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digicam ccds in dvcams?

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dpopiz

Diamond Member
I'm not so sure this is the right place to post this question, especially since it's not really computer-related...and it's not highly technical, but I think this is the most appropriate forum to put it in.

I was just wondering what the difference is between CCDs used in digicams and the ones used in dv cameras. Why can't those beautiful high-quality CCDs be used for dvcams?
 
probably because the processing power would be to great for the slow processor in a movie camera. It would also kill the battery life.
 
more processing power? aren't the ccds in digicams just better quality than the ones in video cameras?
 
no....my $200 olympus digicam by far has better quality, not res than even the $2000 semipro dvcams I've tried at fry's
 
quality doing what? recording video? low resolution mpeg2 recorded on dv cams already eat up huge amounts of data, more then dvd since its not VBR. we don't have high resolution video storage capability yet.
 
dv cams don't use mpeg2. they use dv....any way I'm not talking about compression quality. (dv is near-lossless anyway) I'm talking about the quality of the CCD (its color definition, contrast accuracy, etc.)
 
Originally posted by: dpopiz
dv cams don't use mpeg2. they use dv....any way I'm not talking about compression quality. (dv is near-lossless anyway) I'm talking about the quality of the CCD (its color definition, contrast accuracy, etc.)
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hmm i'm no expert but i've always thought DV was high bitrate cbr mpeg 2. it certainly can't be raw video, data tapes aren't all that big yet. so i dunno, i could be wrong😛

as for ccds look at that foveon tech. sorta explains why nice dv cams use 3 ccds to capture the 3 primary colors separately. for video you need speed too i suppose😛 but in terms of resolution, you can't really fit 4-5mega pixel video streams on a consumer cam. data would be quite insane😛


 
GAH!!! sorry. I just don't think you're understanding what I mean and it makes me go crazy! 😉
I'm not talking about anything related to compression or resolution. If you've the pictures from a digicam compared to even a high-end dvcam, you can see that the way the ccd picks up light is clearly better in the digicam. Its images have much better color definition and don't suffer nearly so bad from contrast changes and imperfect lighting.

btw dv isn't mpeg2. it's "I-mpeg", which is similar to m-jpeg.
 
I understand where you're coming from, I have experience repairing both types but have never done engineering work related to them so here's my two cents-

Evadman is pretty much right on the money - the amount of data that would flow out of a 2 megapixel CCD device would be astronomical, and to have that amount of data flow at 25 or 30 frames per second would result in a huge amount of information requiring processing and storage.

Video cameras have high speed focal devices too, the focus is (almost always these days) obtained by the high frequency content coming from the CCD. You may notice video camera's have trouble focusing on objects with a very large matt finish, such as a wall without any pictures or features on it. Processing data at such a high frequency would be well out of reach of even a multiprocessor x86 system.

Video camera's also have to be quick to adjust the iris should a bright light suddenly appear, or should it suddenly go dark.

But I would think the main reason would be that DV is in the order of about 500 horizontal lines resolution. (I could be wrong, please correct me if so). A high resolution CCD device would simply be not necessary.
 
you make some good points, but EVERYBODY:I'M NOT TALKING ABOUT RESOLUTION!!!! I have a $200 300K-pixel digicam and the quality of the images it produces are far superior to expensive dv cams I've tried. THIS IS NOT RELATED TO RESOLUTION AT ALL.
 
300k pixel? u mean .3 megapixel? for 200 dollars? i dunno, maybe because video cameras have um about .3megapixel ccd max i'm guessing. since dvd is 740x480~. low res high speed ccd. maybe it captures pictures as interlaced first and then conconstructs an ugly still.. who knows.
 
Lots of things impact the "quality" of an image.

Your 300K pixel digicam may very well have a great picture. It's a combination of lensing, CCD "tweak", CCD sensivity, the channels the video goes through inside the camera, the storage medium, and a host of other things.

Technically, the CCD's in digicams can be and often are the same ones as those found in DV cams. The digicam just uses the video signal as is, while the DV cam pumps that same signal through an A/D. There are so many different factors that make an image quality "good", that it's very difficult to discern on paper why one camera is better than another. On top of that, different people have different opinions on a good image. I can usually spot a DV image because I know what to look for.

I work at a company that does a lot of high-tech imaging, and we have plenty of DV cams that wipe the floor with Digicams, in all respects.
 
The main goal is to keep the data stream of the DV cam at a reasonable level (for previously stated reasons). And there are many factors that contribute to that. I won't mention the obvious "R" word that you hate to hear, but there are others, such as the levels of luminance in the image. The greater the number of luminance levels, the higher the number of bits required to represent those levels. The DV cam is designed to minimize the amount of information for each image. Also, when you press the button on your digicam, the CCD is "flashed" with the image in front of it and then it takes time for the information on the CCD to offload into memory. The DV cam's CCD is presented with a new image 30 times per second and it has to offload that info that much faster. So they are both designed differently and optimized to perform separate tasks.

And going back to the "R" subject, for real-life images the subtle tones that are picked up well in hi-res are not so subtle in low-res. The hi-res image can use more levels to transition than the low-res image can, thus affecting the quality of the image.
 
Thank you, bassx88, for a useful response! and welcome to AT forums!!!

anyway, so are you saying that one of those dv cams for doing still shots with the 1.3 or whatever megapixel ccds will probably have better quality than one in the normal 380k pix range, even though they both record with about 500 lines of res? I've never tried one of those dv cams with the high-res ccd
 
Originally posted by: dpopiz
Thank you, bassx88, for a useful response! and welcome to AT forums!!!

anyway, so are you saying that one of those dv cams for doing still shots with the 1.3 or whatever megapixel ccds will probably have better quality than one in the normal 380k pix range, even though they both record with about 500 lines of res? I've never tried one of those dv cams with the high-res ccd
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a 1mega pixel camera already can capture 1152x864, so they aren't both limited to 500 lines of res. not to mention possibly capturing only in interlace mode which would kinda suck.

and technically if you had a 1.3mpix ccd dv cam it wouldn't record video at 1.3mpix, but the extra res would help for pictures.

 
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