I have a Sharp Viewcam VL-Z1 and it has been an excellent entry level
camcorder with superb picture quality for the price. Like many other
camcorders it claims to have a 16x9 recording option and I'm wondering
whether this is a true 16x9 recording and uses all the pixels to
provide that resolution or does it simply add black bars at the top?

My understanding is that the vertical resolution is approximately 480
lines. I'm not sure if these DV cameras will then utilize all 480
lines to record for widescreen or whether the 480 is just shaved
down/cropped to whatever would be the respective number of lines for
the same horizontal scanning. Anyone have any idea? Are there
camcorders that will use the true full resolution and do good
widescreen?

Now if I continue using this camcorder, should I just continue
recording in 4:3 instead of 16x9 since at least I'll get better
resolution recordings which I can always crop later? I'm curious to
know if anyone has answers for this...

On Sun, 01 May 2005 02:18:57 -0400, JSOUL dot com
<tkdREMOVESPAMinthecity@yahSPAMoo.com> wrote:

No cheap camera has true 16:9. It's all derived from a bunch of lines
in the middle of the CCD. If you want to get some better 16:9, either
buy something like a Sony PDX-10, or a optical 16:9 adapter, like a
Century Optics (but there are cheaper ones too).

cheers

-martin-

On Sun, 01 May 2005 02:18:57 -0400, JSOUL dot com
<tkdREMOVESPAMinthecity@yahSPAMoo.com> wrote:

Show quoteHide quoteThe "film" in the camera is 4:3.    If it used the full height of the
sensor in 16:9 mode, the sensor would have to magically grow sideways.
This is unlikely to happen.  

You can crop the vertical height in the camera, or you can crop it in
editing.    I'm not sure if or why one or the other would give better
results?  Try.

In the early days of CCD cameras that had the 16 x 9 option
There were barely enough pixels in the camera to be able to
have a 1 to 1 relationship between the CCD and the output
resolution. Some had some extra pixels that were used for the
image stabilization function, but that was it. What the did to
simulate the 16 x 9 format was to crop out the top and bottom
and then interpolate the result back up to the needed 480 lines
before putting it on tape. When you look at the picture in the
viewfinder while switching from 4 x 3 to 16 x  9 you would notice
that the horizontal field of view stays the same while the vertical
coverage is reduced.

You would expect a true 16 x 9 format camera to keep the vertical
coverage to stay constant and the horizontal coverage to get wider.
I don't know of any consumer, or even prosumer cameras that can
actually do this. However, you have to think a little differently about
this today.

Most cameras today have many more pixels than the actual output
resolution would call for. They are averaging and interpolating all
of the time now. By having more resolution on the chips they can
actually improve the picture quality. One big benefit of the higher
resolution chips is that the aliasing can be reduced (the jagged
look you get on diagonal lines like you would see when shooting
a house with vinyl siding).

Some of the cameras, like the PDX-10 mentioned earlier,
actually have enough horizontal pixels on the chip to make a
true 16 x 9 image and still have a 1 to 1 or better relationship
with the output resolution. The TRV-950 is nearly the same
camera as the PDX-10, and has the same chip, AFAIK.
On the PDX-10 the picture does get wider when you switch
from 3 x 4 to 16 x 9, but not on the TRV-950. The difference
is how the chip is used. If you look at the examples on my
web site http://www.techshop.net/PDX-10/ you will see what
is happening there. They both use a similar amount of the chip
for the 3 x 4 image but the PDX-10 uses more for the 16 x 9
image while the TRV-950 uses considerably less for 16 x 9.

Perhaps this allows them to use chips with more flaws at the
edges on the cheaper camera, but they both have the same
resolution when shooting stills. Actually, I used the resolution
of the stills to derive the information on this page, but the
actual resolution of the chip may well be even higher. In either
case you will notice that the horizontal resolution that is used
for 16 x 9 is higher than the output resolution needed (720 for
both PAL and NTSC). In both cases they are interpolating,
but they are averaging down, not up.

So, it isn't like they are taking an image that is 480 pixels
high and cutting off the top and bottom and then stretching it
out to fill the 480 needed for output. Even in the worst case,
they are taking a picture that is 528 and squeezing it to 480
for NTSC, but it would appear that there would be a tiny bit
of stretching to achieve the PAL image.

David

Some video cameras use high-density 4:3 CCD's and simply sample "whatever"
aspect ratio is being selected.
(XL2 comes to mind)

Good approach as 4:3 chips are cheaper due to economies of scale than 16:9
chips.

FYI, Adam Wilt has a great page on the vagaries of 16:9 mode in video
cameras. http://www.adamwilt.com/DV-FAQ-etc.html#widescreen
He mentions some ambiguity about how Sony D8's (older ones at least) achieve
16:9.

Here's a link to dispell that:
http://www.camcorderinfo.com/bbs/archive/index.php/t-111122.html
Adam's suggestion is correct - those cameras (1st, 2nd gen D8's) disable EIS
and sample extra horizontal width.
I've tested this on various models and you can do the same on yours.

Put your cam on a tripod or at least ensure it won't move. Switch between
4:3 and 16:9. Look for an increase in horizontal angle of view.
FYI: I shot a concert in 16:9 with a D8 and had wonderful results. Take a
look at this page: http://www.ncf.ca/~af895/misc/rasputins/rasputins.html

C.



Show quoteHide quote

Thanks for all of your posts as they have been very helpful. I did the
16:9 versus 4:3 test and did not see any perceptible increase in
horizontal view with this camera. I just got black bars on the top and
bottom of the screen. Not surprising.

While it retailed for $500 when it came out a few years ago, I don't
doubt that if it was cheaper to just crop the picture and technically
market it as being able to shoot 16:9, that this was done (without
alerting the purchaser that these modes were not truly equivalent.)

On Sun, 1 May 2005 10:47:53 -0400, "C.J.Patten"
<cjpatten@KNOWSPAMrogers.com> wrote:

Show quoteHide quote

JSOUL dot com <tkdREMOVESPAMinthecity@yahSPAMoo.com> writes:
Are the black bars on the top and bottom of the TV screen, or just the
viewfinder?

When you switch the camera to widescreen mode, it should produce an
image that still fills the height of the video frame, but looks somewhat
"squished" vertically.  This can then be stretched back to the correct
shape on a widescreen-capable TV.  If your TV actally has a 16:9 screen,
this fills the whole screen area with no black bars.  But none of the
lines of video from the camcorder should be black.

If your TV is really 4:3, then it may leave black bars top and bottom,
but this is really an artifact of not having a WS TV.  Similarly, if the
camcorder's viewfinder is really 4:3, it may display black bars when the
camera is in 16:9 mode, but the *video* produced should have all lines
non-black.

If the camcorder is putting out video that has black bars *in the
video*, that's not proper widescreen at all, and it's useless.

On the other hand, there are several ways that the camera can internally
produce widescreen output.  The worst is to take 3/4 the usual number of
scanlines from the CCD and interpolate vertically to reduce the vertical
field of view.  This reduces vertical resolution *and* vertical FOV,
neither of which is useful.  Better is to capture the image from more
horizontal width of the CCD and compress the image horizontally to fit.
This leaves vertical resolution and FOV the same, increases horizontal
FOV, and may or may not increase horizontal resolution.

    Dave

Video XFer to Laptop - Firewire or USB?
DVD language *titling* options
Looking back... (and FYI Tom)
i.Link (ieee 1394) video capture software
Sony PC-100 vs newer DV camcorder
Why must an .MPEG file be transcoded before burning to DVD? How can I prevent this requirement?
sit-rep ... camera in pieces
Windows XP not seeing my DV camera
DVD-R blanks compatible with LiteOn 5005
DVR Recording on Cox Digital and Watching another program