras to DSLRs. Of course, image quality has always been the major draw and reason why so many people put up with the increased bulk. However, the loss of video features is concerning to those who wish to avoid carrying a large camera plus a video camera.
The Rebel T4i is scheduled to ship this moth for $849 USD or $1199 with the new 18-135mm F/3.5-5.6 IS STM lens.