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Tuesday, February 17, 2009

Straight To Video

The newest evolution in D-SLR technology has finally brought us high-definition video and stills in one camera. Here’s a look behind the scenes.

This Article Features Photo Zoom

“Because the D90 is an SLR that incorporates a mirror for viewing through-the-lens using an optical viewfinder,” says Silverman, “when Live View is engaged, the mirror swings up into a locked position, exposing the image sensor continuously to the light coming through the lens. For still image photography, the mirror must be briefly lowered before a picture is taken. This allows for auto exposure, auto white balance and, when applicable, Speedlight pre-flashes, to be performed after the mirror is lowered and just before the picture is taken. Then the mirror quickly returns to the up position after the image has been made and Live View resumes. When in D-movie recording mode, the mirror stays in the up position for the duration of the movie clip recording and the rear LCD is used for viewing the scene as it’s being recorded.”

The Canon EOS 5D Mark II’s image sensor features a piezoelectric element to eliminate dust. While it’s certainly an annoyance in still images, dust can be a devastating problem in video. The piezoelectric element activates any time the camera is turned on; you also can access it from the menu.

Canon EOS 5D Mark II
The Canon EOS 5D Mark II is the replacement to the popular full-frame original EOS 5D. The EOS 5D Mark II has a 21.1-megapixel, full-frame CMOS sensor, which includes the best image quality in the EOS D-SLR class, a self-cleaning sensor unit (the 5D did not), fast operation, a 3.0-inch, 920,000-dot LCD monitor, ISOs up to 25,600 and the ability to shoot 1920x1080p full HD video with mono or stereo sound (via a third-party external microphone).

The EOS 5D Mark II can shoot video at 30 fps in either 1920x1080-pixel full HD or SD video with a resolution of 640x480 pixels. The camera is limited in full HD video shooting time to 4 GB, or about 12 minutes. Canon recommends manual focus for video capture because autofocus is slow with video and could possibly defocus while shooting.

While shooting in video mode, you can adjust Picture Styles, white balance, AE lock, exposure compensation, peripheral illumination (vignetting) correction, Auto Lighting Optimizer and Highlight Tone Priority. Exposure mode is programmed AE; metering (via the image sensor) is center-weighted average. HD movies have a 16:9 aspect ratio, SD movies 4:3 and still images 3:2. The 3:2-ratio LCD monitor is letterboxed by a semi-transparent border in the appropriate aspect ratio during video shooting.


Nikon D90
The Nikon D90 was the first digital SLR released with video capture. It sports a newly developed DX-format, 12.3-megapixel CMOS image sensor with technology directly inherited from the highly touted, pro-level D300. Some of the features of the D90 include excellent still-image quality, fast operation, a self-cleaning image-sensor unit, a 3.0-inch, 920,000-dot LCD monitor, effective Active D-Lighting to control contrast and the ability to shoot 1280x720p HD video with monaural sound.

The D90 shoots HD video at 1280x720 or SD video at 640x424 or 320x216. It also shoots at the cinematic rate of 24 fps in .AVI format with Motion JPEG compression and mono sound (or without sound). HD videos have a wide-screen 16:9 aspect ratio, while standard videos have a 3:2 aspect ratio.

Videos can be shot in Program, Shutter Priority, Aperture Priority or Manual modes, only with Matrix metering. There’s no autofocus during video capture, but you can manually focus while shooting. The D90 is limited to 5 minutes of HD video capture and about 20 minutes during SD video mode.