Re: [Debconf-video] Report from last week-end's single-user single-day DebConf Video sprint
On 2017-06-27 13:26:37 (+0200), Wouter Verhelst <w@uter.be> wrote:
> On Tue, Jun 27, 2017 at 12:51:40AM +0200, Nicolas Dandrimont wrote:
> > Hey all,
> >
> > I've spent an evening and a day working on video stuff last week-end, using the
> > opportunity of a pair of lent cameras to do some work. I've put some pictures
> > up at https://krkr.eu/dcvideo/
> >
> > Here's what I can report:
> >
> > Camera testing
> > --------------
> >
> > I had both the Sony PXW-X70 and the JVC GY-HM200E set up. Both cameras are
> > largely similar in functionality and feature set, and they work just fine with
> > the vocto setup.
> >
> > I recorded to YouTube : https://youtu.be/BleLh5hXICY; at the beginning of the
> > video, the JVC is on the left, the Sony on the right; I switched them out at 12
> > minutes : most of the video has Sony on the left and JVC on the right.
> >
> > The differences I could notice were:
> >
> > - Low light behavior: using dawn and the blinds in the room allowed me to test
> > for crappy light conditions
> >
> > (reminder: at those timecodes, Left = Sony, Right = JVC)
> > test 1 : https://youtu.be/BleLh5hXICY?t=9282
> > test 2 : https://youtu.be/BleLh5hXICY?t=10293
> >
> > feel free to stroll through that video for more tests.
> >
> > What I noticed:
> >
> > The JVC high gain for low light setting is manual and fiddly; Sony has proper
> > automatic gain control. The JVC's auto white balance is slow, the Sony seems to
> > do the right thing pretty fast even in very bad conditions (playing with
> > blinds, light switches, ...). The JVC also was very grainy when fully zoomed in
> > and in low light (see the very beginning of the video).
>
> In addition, the JVC's autofocus seems pretty bad, often requiring
> several seconds to be done; the Sony seems faster in that regard.
>
> Its grainyness is due to the larger sensor on the Sony; that's perfectly
> expected behaviour (and is why my friend suggested the Sony in the first
> place).
>
> I notice that the JVC seems to be able to zoom in further; is that a
> correct assessment? Given that it has a smaller sensor, this is also to
> be expected; but given that the Sony's sensor can do 4K and we only need
> 720p, we can probably get away with so-called "digital" zoom without
> that much quality loss (there will be some optical artifacts, but not
> really something you'd call showstoppers)
>
> Did you run a test on how far away you can get a close-up of someone?
>
> > - Size: the Sony is substantially smaller than the JVC and we should be able to
> > fit two in a case the size of the ones we've been using for the dvswitch
> > laptops.
>
> That's good, yes :-)
>
> > - SDI connectivity: the Sony does SDI-6g (up to 4k) while the JVC does not
> > (AFAICT, pegging the SDI to 1080p). Not very useful for us, but who knows
> > what we'll do in the future...
>
> Right, but I doubt we'll ever want to do more than 1080p (if even that),
> so it shouldn't matter at all.
>
> > - Audio input setup: I only had batteries for the tests (no AC adapter) and I
> > noticed the Sony would lose audio input settings when rebooting. As it
> > defaulted to shoe mic it's not a showstopper.
>
> It is a bit annoying, and might be confusing. There is a slight risk of
> people switching off the camera and thereby losing settings, resulting
> in the recording not being the way it should be.
>
> I agree it's not a showstopper, but it is something we need to make sure
> we've got covered for volunteers; we should tell them never ever ever to
> switch off the camera, or have a cheat-sheet of "post-boot operations"
> with every camera.
>
> Probably best to do the latter, actually.
Rather than routing the audio through the camera, maybe just get something
like this: https://global.focusrite.com/usb-audio-interfaces/scarlett-2i2
or a version with more interfaces and feed the audio directly into the mixer
PC. I think this should also make cabling a little easier. Using a version
with more inputs, would also allow us to feed the environment audio directly
into the mixer PC, simplifying the audio mixer setup.
Peter.
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