Chief Ray Angle and Field of View

  • Thread starter Frank-95
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Maybe try contacting OmniVision and asking them about it.
I'm going to try, although I was already ignored once.

Usually you can just assume that the sensor is placed at the focal plane of the system and the chief ray gives the image height at the focal plane (and thus the sensor). If you want to get into more details with regard to lenslets and how they affect things then I can't help you, as that is well beyond my knowledge level at the moment. About the best info I could find was from page 8 on this pdf: http://www.onsemi.com/pub/Collateral/NOIP1SN025KA-D.PDF
Thank you for the link :)
 
Usually you can just assume that the sensor is placed at the focal plane of the system and the chief ray gives the image height at the focal plane (and thus the sensor). If you want to get into more details with regard to lenslets and how they affect things then I can't help you, as that is well beyond my knowledge level at the moment. About the best info I could find was from page 8 on this pdf: http://www.onsemi.com/pub/Collateral/NOIP1SN025KA-D.PDF
Can anyone please confirm if my understanding is correct: If a manufacturer states that it's sensor has 0 CRA, does this mean that the microlenses at the edges/corners are aligned to their respective photodiodes similarly to those in the center? If a sensor is said to have a non-0 CRA, does this mean that the microlenses/corners are shifted off-center with respect to the photodiodes to achieve this non-0 CRA?

Thanks!
 
Yes, that is correct, @Drakkith. The peak responsivity angle is 0° in the center of the image where the microlenses and pixels are perfectly lined up. And it is increasingly non-zero away from the sensor center to accomodate the rate of increasing CRA of an optical system.

The same CMOS image sensor can even come in different versions, with varying degree of microlens-to-pixel shifts to fit different kind of optics.

For some reason, sensor manufacturers tend to obscure the meaning of these graphs by just writing "CRA (degrees)" on the y-axis, instead of saying what it actually is, namely the peak responsivity angle of the microlens-pixel combination.
 
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