Luminous Landscapes on T-Stops

Discussion in 'Open Discussion' started by Djarum, Oct 29, 2010.

  1. Djarum

    Djarum Super Moderator

    Dec 15, 2009
    Huntsville, AL, USA
    Jason
    Luminous Landscapes have generated an open letter here:

    An Open Letter To The Major Camera Manufacturers

    Basically, the author is discussing the issues with sensors and sensor design in relation to fast lenses. What is really being discussed here is pixel/microlens issues. Basically, the faster the lens, the greater the angles of light rays hitting them. Depending on the sensor/pixel design, some cannot handle the extreme angles and the pixel doesn't register all the available light.

    The author's beef is that camera manufactures know this and "secretly" boost ISO a little to compensate. This is a different issue than I really wish to talk about. We might have opinions one way or another on this.

    I think a more elegant explaination is made by Andy Westlake from dpreview:


    http://forums.dpreview.com/forums/read.asp?forum=1018&message=36768003

    He made some calculations using a Noctilux on a GF-1. As you can see from his results, the full aperature isn't fully used.

    I think this is something the legacy lens users might want to know.
     
  2. Rider

    Rider Mu-43 Regular

    139
    Oct 14, 2010
    I can see this affecting the amount of light, but does it also affect the DOF?? Will have to look into some more.
     
  3. Djarum

    Djarum Super Moderator

    Dec 15, 2009
    Huntsville, AL, USA
    Jason
    Yes, it will. The larger the aperature, the larger the blur spot. If the pixels can't pick up the rays, the blur spot won't be as big.
     
  4. Rider

    Rider Mu-43 Regular

    139
    Oct 14, 2010
    But a neutral density filter doesn't decrease the blur, which is why it's puzzling. Will have to read up on it.
     
  5. Djarum

    Djarum Super Moderator

    Dec 15, 2009
    Huntsville, AL, USA
    Jason
    I'm confused by your reference of the ND filter?
     
  6. feppe

    feppe Mu-43 Regular

    It's a purely academic discussion, as we're talking about well less than a stop difference, which is adjusted by the camera in the background with no intervention from the user necessary. No one will be able to tell the difference in the final product (screen or print) in 99.9% of real-life shooting cases, except perhaps very high ISO shots.
     
  7. Djarum

    Djarum Super Moderator

    Dec 15, 2009
    Huntsville, AL, USA
    Jason
    I agree.

    But, its important to note that buying a f.95 lens may only result in something like f1.1.