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EOS Bodies / Re: Patent: Canon Foveon Sensor
« on: May 24, 2013, 11:39:56 AM »Each pixel of the new Canon prototype sensor can capture all the colors.
This is made possible by the physical fact that long-wave (infrared) light penetrates deeper into Silicon than shortwave blue light.
Red light penetrates most deeply into Silicon, green light penetrates only up to the middle and blue light reaches just below the surface of the Silicon.
With the sensor informations the camera system can calculate, which color the pixel see.
The sensor filter is no rasterized like the Bayer pattern. You don´t need a anti-aliasing filter that blur the image. And you don´t need to sharpen the picture to get an usable image. The full performance of the attached lens is available in the image after taking the picture.
Not quite accurate. "Full performance" is a non-linear factor when it comes to lenses. A high quality lens, such as one of Canon or Nikon's super telephoto lenses, offers maximum resolution at their maximum aperture. With say a 600mm f/4 lens, at f/4, the maximum potential spatial resolution is 173 lp/mm. Currently, no sensor on earth offers comparable spatial resolution. The highest resolution DSLR sensors, Canon's 18mp APS-C and Sony's 24mp APS-C, offer (with the most optimistic measure) 116 lp/mm and 129 lp/mm. Neither of those sensors bring out the "full performance" of any lens, especially not top of the line professional gear.
Why make the new sensor design sense?
You get sharp images, fine details, perfect realistic colors and no moire.
All of these facts, except the "fine details" one, are true. Simple fact of the matter is, with three sensels at every pixel, you have a lot more raw data points to process in any given read than with a bayer type sensor. That affects how fast you can read, which limits how how far you can push spatial resolution with a foveon design. Currently, the fastest DSLR's process at ~500mb/s. A 36.3mp Foveon would need 200mb/s just to read out ONE SINGLE FRAME in a SINGLE SECOND! You DO get full color information at every pixel, but there are bayer sensors capable of resolving nearly as good color information, just as sharply, with FAR more fine detail.
This is one of the fundamental drawbacks of foveon-style sensors. They are sensel dense, but not pixel dense. From a spatial resolution standpoint, foveon is about 2/3rds LESS capable of resolving fine colored detail than a the top bayer sensors (factoring in the spotty spatial resolution of the red and blue channels). From a purely luminance standpoint, Foveon is about half as good or worse than the best bayer sensors.
The argument for Foveon is often made in the form of: "You can always scale Foveon up and get just as good IQ as a bayer". To some degree, this is true...with the exception of the spatial resolution (fine detail) factor. However the inverse is most definitely true: "You can always scale bayer down and get just as good or better IQ than Foveon."
The question is, what you want to shoot. The new sensor is very good, but not good for all. If Canon put the new sensor on the market they have also products with the normal sensor design on the market.
I would agree with this...assuming Canon ever puts the sensor on the market. I think MCS designs will probably ultimately take over in the long run. Increasing SNR will be critical to achieving higher and higher usable ISO settings, and I think any sensor design that relies on the filtration of light will eventually fall in favor of designs that maximize how much light is used, eliminating the need to filter at all.
It´s a little bit like AF-systems. the phase-AF is faster but the contrast-AF has a bigger hitrate. I see that the future of the AF-systems is a combination of both passive AF-systems.
Sorry, but the AF system comparison is no longer true. According to LensRentals, modern Canon equipment (newly released lenses paired with a new body like the 5D III or 1D X) is capable of producing just as high a hit rate with PD-AF as with CD-AF. PD-AF is now just as accurate as contrast methods, but considerably faster. For the types of photography that rely heavily on high speed AF lock and tracking, contrast detection will NEVER be sufficient, even when paired with phase detection. The raw performance of PD-AF with a dedicated sensor will never be surpassed, and I do not see AF-critical photographers ever choosing a camera that combines PD-AF with CD-AF.






