What do megapixels mean on a camcorder?

[Ickle Yoda1]

I have never had a camcorder before and was looking at buying the Sony SR10E, it says it has 4 Megapixels. I assume this only relates to when it is taking still pics? Does the megapixel count at all when using it for video?

Also, is this the best High Def camera in this price bracket? I need it to have a Hard drive and will mainly be using it for holidays, I would not really be using it for still photo's.

Thanks

[chrishull3]

Originally Posted by Ickle Yoda1

I have never had a camcorder before and was looking at buying the Sony SR10E, it says it has 4 Megapixels. I assume this only relates to when it is taking still pics? Does the megapixel count at all when using it for video?

Also, is this the best High Def camera in this price bracket? I need it to have a Hard drive and will mainly be using it for holidays, I would not really be using it for still photo's.

Thanks

Megapixels only refer to still pictures,as to the sr 10 it is a good cam in the price range if you can live without a viewfinder.

[A n d r e w]

It's the video pixel count that matters. Some cameras have fewer pixels on the sensor than the camera produces, meaning that video resolution is interpolated. Whether that matters or not is another question. Packing millions of pixels onto a small sensor reduces the sensor's low light sensitivity. So it's a matter of balancing sensor size & pixel count with picture quality in a range of lighting situations.

[senu]

Originally Posted by Ickle Yoda1

I have never had a camcorder before and was looking at buying the Sony SR10E, it says it has 4 Megapixels. I assume this only relates to when it is taking still pics? Does the megapixel count at all when using it for video?

Video pixel size is fixed, therefore putting on more Photosites (pixels) than needed may not always make for better video
When pixels are quoted, there is the total pixel count and effective pixel count, which is important
The size of individual Pixels ( photo sites) is such that larger ones will be better at gathering visual information. Smaller ( less efficient) ones will need to be boosted electronically.. this leads to noise and artefacts
Therefore if you have the same size of sensor , having fewer pixels which are bigger and better at light gathering makes for better video
So Bigger sensor, less pixels- great video ( as long as the minimum no for video resoluiton is present)
Conversely Same sensor , more pixels is not as great
Small sensor , many pixels: low light video will struggle
For HD 2.5 Mp is more than enough for video

Also, is this the best High Def camera in this price bracket? I need it to have a Hard drive and will mainly be using it for holidays, I would not really be using it for still photo's.

If you cant afford the SR11/12, the 10 is fine but there is no "best" as such as the real world differences are not startling

[Orwella]

The most important factor for HD recording is generally sensor. a 1/3rd Inch sensor with 2.5M pixels would theoretically be superior to 1/3rd sensor with 5M pxels because each of the larger pixels would be able to accept more light.

Some of the Panasonic's have less pixel count than the 2M required for true HD (1920x1080). This puts them at a disadvantage from the offset.

[A n d r e w]

Originally Posted by Orwella

Some of the Panasonics have less pixel count than the 2M required for true HD (1920x1080). This puts them at a disadvantage from the offset.

It arguably puts them at a disadvantage. The H.264 implementation in AVCHD uses 4:0:0 chroma sub-sampling, so even if you have "enough" pixels on the chip, each chip pixel isn't represented individually in colour terms in the 1920x1080 output picture. Only the luminance levels are sampled for every pixel. Also bear in mind that you're mostly dealing with interlaced video, made up of two fields of 1920x540 (=just over 1 megapixel).

[senu]

Essentially, larger sensor+ enough( but not surplus to need) pixels= Great video!

To the OP what the above posts are trying to do is qualify my simplistic statements

The way that video is such that with formats like DV AVI the video can be likened to jpeg images captured many times over and turned into video
This would require each photo site ("Pixel") involved in the captured and resolved video to be individually sampled. as such if the no sampled is less than the resolution , it would have to be extrapolated. this for SD is often never the case as SD is less than 1Mp
For HD this has to be about 2Mp
In reality, mpeg2 and H.264 are !intraframe " codecs" which use variable parts of sampled image to build up the video, and may not require all pixels to be sampled all the time
It can get complicated
The simple answer to your query is that absolute megapixel nos matters far less with video, than for stills , and even then bigger sensors in each case make the mose difference to quality. It is perhaps technological advancement that we are getting decent video these days from smaller sensors due to improvement in sensor technology and image processing ect