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Tuesday, November 2, 2010

Camera Tech You Need To Know About

These days, a lot of innovation in photography is starting out in lower-end cameras. Some of these features are going to change the way you work as a pro.

This Article Features Photo Zoom

Built-in features like auto HDR (a mode in the Pentax K-5) will become increasingly useful to pros.
Of course, the real proof is in the pudding, and the quality of video from DSLRs can be outstanding. The problems are most visible with subjects containing fine detail. Shots of people tend not to show problematic artifacts as readily. Professional cinematographers do use HD DSLRs for pro video—you’ve probably heard that the 2009-2010 season finale of the TV series House was shot with Canon EOS 5D Mark II cameras—and commercials and even portions of feature films are also being shot with DSLRs, taking advantage of the good high ISO performance, shallow depth of field, compact camera size (compared to pro HD camcorders), wide range of interchangeable lenses and greatly reduced cost.

Ultimately, we expect that HD video in DSLRs is here to stay, and new high-end models that come along are likely to have the functionality built in. On balance, it’s a useful feature, and as a professional photographer, you can decide how much or how little you want to delve into video.

AF Advancements In Video Mode
One drawback to video with DSLRs has been the slow to nonexistent autofocusing during video recording. DSLRs use phase-detection AF for still photos because it’s quicker and more accurate than contrast-based AF, and is very effective with action subjects. The problem is that the SLR mirror has to be in the down (viewing) position for the phase-detection AF sensor to function, while the mir-
ror has to be in the up (recording) position in the video-recording mode. The upshot is that phase-detection AF hasn’t been available while you’re shooting video with a DSLR.

So DSLR makers have offered two AF options in Live View mode: phase-detection, with the drawback that the live view is momentarily disrupted while the camera focuses; and contrast-based, which reads contrast at the image sensor and doesn’t affect the live view, but which is slower than phase-detection AF. Obviously, phase-detection AF can’t be used during video recording—the video would be disrupted each time the camera focused.

DSLRs like the Nikon D3S shoot HD video.
Contrast-based AF has improved a lot in recent years, and Panasonic’s version (in all their Micro Four Thirds System mirrorless cameras) is surprisingly quick. And Nikon’s new D3100 and D7000 DSLRs provide AF-S full-time, contrast-based servo autofocusing during video recording. These AF capabilities aren’t on par with those of pro HD camcorders (and much pro video work is done with manual focusing), but it’s progress since the first video DSLRs couldn’t autofocus at all during recording. Look for better video autofocusing capabilities in future professional-level HD DSLRs.

Sony’s new SLT-A55 and SLT-A33, with their fixed pellicle mirrors and electronic viewfinders, can use the camera’s phase-detection AF for both still and video shooting, with no disruption, even with moving subjects. And you get convenient eye-level viewing via the EVF.

Panasonic states that the Light Speed contrast-based AF system in its new Lumix DMC-GH2 mirrorless camera is faster than high-end DSLR phase detection. We haven’t seen that camera yet, but are eagerly awaiting its arrival.


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