All digital cameras use interpolation

Discussion in 'Digital Photography' started by Charles Schuler, Jan 22, 2004.

  1. Yes they are.
     
    George Preddy, Feb 7, 2004
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  2. Charles Schuler

    Azzz1588 Guest

    No they are not
















    "Only a Gentleman can insult me, and a true Gentleman never will..."
     
    Azzz1588, Feb 7, 2004
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  3. In Message-ID: <bvn621$2eb$> you stated that "You have
    to use the same lens and the same sensor" hence I repeatedly asked you
    what you were comparing carefully stating that using the same sensor and
    the same lens proves nothing, now eventually you decide that you need to
    change the sensor.
    Since "zoom" is a change in focal length which can be expressed as a
    ratio your comment about using it in a resolution test is ludicrous.
    Zoom is something used occasionally in cinematography and rarely in
    still photography, altering the focal length during an exposure to
    determine the resolution of a sensor would make resolution unmeasurable.
    Not that your phrase "3X the optical zoom" makes any sense since '3x' is
    a specific ratio and 'optical zoom' is valueless property you are saying
    '3x something' where the something is unspecified, i.e. it might be 1.5,
    or 5, or 20, or any other value. Still you are attempting to prove Canon
    users wrong by claiming they say things they do not, this is know as
    black propaganda and does your case no credit at all.

    I would conduct resolution tests of sensors by using lenses which have a
    focal length normal to the sensor and with an aerial resolution at least
    four times that of the sensor. In each case I would adjust the distance
    from camera to test chart such that the chart occupies the full width of
    the sensor. I would not alter the illumination. I would use the aperture
    that gives the best resolution, any consequent variation in exposure
    duration will not effect the resolution measurements. You could conduct
    the tests by taking the photographs at a constant distance and using a
    zoom lens which is adjusted to bring the chart to the full width of the
    sensor in all cases; it is of course important that the zoom lenses have
    an aerial resolution of at least four times the resolution of the sensor
    at the required focal length.

    I find it telling that in the test published at
    http://www.outbackphoto.com/artofraw/raw_05/essay.html the image from
    the Canon 1Ds had to be magnified by 1.74 and then cropped by 0.56% to
    make its resolution as bad as the sigma SD9. This is using deception to
    support an insupportable position, another form of propaganda.

    I also find it interesting in the report on
    http://www.outbackphoto.com/artofraw/raw_05/essay.html that the SD9 is
    reported as producing excessive blue, this might explain your "blue
    moon" artefact.
     
    Ian Robert Walker, Feb 8, 2004
  4. Obviously that was a typo, should be "on." Unless you seriously think you
    can switch sensors into different cameras, which it seems you do.
    Obviously you shouldn't change zoom between cameras, that is my point and
    seems to be yours too.
     
    George Preddy, Feb 8, 2004
  5. Yet another unfounded assumption by your self, not that changing sensors
    is impossible as you seem to think, it does require more engineering
    skills than you posses; and would not provide any useful information.

    I am unclear where in "You have to use the same lens and the same
    sensor" you wish to substitute the word "on", if it is for "and" so as
    to give "You have to use the same lens on the same sensor" it has not
    changed the meaning of the sentence and is still meaningless since you
    are not comparing things. Once again I must ask WHAT ARE YOU COMPARING?
    Yet another meaningless statement from yourself, "zoom" is either a verb
    for changing the focal length of a variable focal length lens or as an
    adjective it is a type of variable focal length. You can zoom (the focal
    length of the lens), but you can not "change zoom", you can change a
    zoom lens (adjective). If you read all my comments I allow using
    different focal lengths when using a zoom lens in order to maintain the
    image at the full width of the sensor.

    Once again I must ask WHAT ARE YOU COMPARING?

    I note that you do not dispute this.

    Once again I must ask WHAT ARE YOU COMPARING?

    I note that you do not dispute this.

    Once again I must ask WHAT ARE YOU COMPARING?

    I note that you do not dispute this.

    Once again I must ask WHAT ARE YOU COMPARING?
     
    Ian Robert Walker, Feb 8, 2004
  6.  
    George Preddy, Feb 9, 2004
  7. Right, changing out the sensor in your DSLR is a breeze.
     
    George Preddy, Feb 9, 2004
  8. ....
    ....

    Unless I totally misunderstand you, this is exactly the problem with the comparison
    tests you prefer. You are comparing the SD-9, with all 3.4MP used to display the
    target, against a competing camera with only a portion of its MPs used to display
    the same target. To compare the resolution of each *camera*, each picture needs
    to use the full sensor of its respective camera.

    As a silly example, I could demonstrate the "superiority" of my Minolta S404 over
    your SD-9 by taking a picture with my Minolta that fills the sensor, and taking a
    picture with your SD-9 where the target only fills a quarter of the sensor. Clearly
    my S404 would show more detail than your SD-9. Get it?


    --
    Dan (Woj...) dmaster (at) lucent (dot) com

    "They took all the trees, and put em in a tree museum
    And they charged the people a dollar and a half to see them
    No, no, no / Don't it always seem to go
    That you don't know what you got 'til it's gone
    They paved paradise, and put up a parking lot."
     
    Dan Wojciechowski, Feb 9, 2004
  9. That's not a problem, that's what you get. If you want full frame FOV (and
    many pay in the $4,000 to $8,000 range for that), you get very low
    resolution. Yes, you can concentrate the sensors onto the same FOV by using
    a stronger zoom, but then you no longer have the benefits of a full frame
    camera. Or go the other way, dillute the SD9's 10.3M sensors with a wider
    lens to lower the resolution in exchange for the same FOV. Simple. The
    test is perfect (http://www.outbackphoto.com/artofraw/raw_05/essay.html).

    The 10D of course cannot be saved because it is a cropoing already, and a
    very low res cropper at that with only 6M sensors.
    No. You aren't knowledgable enough about this. DSLR croppers crop from the
    exact same 35mm lens projection. Obviously if you put a tiny little 8MP
    Sony F828 sensor in the middle of a 35mm lens projection, it is going to
    resolve line pairs that no DSLR could imagine resolving--but the FOV will be
    a soda straw, so it is futile.
     
    George Preddy, Feb 9, 2004
  10. Perhaps you did not understand the phrase "it does require more
    engineering skills than you posses", they are an electronic components,
    undoubtedly different resolution sensors will have different pin-outs.
    If there are no processing components on the board carrying the sensor
    then the problems are reduced. It is still not a "breeze", but then I
    never said or implied that it was; nor did I say or assume that you had
    meant that.

    My question remains, WHAT IS IT YOU ARE COMPARING?
     
    Ian Robert Walker, Feb 9, 2004
  11. My complete post excised.

    I am at a loss as to why you quote everything but add nothing; that is
    to say it is the quoting everything that puzzles not the adding nothing
    since despite my repeatedly asking you what you are comparing you have
    failed to answer.


    My question remains, WHAT IS IT YOU ARE COMPARING?
     
    Ian Robert Walker, Feb 9, 2004
  12. Charles Schuler

    Peter Guest

    Why do they *love* the trees so?


     
    Peter, Feb 9, 2004
  13. And that's exactly why comparing the SD9 and 1Ds with the same lens and
    same subject distance is also stupid. If you need the field of view of
    the 1Ds with that particular lens, the SD9 is useless. If you only need
    the FOV of the SD9, then you're wasting most of the pixels of the 1Ds.
    Either way, it's not a fair comparison.

    That's why sane photographers decide what field of view they want to
    capture, then pick an lens FL and subject distance combination that
    captures that field, no matter what the sensor size. And that's why
    resolution test instructions tell you to fill the image width or height
    with a certain distance on the test chart. If you want to remove any
    effects due to two different lenses, you can still match FOV using the
    same lens using different subject distances. That's how it's supposed
    to be done.

    Dave
     
    Dave Martindale, Feb 10, 2004
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