GS300 16:9 wider than 4:3, how? at DVinfo.net

Kevin Janisch · August 4th, 2006, 12:50 PM

Just received my GS300 today and I'm amazed at how small this 3CCD camera is (I also own a Canon XL2 for business, the GS300 is for family vids). Anyhow, doing some tests as to whether to use 4:3 or 16:9 mode. How can the 16:9 mode have a wider field of view than 4:3? Isn't it just the 4:3 image cropped and zoomed to produce 16:9? Where is the extra image on the edges coming from? I'm getting much more image from the left side of the frame than the right (viewed on PC, so it's not overscan).

I anticipated the possiblity of just using 4:3 to keep the resolution and crop it later in post if I wanted widescreen, but since I'm getting more image on the edges (making up for the loss in vertical resolution) I may just go 16:9 and save myself the hassle.

Thanks.

Kevin

Boyd Ostroff · August 4th, 2006, 02:00 PM

Sounds like your camera is really doing native widescreen by using extra pixels on the CCD to the left and right of the 4:3 image. For a test, does this camera have a still photo mode? If so, lock it down on a tripod, shoot a few seconds of 4:3 video, then a few seconds of 16:9 video and finally a still photo. Now compare the 3. If you overlay on separate layers in Photoshop and do some scaling so they match then you'll see what's going on. I suspect the camera only uses the center portion of the CCD in 4:3 mode.

I did something like this to figure out how the PDX-10 samples the CCD's in the different modes:

http://www.greenmist.com/dv/16x9/10.JPG

Kevin Janisch · August 7th, 2006, 02:25 PM

Thanks Boyd

Peter Jefferson · August 11th, 2006, 05:43 AM

from the MX300 onwards (i think) all the cameras of the MX and GS range had native 16:9. The CCD is actualy oversampling the area then discarding what it doesnt need for 4:3..

Its funny though, youd thing they woulda done this with the DVX100 and DVC30, but they didnt..

Frank Granovski · August 11th, 2006, 05:56 AM

The MX300 just cuts out an area of the CCDs for the 16:9. I'm not sure but I think the PV-DV953/MX5 does the same thing with smaller CCDs but with more pixels.

Guy Bruner · August 11th, 2006, 08:02 AM

Yes, Frank. All the Panasonic cams use 4:3 CCDs.

Frank Granovski · August 11th, 2006, 08:39 AM

Really? Surely you jest.

Chris Barcellos · August 11th, 2006, 09:38 AM

Okay, technically, isn't 4:3 DV and 16:9 DV actually "packed" in the same size frame pixel wise, with the 16:9 having a different aspect pixel, with some cameras doing 16:9 electronically (VX2000 for instance), and others actually using all pixels? Can some tech brain out there clarify this ?

Mack Fisher · August 11th, 2006, 10:37 AM

The same thing happends on Sony's HC1000, Your over sampeling your 4:3 censors for 16:9 and only using the center of that image to get 4:3.

Bogdan Vaglarov · August 11th, 2006, 10:09 PM

I have GS100 that was the first 'wide mode' cam from Pany I think.
In Cinema mode (found from the menu and not the direct button) the 4:3 is croped from up and down and apparently you use just the 4:3 part with reduced resolution (probably what any non 'wide' cam would do to simulate wide)
In wide/procinema mode the CCD area used is slightly widened and the vertical resolution reduced. This is even greater for the following models GS400, etc (wider part of the newer chips).

GS300 uses same size 1/6 inch CCDs so I suspect the implementation is almost same as GS100.
Notice that the pixels count (per CCD) is 800k but for video only 640k are used. For stils this changes to 700k so you can't rely on comparison with stills and video.
Now the Japanese pages for GS100 are gone and there were nice schems explaning the exact area and pixel cound of the CCDs used in the different modes.
Cheers, Bogdan

Edit: Here is copy from the GS300 specs (transformed from Japanese)

1/6'' CCDs
Total number: 800k×3、
Effective pixels:
Video: 640k×3（4:3）/540k×3（16:9）
Photo: 710k×3（4:3）/540k×3（16:9）

So may be you can compare Video to still in 16:9 as it seems it uses same area of the CCD!

Edit2: I forgot to mention and it is confirmed from the spec. This type of cams are not NATIVE wide - as you see there is resolution lost when using the wide mode.

August 4th, 2006, 12:50 PM	#1
Kevin Janisch Major Player Join Date: Jan 2004 Location: Monterey, CA Posts: 406	GS300 16:9 wider than 4:3, how? Just received my GS300 today and I'm amazed at how small this 3CCD camera is (I also own a Canon XL2 for business, the GS300 is for family vids). Anyhow, doing some tests as to whether to use 4:3 or 16:9 mode. How can the 16:9 mode have a wider field of view than 4:3? Isn't it just the 4:3 image cropped and zoomed to produce 16:9? Where is the extra image on the edges coming from? I'm getting much more image from the left side of the frame than the right (viewed on PC, so it's not overscan). I anticipated the possiblity of just using 4:3 to keep the resolution and crop it later in post if I wanted widescreen, but since I'm getting more image on the edges (making up for the loss in vertical resolution) I may just go 16:9 and save myself the hassle. Thanks. Kevin

August 11th, 2006, 09:38 AM	#8
Chris Barcellos Inner Circle Join Date: Nov 2005 Location: Elk Grove CA Posts: 6,838	Okay, technically, isn't 4:3 DV and 16:9 DV actually "packed" in the same size frame pixel wise, with the 16:9 having a different aspect pixel, with some cameras doing 16:9 electronically (VX2000 for instance), and others actually using all pixels? Can some tech brain out there clarify this ? __________________ Chris J. Barcellos

August 11th, 2006, 10:37 AM	#9
Mack Fisher Regular Crew Join Date: Mar 2006 Location: Seattle, WA Posts: 158	The same thing happends on Sony's HC1000, Your over sampeling your 4:3 censors for 16:9 and only using the center of that image to get 4:3. __________________ Northweststockfootage.com Shooting 100% HD Washington, Oregon, and Soon British Columbia

August 4th, 2006, 02:00 PM	#2
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,802	Sounds like your camera is really doing native widescreen by using extra pixels on the CCD to the left and right of the 4:3 image. For a test, does this camera have a still photo mode? If so, lock it down on a tripod, shoot a few seconds of 4:3 video, then a few seconds of 16:9 video and finally a still photo. Now compare the 3. If you overlay on separate layers in Photoshop and do some scaling so they match then you'll see what's going on. I suspect the camera only uses the center portion of the CCD in 4:3 mode. I did something like this to figure out how the PDX-10 samples the CCD's in the different modes: http://www.greenmist.com/dv/16x9/10.JPG

August 7th, 2006, 02:25 PM	#3
Kevin Janisch Major Player Join Date: Jan 2004 Location: Monterey, CA Posts: 406	Thanks Boyd

August 11th, 2006, 05:43 AM	#4
Peter Jefferson Inner Circle Join Date: Apr 2003 Location: Aus Posts: 3,884	from the MX300 onwards (i think) all the cameras of the MX and GS range had native 16:9. The CCD is actualy oversampling the area then discarding what it doesnt need for 4:3.. Its funny though, youd thing they woulda done this with the DVX100 and DVC30, but they didnt..

August 11th, 2006, 05:56 AM	#5
Frank Granovski Outer Circle Join Date: May 2002 Location: Hope, BC Posts: 7,524	The MX300 just cuts out an area of the CCDs for the 16:9. I'm not sure but I think the PV-DV953/MX5 does the same thing with smaller CCDs but with more pixels.

August 11th, 2006, 08:02 AM	#6
Guy Bruner Major Player Join Date: Nov 2003 Location: Ashford, AL Posts: 937	Yes, Frank. All the Panasonic cams use 4:3 CCDs.

August 11th, 2006, 08:39 AM	#7
Frank Granovski Outer Circle Join Date: May 2002 Location: Hope, BC Posts: 7,524	Really? Surely you jest.

August 11th, 2006, 10:09 PM	#10
Bogdan Vaglarov Major Player Join Date: Jul 2003 Location: Yokohama, Japan Posts: 366	I have GS100 that was the first 'wide mode' cam from Pany I think. In Cinema mode (found from the menu and not the direct button) the 4:3 is croped from up and down and apparently you use just the 4:3 part with reduced resolution (probably what any non 'wide' cam would do to simulate wide) In wide/procinema mode the CCD area used is slightly widened and the vertical resolution reduced. This is even greater for the following models GS400, etc (wider part of the newer chips). GS300 uses same size 1/6 inch CCDs so I suspect the implementation is almost same as GS100. Notice that the pixels count (per CCD) is 800k but for video only 640k are used. For stils this changes to 700k so you can't rely on comparison with stills and video. Now the Japanese pages for GS100 are gone and there were nice schems explaning the exact area and pixel cound of the CCDs used in the different modes. Cheers, Bogdan Edit: Here is copy from the GS300 specs (transformed from Japanese) 1/6'' CCDs Total number: 800k×3、 Effective pixels: Video: 640k×3（4:3）/540k×3（16:9） Photo: 710k×3（4:3）/540k×3（16:9） So may be you can compare Video to still in 16:9 as it seems it uses same area of the CCD! Edit2: I forgot to mention and it is confirmed from the spec. This type of cams are not NATIVE wide - as you see there is resolution lost when using the wide mode.