I dont get it... Effective pixels
 

Hello, i have been watching a lot of specs of several cameras, and i found that the DVX100 have 380,000 effective pixels... now i watch some specs and i found that the TRV70 from sony have 1,000,000 effective aprox..

so, which camera has more resolution, or better video quality ?

leaving besides the 24p, audio quality, and just resolution and picture quality.

Thanks for all.

Note that Panasonic has 3 CCDs while the TRV70 has 1 CCD.

Plus, CCD's come in different sizes. The TRV70's CCD is smaller than that of a VX2000. The Panasonic DVX100 also has 3, 1/3" CCDs---much better low light plus a seperate CCD for red, green and blue (than the TRV70).

3 CCD cams usually capture better/richer footage, except for stills.

So what does all those numbers means, if one is 1mb effective, and another one is 380K effective, but still the 380k is better... well... i still dont get it, i do understand what you said, but still dont get how does it work, or how to choose between cameras..

Total number is the pixel count of the entire array on a CCD. Effective number is the amount actually used to generate the image. Basically there's a border of unused pixels all the way around the edges. That's the way it works, and it's pretty common to list both the total and effective pixel counts.

Three CCD's at 380,000 effective pixels each are generally considered better than a single CCD at 1 million pixels total. Unless that single chip has a primary color filter, but that's a whole other deal there.

Keep in mind that all CCD's are monochromatic, analog devices. They have to be told what "color" is, through overlay filters or prisms, and they need analog-to-digital converters (called A/D converters) in order to make digital video. Hope this helps,

Very interesting.. want more info .. mooore !!! ehhehehe

so let see.. even if 3CCDS are 380K they are better than 1M single CDD...

Does CDD improves DOF ?? i read that somewhere... dont sure...

what is that about advanced HAD CDD ? (Imaging Device: 1/3.6", 2110K Gross Pixels, Advanced HAD™ CCD) in the TRV70 ... i tried it today, but still it doesnt perform well at low light.. it has good DOF, but picture quality is not as good...

Better how?No. But a larger CCD gives you the option of getting a smaller DOF when the iris open.Don't get "HAD." You get what you pay for...most of the time. :)

Consumer cameras with built-in digital still cameras frequently have high pixel counts (i.e., 1 million pixels, or more).

Professional video cameras don't bother with including digital still cameras, they're only concerned with providing ultimate video quality, and professional cameras never bother with megapixel CCD's: they have just enough pixels to cover the frame.

In general, having a high-pixel-count CCD will harm video quality, by reducing low-light performance. Megapixel cameras usually have worse low-light performance.

The one exception is the new technology being employed in Panasonic and Sony cameras, to use the megapixel CCD in such a way as to provide high-quality 16x9 footage. For extracting high-quality 16x9, having a high-pixel-count CCD comes in handy, and for digital still photos a high-pixel-count CCD is good. But for regular video, the megapixel CCD's generally do more harm than good.

I actually have a TRV18... and i tested versus a TRV70, actually the old TRV18 model beat the shit out of the TRV70 in low light, but i dont have as good DOF as the 70...


I just cant wait to make some money and buy the DVX100, do you think it will lower up its price ?

btw (using the TRV18 with color correction, and magic bullet, gives me some nice results, of course, for tv propurses, not film)...

ok. thanks for all the tips, you cleared my head a lot.. thanks people...

<<<-- Originally posted by Barry Green : Professional video cameras don't bother with including digital still cameras, they're only concerned with providing ultimate video quality -->>>

My XL1s bothers with still shots :-p but you're probably just saying that a video camera Shouldn't focus on still photos, right?

Hi,

If I'm on the right track on what you guys are discussing, guess which cams has the most pixels ?

Yes, the 950 and PDX-10. They have 1Million x 3 !

Don't be misleading here, 1M CCD can definetly capture more details than 380K. The reason why the VX2000 is still better than TRV70 is because the current TV only support 530 horizontal scan line, and the 3CCD 380K VX2000 can provide enough detail for the maximum TV capacity. If you are using HDTV then the difference might be seen. Another thing be noticed is that no matter how high the effective CCD is , the DV format is always 720X480, so, you can see 38K is ok for that format. Although TRV70 can use 1M CCD for video capture, finally it has to be resized to 720X480. However theoretically the 1M CCD should provide better detail on good light conditions. BUt VX2000 are so good in their optics, color reproduction and other controls, that is why you see the VX2000 is better than TRV70, NOTE: the picture quality is not ONLY determined by the effective CCD, especially when the effective size is >380K and you are watching on normal TV:)

Hi Cooleye,

I did a side-by-side comparison at home last Saturday, the PD-150E and DCR-PC110E.

Guess what, it's quite difficult to tell which is which! Both the Sony cams deliver good images with roughly the same colormetri when we viewed them on a tv.

However, under low-light, PC110E is no match for the PD-150.

Our conclusion : The new breed of 1M-1CCD consumer cams can deliver good quality output that rival 3CCDs provided they are fed with enough lights. The only valid reasons left for buying a prosumer cam are better low-light and more manual controls.

I tried my old TRV18 vs a TRV70 and the TRV18 films better at low light than the new one.. but TRV70 have better DOF...

Megapixel CCD's hurt low-light performance. That's why you're finding better low-light performance on the older models.

It's all a tradeoff, Agus...

The way Sony single chip cameras capture color, is by using mosaic filters...that is, in front of each CCD 'pixel' sensor, there is either a Cyan, Magenta, Yellow or Green filter. Of course, the output image looks like a mosaic but the color for every pixel can then be ~approximated~ using a combination of the values from adjacent pixels.

Naturally, the larger the CCD and the more the resolution, the better the color approximation...but it will never ~theoretically~ reach the accurate color depiction of a 3CCD system, even though some single chip cameras with high pixel counts have pretty good color. The question you should ask yourself is, is it a good enough approximation for your application?

That said, and DV compression excluded(we're talking raw image from the CCD's here), a 1Megapixel CCD WILL capture more resolution detail than a 3CCD 380k system. The issue here is, that 3CCD systems are usually professional systems, and since you're aiming for television(ENG, whatever), the main issue is accurate (>near< broadcast standard)color representation. Not to mention, that looking at similarly priced camcorders, a 3CCD system will probably have smaller CCD's than a single-chipper of the same price for obvious reasons.

Note also, that 'detail' is kind of subjective. Above I used detail as in raw resolution...as in comparing two monochrome CCD's of different resolutions to each other...or comparing line-resolution. However, color representation also adds to the 'detail' that we subjectively see. Try comparing two pictures in your computer at the same resolution but at 4-bit color and 32-bit color and you'll see what I mean.
Even a 320x240 image will look amazingly good given millions of colors to work with.

And then you also have the issue of low-light sensitivity..the more dense the CCD(i.e.pixels/unit of area) usually the worse the low-light performance, because the individual pixel elements have less area to receive incoming photons.

Hope this helps.
Juan

Heard that after DV compression, the final captured images of Mega 1CCD cams are very close if not exceeding the 3CCD siblings, unless we have higher bandwidth format such as the 50mbps DVCPro

That is completely possible. I do not know the specific math, but it is probable that with a large enough CCD, the mosaic approximation gets good enough that the human eye cannot tell the difference between the approximation and a 3CCD setup.

Juan

There are many factors to consider. In a 3 chip camera each color has say 340,000 pixels (seems like a popular number). In your example of a four color Bayer matrix your million pixels are divided by 4, yielding only 250,000 per color. Signal to noise ratio is generally higher in 3 chip cameras also.

While single chip cameras do very well under many different shooting conditions, high contrast scenes generally suffer greatly. High contrast scenes shot with 3 chip cameras perform much better and capture greater detail, with lower noise.

To make things complicated, Sony's new DCR-PC300/330 has 2 MP effective pixels for video and uses RGB filter instead. Under sufficient lights, I guess this cam can really produce images that are very close to 3CCDs.

So, do we still need 3CCD cams in the very near future when all these Mega cams become so popular?

I think single chip cameras are the way of the future for professional use. It will take a couple of years, but eventually 3 chip cameras will fade away.

Well guys, I just ordered my 3 ccd DVX100 to get a decent camcorder for short movies, and now you all say that a new consumer 1 ccd camcorder will also do the job. ;-(

Peter

Peter,

There isn't a single 1CCD camcorder out there that can put out as good images as the DVX100. Some people might argue the new JVC HD is better, but if you put HD aside, the DVX has better color, 24P and great manual control which the JVC does not have. The JVC is indeed the first of a kind, but it is extremely buggy, to the point where it is pretty much unusable proffessionally.

You made a great buy...and you will know this when you get it. There's nothing quite like the DVX. :)

I guess what was meant on here is that 'someday' 1CCD cams might be as good or better than 3CCD cams, but not today.

Juan

Hi Juan,

That was already clear to me. I was just thinking of the fact that I had been thinking and counting a lot before doing such a big investment, and a couple of days later I read this forum thread.

I've already rented the DVX100 and know what a beauty it is.

Peter

Peter:

1 chip, 2 chip, 3 chip...

it's a red herring. The big news about the DVX100 CCD's is not that they are 3 chip, but they are progressive scan. That difference is much bigger than this chip count issue.

The fact that they are 24p progressive scan capable at under $20,000 is revolutionary.

Case in point...
 

I was playing with a Sony TRV19 (340k pixel 1 chipper) I just got for the experiment i'm doing, when I noticed something that might illustrate this whole effective pixel issue and one of the reasons why single chippers usually go towards larger pixel counts...

I had the camera on, aimed at the TV. Well, if you look at the red power LED on your TV through the camera, in a way such that the LED occupies approximately one pixel of the CCD(such that it looks very small), and then sloooowly move the camera up and down, or left and right, you will see the 'red' LED change colors.

The reason for this is that since the LED occupies approximately one pixel on the CCD(and the adjacent pixels are dark since it was a black TV), the ONLY data about the color of the LED is whichever color mosaic filter is in that particular CCD element. Thus, if you move the camera slowly up and down or left and right you should see a color sequence for the LED which corresponds to the mosaic configuration used in the camera. In my case it is Mg, Cy, Ye and G(i think).

Anyway, so this is a simple example of one of the problems of approximating colors with one chip. A simple solution, is to simply increase the effective pixel count, such that in the same situation as above, on say a TRV70, the LED would occupy at least 9 CCD elements, from which the actual LED color can be approximated regardless where on the chip it is. Of course, if you move farther away from the LED you can still get it to the point where it ocuppies one element and the problem is seen again, but the more the elements, the smaller the LED will be when the problem becomes apparent.

I hope this helps....
Juan

Nice experiment... thanks juan