MP sensors for videos

S

-Sandro-

Well-known member
Does it cost more to make a DSLR with 18MP-24MP APS-C sensor that shoots pics and not THAT very good videos (with a powerful CPU to downscale the video) or a "simple" videocamera with the same sensor size but around 3MP that doesn't need to do who knows what to downscale the original video?

I'm asking because it doesn't make sense to me why companies tries to create videocameras for thousands of dollars that the average user can't afford but created 24MP sensor cameras that "everyone" can afford. Isn't it better to sell millions of $700 products instead of thousands of $5000 cameras?

So why no company thought of creating a cheap small factor camera with a 3MP sensor for videos only instead of creating for example the Sony FS100?
 
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there are some sensor manufacturing experts in these forums who can give you a better answer, but I'll pitch in for now...

I think it is actually more difficult to build that 24mpix sensor and the downscaling processor; it can actually lead to better images in some aspects (sharper, without more noise after downscaling) but it's probably going to be worse in others (dynamic range may be smaller)

so, why do they use those high megapixel sensors?

my guess: because they can share the development costs with the photography division, which sells many more cameras (albeit at a much smaller price)
 
In a way, you answered your own question; It's better to sell lots of cheap cameras than very few expensive ones. And if they have to create a whole new sensor just for a video camera, then that camera will be expensive in order to cover the R & D costs. So they won't sell very many.

As Norman said, it comes down to sharing development costs. It is easier and cheaper to make one chip and put it in four different cameras than to make four different chips.

It is also as much a matter of what is shared as it is what is not shared - If Canon were able to use the resources their video department already has (which they can't because they are seperately controlled companies) then the current DSLR's might have much better video perfromance than they do, even using the same 18mp sensors.

The next generation of DSLR's from Canon will most likely have a new Digic V processor with better video scaling and processing. They will share that processor between all the cameras in their line to save R & D costs (same as they're doing with CMOS sensors at the moment), and you'll see significantly better perfromance across the range.
 
Sensor chips are _extremely_ expensive to make in small quantities, the one-off 8x10 sensor (basically stitched from many others) recently reported, costed $500,000-.

APS-C sensors, on the other hand, can run only a few hundred dollars in quantity. If they can find a good financial reason build these sensors in the 100's of 1000's, then yes, you can get them cheaper.

There is actually one company currently making aps-c sized sensors that are nearly perfect for 1080p, but they don't even have video enable tho. That would be the Foveon sensor from Sigma.
 
Well, the sensor in the Sony FS100 and F3 is, according to some Sony information, is 3.36 'effective' megapixels.

by having such a lower resolution, the photosites on the sensor are larger and thus more light sensitive. This is one of the large reasons that theses cameras have such good low-light performance.
 
Sandro, you may be interested in the Apertus camera project, which I think has been mentioned on the forum before:


http://cinema.elphel.com


This is a community-driven free software open hardware modular HD camera project, based on Elphel industrial cameras. The current camera (353) uses a 1/2.5" 5 mgp sensor, though you could shoot 24 fps CinemaScope at a respectable frame size of 2592 x 1120 in good quality mjpeg. However, the project is still in development so for folks who just want to buy a camera and start shooting straight away, it would be best to wait for the work to continue some. The next up-coming camera model (373) should have a bigger sensor (possibly APS-C size) which might be of more interest to you.

I used to follow this project on DVinfo a while back, so it's good to know the work continues on their own website which also has a forum.
 
all the industry is flawed by the same state of mind. why bother to design something when you can just tweak some old stuff , put a new name on it and sell millions of them.
even iPhone is in the same wagon. Since consumer mind and advertising is oriented to "more is better", you can just expect sensor to get higher pixel count, then dual sensor,
then multi processor driven etc... Quality is not supposed to be increased (hi8 was better than DV, CD is better than mp3, CCD was better than CMOS) but at least deliver the same
service level.
In the same time, the industry is removing all what really cost (mechanics, hard to produce parts) to keep only things that can be build at large scale for nothing.
So goes the car industry, where almost all models share the same design and lots of them are even the same model or chassi+motor, revamped under several names.
All in one , there is some benefits on long term, but it could go a lot faster.
This is not always the fault of the industry. Consumer prefer cheap DVD instead paying the price tag for Bluray, just because the perceived added value is not great enough.
Even in this forum, the cheapest lens maker (tokina, sigma) are often preffered over expensive Canon ones, just because they reasonably "do the work" for the price, even if
the quality and performance of the expensive lens is fully recognized.

so yes, you want the best, the only problem is you do not want to spend the money to get it..
 
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