VX2100 Megapixels count? at DVinfo.net

David Ho · January 20th, 2004, 04:17 AM

I was wondering what is the MP count (to be exact) for the VX2100 on taking still photo images? I would imagine it'd be a little over 1 megapixel?

Tom Hardwick · January 20th, 2004, 06:00 AM

The pixel count is 720 x 576, so as you can see it's well short of a megapixel count. But it doesn't stop there.
With a 3 CCD camera, there's a prism at the back of the lens that splits the light into red, green, and blue components, which then go to three CCDs. With a 1 CCD camera, the light hits a single CCD with red, green, and blue (or sometimes magenta, cyan, and yellow) filters over different CCDs.

This means that for every pixel on the 1-CCD camera, there are colours that are invisible to it. If a tiny spot of blue, say, happens to fall on a red-sensitive area of the CCD in the 1-CCD camera, then it will be lost from the image. But in a 3-CCD camera there are no such spots – colour sensitivity is uniform across the whole field.

This isn't quite as bad as it sounds, though. With very few exceptions, colour resolution is much less than black and white resolution in all video systems. In DV, colour has only 1/4 the resolution of luminance (brightness). But you still lose something.

More seriously, for a 1-chip camera to have the same luminance resolution, it has to have at least three times the number of pixels as a 3-ccd camera, which is still relatively unusual. So as you can see your VX2.1k produces stills that are better than the mathematical pixel count would lead you to believe.

tom.

David Ho · January 20th, 2004, 06:23 AM

Hmm...what camcorder would you say has the best digital stills taking feature? Probably the highest MP count thats a 3CCD?

Tom Hardwick · January 20th, 2004, 08:38 AM

Yes, so that would take you to the TRV950 and the Panasonic MX500. Both are poor in low light, which is why both come with built-in flash guns.

tom.

Mike Rehmus · January 20th, 2004, 11:24 AM

Theoretically, the response to, say, white light is uniform across the visual field of a 3-CCD camera but it usually isn't.

1. A CCD isn't a continuous plane of light sensors, they are sort of like little islands separated by lines of conductors. They have to be separated electrically or they would bleed charge between each diode site.

2. If the Optical sysem is free enough from internal blooming and glare then one might be able to see a light source that was small enough to discharge just a single diode.

3. Of course the light source would have to coincide with the location of the single diode.

4. If I were assembling the 3-CCD optical block, I'd consider (after testing the idea) aligning the diodes on the three chips so that they tended to cover the uncovered areas of the other 2 chips.

It would be interesting to move a columnated light source across the visual field of a few cameras and try to deduce how they are set up and to test the quality of the optics path with respect to resolution. This would require both a single spot and a line-pair source I'd think.

January 20th, 2004, 04:17 AM	#1
David Ho Major Player Join Date: Nov 2003 Location: Los Angeles, CA Posts: 354	VX2100 Megapixels count? I was wondering what is the MP count (to be exact) for the VX2100 on taking still photo images? I would imagine it'd be a little over 1 megapixel? __________________ "Everyone has a photographic memory. Some just don't have film."

January 20th, 2004, 06:23 AM	#3
David Ho Major Player Join Date: Nov 2003 Location: Los Angeles, CA Posts: 354	Hmm...what camcorder would you say has the best digital stills taking feature? Probably the highest MP count thats a 3CCD? __________________ "Everyone has a photographic memory. Some just don't have film."

January 20th, 2004, 11:24 AM	#5
Mike Rehmus Wrangler Join Date: May 2002 Location: Vallejo, California Posts: 4,049	Theoretically, the response to, say, white light is uniform across the visual field of a 3-CCD camera but it usually isn't. 1. A CCD isn't a continuous plane of light sensors, they are sort of like little islands separated by lines of conductors. They have to be separated electrically or they would bleed charge between each diode site. 2. If the Optical sysem is free enough from internal blooming and glare then one might be able to see a light source that was small enough to discharge just a single diode. 3. Of course the light source would have to coincide with the location of the single diode. 4. If I were assembling the 3-CCD optical block, I'd consider (after testing the idea) aligning the diodes on the three chips so that they tended to cover the uncovered areas of the other 2 chips. It would be interesting to move a columnated light source across the visual field of a few cameras and try to deduce how they are set up and to test the quality of the optics path with respect to resolution. This would require both a single spot and a line-pair source I'd think. __________________ Mike Rehmus Hey, I can see the carrot at the end of the tunnel!

January 20th, 2004, 06:00 AM	#2
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	The pixel count is 720 x 576, so as you can see it's well short of a megapixel count. But it doesn't stop there. With a 3 CCD camera, there's a prism at the back of the lens that splits the light into red, green, and blue components, which then go to three CCDs. With a 1 CCD camera, the light hits a single CCD with red, green, and blue (or sometimes magenta, cyan, and yellow) filters over different CCDs. This means that for every pixel on the 1-CCD camera, there are colours that are invisible to it. If a tiny spot of blue, say, happens to fall on a red-sensitive area of the CCD in the 1-CCD camera, then it will be lost from the image. But in a 3-CCD camera there are no such spots – colour sensitivity is uniform across the whole field. This isn't quite as bad as it sounds, though. With very few exceptions, colour resolution is much less than black and white resolution in all video systems. In DV, colour has only 1/4 the resolution of luminance (brightness). But you still lose something. More seriously, for a 1-chip camera to have the same luminance resolution, it has to have at least three times the number of pixels as a 3-ccd camera, which is still relatively unusual. So as you can see your VX2.1k produces stills that are better than the mathematical pixel count would lead you to believe. tom.

January 20th, 2004, 08:38 AM	#4
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	Yes, so that would take you to the TRV950 and the Panasonic MX500. Both are poor in low light, which is why both come with built-in flash guns. tom.