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What happened to CCD sensor technology ?

Discussion in 'Micro 4/3 News and Rumors' started by Bhupinder2002, May 31, 2014.

  1. Bhupinder2002

    Bhupinder2002 Mu-43 Hall of Famer

    Hi guys ..
    I few days go I was playing with and old Nikon D50 and I remembered these cameras used CCD sensor . I also remembered that all DSLRs were using CCD during those days and CMOS sensor was considered inferior . Enter 2014 and I can't see CCD anywhere at all . Does anybody have any idea why manufacturers dumped CCD technology ?
    Thanks
    Bhupinder
     
  2. Lodos

    Lodos Mu-43 Regular

    while I do not have much of information what sensors used in what cameras, I can speculate over some past experience with imaging sensors we have used in our lab for experiments requiring highly sensitive microscopic imaging..

    it is about how technology evolves..

    Normally ccd sensors have more light capture dedicated space per pixel on the sensor compared to the CMOS sensors. In CMOS sensors each pixel hosts some circuitry occupying some more space stolen from active area for light capturing.

    CMOS sensors are usually cheaper to manufacture, and use less power, while they had always higher noise.. that is possibly why some DSLR's in the past used CCD sensors.. similarly state of the art camera equipment used in microscopes or telescopes have also mostly CCD sensors..

    For instance Andor's CCD's given below have quantum efficiencies (QE) approaching above 90% ie they convert each photon to a signal. Pretty good.. but expensive (~30K in US dollars)
    http://www.andor.com/learning-academy/ccd-spectral-response-(qe)-defining-the-qe-of-a-ccd

    Recently (possibly mostly thanks to the consumers), while CCD technology is also advancing, CMOS sensors started to close the gap.. sensitivity and low iso improvements are quite nice.. possibly that is why in the last few years CMOS sensors are inreasingly used in high end DSLR's.

    State of the art CMOS sensors used in scientific equipment are reaching QE's of %70 (possibly around $20k ?).
    https://www.hamamatsu.com/us/en/community/life_science_camera/product/search/C11440-22CU/index.html
    While sounds low compared to 90%, it is still high.. plus these cmos sensors are quite fast that they can get imaging at 100 fps rate at good resolution.. you need SSD's in raid to get the stream of data produced in few minutes..

    In comparison, in Canon 5D Mark II, QE is around %20-30 per pixel If I remember correctly.. Consider each pixel is capturing one color after color filter, you need to divide this number by 3 etc..

    Anyway in short.. cmos sensors are closing the gap in noise and sensitivity while keeping their advantages at cost, power consumption and speed.

    CCDs will be there, needed, but for more specialized applications justifying high cost.

    There is also some difference related to how they capture the light in the sensor area which has some implication over photography (for instance the image skew one may get during panasonic electronic shutter at slow speeds) but that parts are easy to find online such as

    http://www.bhphotovideo.com/c/find/newsLetter/Comparing-Image-Sensors.jsp
     
  3. Cani

    Cani New to Mu-43

    8
    Jan 1, 2014
    I read somewhere the shift to CMOS was also due to the convergence between photo and video (unsure why though... :rolleyes:)