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DVL-Digest 529 - Postings:
Index


DSR-PD150 test
DSR-PD150P test - (2)
DVCPro25 vs DVCPro50
filters


DSR-PD150 test - "Perry"

Adam Wilt posted:
>I just shot a resolution chart with a VX1000 and a VX2000 (NTSC). On the
wedges, my VX1000 fuzzes out to gray around 475 lines, with little aliasing
above that. With the VX2000, aliasing set in seriously at around 520 lines,
and persisted all the way to the 800 line limit of the chart. The wedge
*never* settled down to a smooth gray.<
{Perry}
Exactly what happened to my PAL test, although I used an uncalibrated chart
so I cannot tell you what the line count was. The curious thing was that
the aliasing on the PD150(VX2000) was very dependent on the setting of the
'Sharpness' control. This would suggest to me that it was occurring in the
downstream digital sampling rather than the CCD itself, and that therefore
the optical antialiasing may be effective AND transparent to the DV
sampling. There is definitely an optical antialias filter present, because
you can see its tell tale pattern on highlights, but it is not nearly as
obvious as for instance the JVC GY-DV500 where the antialiasing is very
solid.
HOWEVER at my advanced number of years I have forgotten far more than I
still retain, but I vaguely recall that Moiré type aliasing will only reveal
itself when the signal passes through a non linear stage to 'develop' the
signal products (the difference between the signal frequency and the sample
frequency). Is it possible that the aliasing components in the original
signal are being 'developed' by the significant non linearity of the
aperture correction?
What is certain is that good anti-alias filters are expensive and that the
VX2000 is very significantly cheaper than was the VX1000. Something has to
go!
{Adam}
>I didn't see huge difference in the white balance, though the VX2000 I
tested
seemed slightly bluer (!) than the VX1000.<
{Perry}
Unfortunately I only had the camera for a few hours and in retrospect I may
have had a custom setting when I did my initial 'default' test. The
PD150/VX2000 has an option to offset the auto AND manual white balance
settings in the 'Custom' menu, but these are calibrated by unmarked
'temperature' scales. The bottom line is that you can make the picture have
any reasonable 'look' you wish as long as it is on the blue(cold) thru
red(warm) axis. It was not that obvious (certainly to a hard pressed
tester) when the custom settings were in force, and by the time I had fully
mastered the menu system I had to pack the camera off to its next
destination.
Perry Mitchell
Video Facilities
http://www.perrybits.co.uk/



DSR-PD150P test - "Perry"

Ton Guiking posted:
>Of course the magazine has to have the first right for the article but...
eh... would you mind giving some ideas you have on this camera, esp. the
hiss problem....?<
What can you say - it hisses!! I cannot believe this will not get fixed.
Using a pro stereo mic, the hiss was probably acceptable but it sounds
pretty bad on the shipping mic. It is fine when switched to AGC so there is
obviously just a problem in the manual control circuitry. This facility is
one of the main reasons a broadcast pro would want to buy this camera.
Otherwise I would very happily buy one tomorrow if the VX-2000 wasn't there
for a lot less money. In good light the picture has an edge on my VX1000,
and there is more control. In any other sort of light it leaves the VX1000
standing.
Give it a few days and I'll post the review somewhere you folks can read it.
Maybe Alexei should open a companion to his GY-DV500 pages.
Perry Mitchell
Video Facilities
http://www.perrybits.co.uk/



DSR-PD150P test - "Adam J. Wilt"

> 1) It appears to have a lot less anti-aliasing optical filtering.
> This gives more resolution (from less pixels) than the VX1000 but
> obviously more aliasing.
I just shot a resolution chart with a VX1000 and a VX2000 (NTSC). On the
wedges, my VX1000 fuzzes out to gray around 475 lines, with little aliasing
above that. With the VX2000, aliasing set in seriously at around 520 lines,
and persisted all the way to the 800 line limit of the chart. The wedge
*never* settled down to a smooth gray.
I didn't see huge difference in the white balance, though the VX2000 I tested
seemed slightly bluer (!) than the VX1000.
Adam "We don't need no steenking optical antialiasing feelters!" Wilt



DVCPro25 vs DVCPro50 - "Adam J. Wilt"

> Yes, I know about all of the 4:1:1 vs 4:2:2 issues, they really
> will not apply here because we will not be editing in native DV.
If you're taking the video in on YUV or SDI, then the difference between
4:1:1 and 4:2:2 *will* be observable, and an experienced editor will see it.
> I need compelling reasons for shooting DVCPro50 over 25. Has anyone
> seen significant differences in artifacting of highly detailed scenes,
> etc.
Yes. Up close and personal, I can see noticeable mosquito noise on fine
detail in most scenes on DV25, and quilting artifacts on diagonals,
especially if sharpness is turned up. I have spent considerable time with my
eyes pressed to the monitor, yet I haven't seen *any* artifacts on DV50 (D-9
or DVCPRO50).
The general consensus (including tests done by the EBU) is that DV25 is
comparable to BetaSP, while DV50 is virtually indistinguishable from Digital
Betacam (at least for a couple of generations).
If you're doing the big national shows, shoot the best you can. DVCPRO50 also
upconverts to HD more cleanly than DV25 formats will.
Cheers,
Adam Wilt



filters - "Perry"

G Neilson [posted:
>as a beginner have i been recommended to buy a filter (or 2?) for my cam
(sony tr7000e)
if for nothing else, as a lens protector.
is there any i really should get?
grey-filter? UV? and what do they do?<
Photographic film has a substantial response in the UV, so a filter helps
preserve correct colors when UV is strong. CCD sensors have little response
to UV so a filter is not necessary.
However, as your advice suggests, a filter is cheaper than your lens and it
is usually easier to find a UV filter (often called 'Skylight') than a clear
glass one. You can then happily clean the filter glass with anything to
hand and not worry about scratching the front lens element.
A 'grey-filter' is properly called a 'Neutral Density' or 'ND'. It stops
down the light when it is too bright, but is really only of use when you can
manually control your iris. What is incredibly useful is a graduated
neutral density, or 'GradND' which come in various flavours and strengths
and often allow you to reduce the difference between bright and dark areas
of a scene and make it possible to record onto the limited Dynamic Range of
the video. Fully pro crews do this with lights, a suitable filter is a lot
cheaper and sometimes just as effective!
Unless you have a manual white balance mode on your camera, colored filters
are a waste of time since the camera will compensate. Soft focus fiters are
very difficult to use with consumer cameras because the depth of field is
too great. A good quality polariser can be useful, it darkens skies and
improves overall color saturation on outdoor scenes.
Perry Mitchell
Video Facilities
http://www.perrybits.co.uk/




(diese posts stammen von der DV-L Mailingliste - THX to Adam Wilt and Perry Mitchell :-)


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