Understanding the ND Filter For Panasonic AG HMC40

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    • #55709

      I'm hoping someone that has a Panasonic AG HMC40 Camcorder can help me understand about the use of an ND filter. I'm  just getting into Pro cams so sorry if my questions seem basic.


      A) Is this correct? ……I have to take out the "inner lens hood" if I want to use the teleconversion lens, but If I just use an ND filter, I  would leave the inner lens hood on and  screw the ND filter to it.


      B)  The manual spec says for ND Filter:  Automatic ON/OFF interlock with IRIS. Can anyone explain this in more detail?


      C) Finally .. Can anyone explain the term MC Protector?



      Thanks for any help regarding these questions


  • #210502

    I can only answer B for you.


    Panasonic has a patented iris/ND filter mechanism that helps to control the amount of light coming into the sensor when the light is very bright.  When an iris is closed down to near pin hole sized, light refracts causing a loss of resolution.  To avoid this, Panasonic has come up with a combination iris/ND filter that keeps the filter out of the way in the normal range of adjustment and flips the filter in front of the opening when the iris is closed down.  This allows the light to be stopped down further without reducing the size of the hole, thus avoiding degredation in resolution that would normally result from refraction at tiny aperature sizes.


     In the normal range of adjustment, it's an iris like any other.  In very bright light, when the iris is closed down, there's an ND filter in there that helps to control the light.  It's automatic, you have no control over it, and no need to control it.


    The HMC 80 also has this.  I believe the other HMC cameras do as well?

    You can view the patent and diagrams at http://www.google.de/patents/US20050238348

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