Quote:
Originally Posted by Jason Dunn
I finally got some hands-on time with the GH1 at a recent digital photography show in Calgary...quite a nice little camera! So you're saying it does autofocus on videos?
|
The entire AF system is contrast-detect since there's no mirror. So you get the same AF performance with video as you do with stills, though I assume you probably still have to "tell" it to re-focus (no subject tracking) which is both good and bad. DSLR's use a phase-detect system using a dedicated sensor, though the newer one's also implement a comparably weak contrast-detect mechanism for live view and video. Supposedly the Micro Four Thirds' AF is pretty darned comparable to entry-level DSLRs in terms of speed and perhaps better in terms of accuracy.
Incidentally, I just got an EOS 7D (woot!!!) and it does allow for real-time AF during video capture. It requires that you press the AF-ON button, it takes a couple seconds (variable between near instant and around 3 seconds depending on the distance between the old and new subject), and if you use the internal mic you can most certainly hear the AF motor seeking (even on the "silent" USM lenses), but it does work and the resulting video quality is truly stunning. It works passably for distant subjects and kind of painfully for closeup ones. It ain't gonna replace the dedicated video camera any time soon for home videos, but since the best (video) camera is the one you have with you...
Regardless, I agree with you that DSLR video needs to evolve. I really don't understand why the contrast detection AF in this thing can't be as good (or better) than the GH1. It's got relatively massive computing power in the DIGIC chips. Maybe a bit of tweaking and a firmware upgrade? More likely a dedicated processor is required, and thus a 7D mkII. Oh well, I got it for the stills...which are a major (I mean MAJOR) step up from my old Rebel, especially in terms of proper lighting (even backlit subjects always seem to come out perfectly exposed) and white-balance. I've got a couple of friends with D300's and I intend to make them jealous (yeah, right, you Nikon folks always find something to feel superior about).
