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Canon GL Series DV Camcorders
Canon GL2, GL1 and PAL versions XM2, XM1.


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Old September 22nd, 2005, 12:55 PM   #1
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Widescreen

Can any of you clear this up once and for all?

I've seen a post or two on this site that says filming in 16:9 mode improves quality because less is captured and so compression is less. Bottom line, it's worth using if you want to view on a widescreen TV.

However this site:

http://www.farnfilm.com/widescreen.html

say it's verboten as a fifth is discarded but lines are duplicated to fill the space. The only way to do it is with a camera with 16:9 CCD's or use an anamorphic (?) lens attachment.

Am I reducing quality by using 16:9 mode on my XM2?

While I'm here, I saw somewhere how to convert the stretched footage captured in 16:9 mode but can't for the life of me find it again. I exported an iMovie 5 file to quicktime and set size to 720 x 405. It looked ok, but I'm no pro!

All help gratefully received (I'm starting to wish I'd taken the advice of a couple of members who said to buy the Sony HD instead of the XM2!!)

Cheers.
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Old September 22nd, 2005, 01:39 PM   #2
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Geoff,

A thread here was helpful for me in sorting this out. Filmmaker Jim Cole (whose trailer is the subject of the thread) jumps in at one point and shares a lot of great information. I've seen DVDs of both of these productions and Cole's results are thoroughly professional.

http://www.dvinfo.net/conf/showthread.php?t=40437

Leigh
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Old September 22nd, 2005, 03:22 PM   #3
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Geoff,
You'll certainly lose resolution if you shoot in 16:9 with the GL2. It doesn't have native 16:9 chips, so the picture is cropped top and borrom and then electronicaly stretched vertically to produce a full height anamorphic image which will play out fine on a widescreen tv.
It was this lack of decent 16:9 on my XM2 (PAL) that pushed me to buy the FX1. The widescreen images with this camera are really excellent - and that's just in Standard Definition!

Robin
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Old September 22nd, 2005, 04:29 PM   #4
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The dilema.....

"To answer your questions: "Day of the Scorpion" was cropped to 16:9 in post... "Sundowning" was shot using in-camera 16:9. The theory is that, since there is less actual data hitting the ccds when using in-camera widescreen, less compression is applied. Supposedly there's actually a gain in quality (this does not hold true for all cameras; i've been told to avoid it on a Sony.)"..... from the thread, thanks Leigh.

And Robin......

"Consumer DV camcorders are only capable of shooting in standard 4:3 ratio. When shooting in what’s called "16:9 mode”, the units perform a process of cropping the image top-and-bottom (so discarding approximately a fifth of the information) and expanding it to fit the screen by duplicating lines using a cheap DVE." from the link above.

Thank you both for your input. It seems to be a matter of opinion, but I thought science should have a definitive answer!!:)
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Old September 22nd, 2005, 04:50 PM   #5
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Quote:
Originally Posted by Geoff Holland
"Consumer DV camcorders are only capable of shooting in standard 4:3 ratio. When shooting in what’s called "16:9 mode”, the units perform a process of cropping the image top-and-bottom (so discarding approximately a fifth of the information)
This really isn't true. There are a number of consumer camcorders (depending on your definition of "consumer") that shoot real 16:9, including some inexpensive single chip models from Canon. Panasonic and Sony.

While their CCD's may be shaped in the 4:3 ratio, if they are high enough resolution it's possible to extract high quality 16:9. In the NTSC world that means you need to end up with at least 480 vertical lines in 16:9 mode. One clue as to which cameras can do this would be their resolution in still photo mode. If it's greater than 1 megapixel then there's a good chance the camera will do decent 16:9. Of course other design factors could prevent this (like electronic image stabilization), so be sure to read the manufacturer's specs.

For cameras like the GL2 and VX2100 however their older design CCD's only offer 480 lines in 4:3 mode, so shooting 16:9 crops this down to 360 lines which are stretched vertically back to 480 like Geoff says. However 480-360=120 unused lines in the black bars above and below the 16:9 image. Note that 120/480=.25, so you're losing 1/4 of your resolution instead of 1/5.
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Old September 23rd, 2005, 04:06 AM   #6
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Oh....

I thought the XM2 (pal) was rated as true 540 lines?

The more I delve into video, the more confusing it gets.... !!!
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Old September 23rd, 2005, 07:59 AM   #7
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I think that you may be confusing the number of vertical scan lines with the number of horizontal lines that can be resolved, eg. 540 horizontal lines of resolution...

Robin
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Old September 23rd, 2005, 01:08 PM   #8
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Er...

Bloody hell, my ignorance is worse than I thought....:)

I'm going to go and find some books and come back when I have an inkling about the subject....

The more I learn, the less I know....
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Old September 23rd, 2005, 01:31 PM   #9
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Geoff, these sites might help a little:

http://www.maxent.org/video/16x9.html

This one gets very involved, but answers many questions:

http://www.uwasa.fi/~f76998/video/conversion/
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Old September 27th, 2005, 01:17 PM   #10
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Head..... hurting....

Thanks all. I didn't know I was so dumb. I have so much to research and so little time!

I found this:

The following table summarizes a few of the more conventional analog HDTV proposals in comparison with existing TV systems[2]. (Note Grand Alliance and other fully digital proposals are not included in this table.)


Name Prog. Total Active Vert. Horz. Opt. Asp. Vert. Horz. freq.
or lines lines res. res. view ratio field field MHz
inter. dist.
HDTV p 1050 960 675 600 2.5H 16/9 23 deg 41 deg 8
USA,
analog
HDTV p 1250 1000 700 700 2.4 16/9 23 deg 41 deg 9
Europe,
analog
HDTV NHK i 1125 1080 540 600 3.3 16/9 17 deg 30 deg 20
NTSC i 525 484 242 330 7 4/3 8 deg 11 deg 4.2
conv.
NTSC p 525 484 340 330 5 4/3 12 deg 16 deg 4.2
prog.
PAL i 625 575 290 425 6 4/3 10 deg 13 deg 5.5
conv.
PAL prog p 625 575 400 425 4.3 4/3 13 deg 18 deg 5.5
SECAM i 625 575 290 465 6 4/3 10 deg 13 deg 6
conv.
SECAM p 625 575 400 465 4.3 4/3 13 deg 18 deg 6
prog

NOTE: The aspect ratio of the picture is defined to be the ratio of the picture width W to its height H. The optimal viewing distance (expressed in picture heights, H) is the distance at which the eye can just perceive the detail elements in the picture.


It may help some. It didn't help me.... which is why I'm asking for some more free advice (you lot should charge!)

My XM2 is PAL. If I capture in 16:9 mode, it will appear in iMovie 5 as a squished 4:3 movie. If I want to import that into iDVD as 16:9, I have to export the footage to QuickTime and muck about with the size (clicking the 16:9 button doesn't seem to do anything) When I manually fill in the size boxes, what would be the best numbers?

I promise that when I am properly schooled in this black art, I will give my help to apprentices free of charge...!!!

Last edited by Geoff Holland; September 27th, 2005 at 02:48 PM.
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