Ali Husain |
April 9th, 2007 03:18 AM |
tests of dynamic range with DVRack + comments
i put the camera through some tests with dvrack (non-hd) last week. watched the histogram through various modes and settings, locking exposure when needed for comparisons. some conclusions:
(1) cinemode definitely gives you a more linear exposure result, and it looks like more useable dynamic range. highlights don't clip as early; there are more detail in blacks. unlike the experience of someone in another thread: i see blacks at 0.
(2) the "custom" effects setting gives you more dynamic range if you lower the contrast to -1 in cinemode and tv modes (the ones that i tested). this is unlike the contrast control in, say, the panasonic gs400 which simply lowers the output range!
(3) it looks like the "brightness" in custom effects controls the auto-exposure... i set this to -1 because i prefer to keep the exposure out of the highlights as much as possible and postprocess for a less abrasive treatment of highlights, trading off, of course, more noise.
(4) this is a nasty one: when i perform a camera tilt (up and down motion) in cinemode i get noticeable transient image warping (a frame is squashed about 3% horizontally--it's skinnier for a frame or two) . when i get time i'll post an example. i can live with this though. it is an amazing camera.
some workflow comments:
- as noted in many posts: sony vegas doesn't yet support pull-down removal for this camera because of the missing flag in the mpeg stream and vegas's inability to force pull-down removal when it doesn't automatically detect it... so unless you do something else, you'll be looking at a gross 3-2 cadence.
- after reading one of david newman's posts about the hv20 and pull-down removal, the somethign else i decided to do was buy connect hd (had used the trial version a long time ago for a multi-cam hd project and was impressed). if you push the pull-down removal button you'll get beautiful 24p output that plays full-speed even on my not-latest hardware. (as an aside, i just upgraded to windows media player v11, before that with v10 it didn't quite play full-screen and full-speed).
- i use connect hd to capture footage and convert directly into CFHD without leaving behind an mt2s. it works pretty well although sometimes i get hangs during the capture (i need to file a ticket for that). it also looks like connect hd stops capturing and goes into convert mode whenever the total file size in the TEMP directory that it creates during capture equals 4gb, using in its calculations even leftover files from hangs (need to file a ticket for that too).
other observations:
- slight barrel distortion when full wide angle
- no noticeable chromatic abberation on wide (not like the xh-a/g1 with it's red-green separation)
- noise in lowlight is much more luma-oriented and agreeable than other cameras i've used (hvx200 for example).
- you couldn't bring this thing into a professional shoot without a bunch of black paint and a mattbox and important-looking things connected to it (and maybe lots of mumbling of "state of the art" and "hot technology")
- killer combination when paired with a merlin
- i have 24p slowmo footage from 60i-->60p that looks very very similar to almost identical footage i shot with the hvx200. remind me to post that comparison too. this camera is a ridiculous bargain.
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