As for memory capacity, the Canon EOS-1D X has two UDMA 7-compliant CF slots, and the Nikon D4 has one UDMA 7-compliant CF slot and one slot for the new XQD cards. The Sigma SD1 provides a single CompactFlash slot (UDMA 6-compatible), and the Sony A77 has a single slot that accepts SD/SDHX/SDXC (UHS-I) cards and Sony Memory Stick PRO Duo and PRO-HG Duo cards.
HD Video Capabilities In Pro DSLRs
The HD video capabilities of DSLRs continue to improve dramatically, and it's becoming an ever more important part of professional photography. Of the four cameras we spotlight in this article, only the Sigma lacks HD video capability.
The Canon EOS-1D X can do 1920x1080p video at 30 and 24 fps (25 fps in PAL), as well as 1280x720p HD at 60 (50) fps and 640x480 SD at 30 (25) fps, all in H.264/MPEG-4 AVC MOV format. For the first time, you can choose between All-I and IPB compression—All-I compresses each frame for easier editing and frame extraction (albeit with larger file size); IPB compresses frames by reference to previous and succeeding frames, providing smaller file sizes. Mono Linear PCM sound is possible via a built-in microphone, or you can connect an external stereo mic via a built-in jack, and you can adjust the volume while shooting. Exposure is manual or program AE; focus is manual or phase-detection before shooting or contrast-based before or during.
The Nikon D4 can do 1920x1080p full HD video at 30 and 24 fps, and 1280x720p HD at 30 and 60 fps, with mono Linear PCM audio via a built-in mic or stereo via an external mic. There are on-screen audio level meters, and you can connect headphones to monitor audio. You can focus videos manually or use single-shot or full-time servo contrast-based AF while shooting. You can record uncompressed 8-bit, 4:2:2 video directly to an external recording device via the D4's HDMI output. Especially nice is a choice of video recording crops: FX full-frame, 1.5x DX and 2.7x crop. This lets you effectively change focal lengths without changing the lens on the camera, all at full HD resolution.
The Sony SLT-A77 has some unique video features among DSLRs, one being full-time continuous phase-detection AF during video with eye-level viewing. Another is a three-way, tilting external LCD monitor, handy for odd-angle shooting. The new AVCHD Ver. 2.0 Progressive format allows the A77 to do 1920x1080 full HD video at 60p, as well as 60i and 24p; the camera also can do MP4 video (1440x1080 at 30 fps and 640x480 at 30 fps). You can record stereo sound via a built-in mic or an external mic, and you can shoot video in manual exposure mode or with program, shutter- or aperture-priority AE.
The EOS-1D X and D4 are full-frame cameras; the A77 is APS-C. This means their sensors are larger than those of most pro camcorders and thus able to produce narrower depth of field for selective focus and a cinematic look that's difficult to get with smaller sensors. All offer a wide range of lenses, all of which can be used for video.
In these days of ever-increasing secrecy on the part of the camera manufacturers—and ever-easier access to online blogs and rumor sites—it's both harder and easier than back in the day to guesstimate what may be coming next. As we produce this issue, the rumor mills are swirling with the following guesses:
Canon EOS 5D Mark II Replacement—Similar features to the EOS 5D Mark II, but better AF, 4K video and more megapixels (either marginally more or 30+).
Nikon D700 Replacement—Similar to the D700, but with improved HD video and either a similar sensor to that in the D4 or one with 30+ megapixels.
Sony SLT-A99—The first full-frame, fixed-translucent-mirror DSLR, with a very high megapixel count (a full-frame sensor with the same-size pixels as the A77's APS-C sensor would have about 57 megapixels), solid pro body and video with full-time phase-detection AF and eye-level viewing.