Thread: the problem presentation.

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  1. #1 the problem presentation. 
    Member Yoji Nishimura's Avatar
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    dear all,

    RED ONE have optical filter between CMOS and lens mount.
    It was fault optical design, it's two reason:

    1) not mutch Focal Scale of any lens.
    2) circuit design vs optical dimmer for R-G-B good noise balance.

    could you feel it ? but it's in my opinion..

    -yoji
    - PEN -
     

  2. #2  
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    Quote Originally Posted by Yoji Nishimura View Post
    dear all,

    RED ONE have optical filter between CMOS and lens mount.
    It was fault optical design, it's two reason:

    1) not mutch Focal Scale of any lens.
    2) circuit design vs optical dimmer for R-G-B good noise balance.

    could you feel it ? but it's in my opinion..

    -yoji
    Forgive me if I misread your comments but:

    1) There has to be an optical filter to avoid excessive aliasing. As long as it's an optical flat and a fixed distance from the sensor, and the lens mount back focus is correctly set, then there should not be issues with incorrect Focal Scales on lenses. In fact just used some Cooke S4s which were fine.

    2) The optical filter does not, as far as I know, affect RGB noise balance - it's an inherent physical property of silicon sensors that they are less sensitive in the blue end of the spectrum, and hence relatively more noisy in the blues.
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  3. #3  
    Member Yoji Nishimura's Avatar
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    Quote Originally Posted by ericyoung View Post
    Forgive me if I misread your comments but:

    1) There has to be an optical filter to avoid excessive aliasing. As long as it's an optical flat and a fixed distance from the sensor, and the lens mount back focus is correctly set, then there should not be issues with incorrect Focal Scales on lenses. In fact just used some Cooke S4s which were fine.

    2) The optical filter does not, as far as I know, affect RGB noise balance - it's an inherent physical property of silicon sensors that they are less sensitive in the blue end of the spectrum, and hence relatively more noisy in the blues.
    Thank you for this comments. I will write the below.

    1) Cookes S4 is nice sound :) I added glass filter between Lens and Redone then I got this problem. so Floating optical filter is not good design. to my mind. it's spread heat drift too.

    2) my nikon's D40 have RED Channel noise very much. Redone have BLUE Channel. It's difference of architecture. the characteristic is deep question for us.. I have not this answer.

    I will meditation..

    -yoji
    - PEN -
     

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