Camera mechanisms

Archived from groups: alt.comp.periphs.dcameras (More info?)

It seems that everyone knew just how a film camera worked with drawing,
sketches, et al. BUT just how does a digital SLR camera such as a Sony
DSC-F828 work? What happens when you change from a photosize of 8 megs to 5
megs, or 3 to 2 ratio or e-mail ratio? Does the area on the CCDs change or
are selected CCD's turned off? How can it change ISO speeds? Does it still
have a mirror and pentaprism? The books that I have read do not get into
this kind of detail. They seem to just talk about the basics of picture
taking.
8 answers Last reply
More about camera mechanisms
  1. Archived from groups: alt.comp.periphs.dcameras (More info?)

    "Ed Mullikin" <edmull2@cox.net> wrote in message
    news:XWOSc.27559$Jo1.8961@lakeread01...
    > It seems that everyone knew just how a film camera worked with drawing,
    > sketches, et al. BUT just how does a digital SLR camera such as a Sony
    > DSC-F828 work? What happens when you change from a photosize of 8 megs to
    5
    > megs, or 3 to 2 ratio or e-mail ratio? Does the area on the CCDs change
    or
    > are selected CCD's turned off? How can it change ISO speeds? Does it
    still
    > have a mirror and pentaprism? The books that I have read do not get into
    > this kind of detail. They seem to just talk about the basics of picture
    > taking.
    >
    >
    The change in picture size and resolution is all done in software or
    actually firmware in the case of a digital camera. The software works much
    the same as a photo editor (Photoshop) manipulates digital images on your
    computer.

    A 5 megapixel camera always takes a 5 megapixel image from the ccd.
    Software then down samples to make a lower resolution image.

    That is why a one megapixel image taken with a 2-5 megapixel camera always
    looks better than the same image taken with a one megapixel camera.

    --
    CSM1
    http://www.carlmcmillan.com
    --
  2. Archived from groups: alt.comp.periphs.dcameras (More info?)

    "CSM1" <nomoremail@nomail.com> wrote in message
    news:4wPSc.5674$57.332@newssvr23.news.prodigy.com...
    > "Ed Mullikin" <edmull2@cox.net> wrote in message
    > news:XWOSc.27559$Jo1.8961@lakeread01...
    > > It seems that everyone knew just how a film camera worked with drawing,
    > > sketches, et al. BUT just how does a digital SLR camera such as a Sony
    > > DSC-F828 work? What happens when you change from a photosize of 8 megs
    to
    > 5
    > > megs, or 3 to 2 ratio or e-mail ratio? Does the area on the CCDs change
    > or
    > > are selected CCD's turned off? How can it change ISO speeds? Does it
    > still
    > > have a mirror and pentaprism? The books that I have read do not get
    into
    > > this kind of detail. They seem to just talk about the basics of picture
    > > taking.
    > >
    > >
    > The change in picture size and resolution is all done in software or
    > actually firmware in the case of a digital camera. The software works much
    > the same as a photo editor (Photoshop) manipulates digital images on your
    > computer.
    >
    > A 5 megapixel camera always takes a 5 megapixel image from the ccd.
    > Software then down samples to make a lower resolution image.
    >
    > That is why a one megapixel image taken with a 2-5 megapixel camera always
    > looks better than the same image taken with a one megapixel camera.
    >
    > --
    > CSM1
    > http://www.carlmcmillan.com
    > --
    >
    I did not answer your question about ISO.

    The sensitivity, or gain of the ccd is changed to reflect the desired
    sensitivity to light. When you use higher ISO the noise is more noticeable
    because the gain is turned up higher on the ccd.

    --
    CSM1
    http://www.carlmcmillan.com
    --
  3. Archived from groups: alt.comp.periphs.dcameras (More info?)

    On Thu, 12 Aug 2004 19:55:02 GMT, "CSM1" <nomoremail@nomail.com> found these
    unused words floating about:

    >"CSM1" <nomoremail@nomail.com> wrote in message
    >news:4wPSc.5674$57.332@newssvr23.news.prodigy.com...
    >> "Ed Mullikin" <edmull2@cox.net> wrote in message
    >> news:XWOSc.27559$Jo1.8961@lakeread01...
    >> > It seems that everyone knew just how a film camera worked with drawing,
    >> > sketches, et al. BUT just how does a digital SLR camera such as a Sony
    >> > DSC-F828 work? What happens when you change from a photosize of 8 megs
    >to
    >> 5
    >> > megs, or 3 to 2 ratio or e-mail ratio? Does the area on the CCDs change
    >> or
    >> > are selected CCD's turned off? How can it change ISO speeds? Does it
    >> still
    >> > have a mirror and pentaprism? The books that I have read do not get
    >into
    >> > this kind of detail. They seem to just talk about the basics of picture
    >> > taking.
    >> >
    >> >
    >> The change in picture size and resolution is all done in software or
    >> actually firmware in the case of a digital camera. The software works much
    >> the same as a photo editor (Photoshop) manipulates digital images on your
    >> computer.
    >>
    >> A 5 megapixel camera always takes a 5 megapixel image from the ccd.
    >> Software then down samples to make a lower resolution image.
    >>
    >> That is why a one megapixel image taken with a 2-5 megapixel camera always
    >> looks better than the same image taken with a one megapixel camera.
    >>
    >> --
    >> CSM1
    >> http://www.carlmcmillan.com
    >> --
    >>
    >I did not answer your question about ISO.
    >
    >The sensitivity, or gain of the ccd is changed to reflect the desired
    >sensitivity to light. When you use higher ISO the noise is more noticeable
    >because the gain is turned up higher on the ccd.
    >
    >--
    >CSM1
    >http://www.carlmcmillan.com

    "Technically" <G> the gain is turned up on the processing circuitry that
    reads the CCD as it converts the cell charge (analogue) to a digital format
    via amplification and A2D conversion.
  4. Archived from groups: alt.comp.periphs.dcameras (More info?)

    Thank you! I would therefore assume that there is no such thing as an f
    stop either. My SLR would however have a pentaprism that still has to get
    up out of the way of the light entering camera and striking the CCd's, would
    it not?

    "CSM1" <nomoremail@nomail.com> wrote in message
    news:qWPSc.5677$8d.4441@newssvr23.news.prodigy.com...
    > "CSM1" <nomoremail@nomail.com> wrote in message
    > news:4wPSc.5674$57.332@newssvr23.news.prodigy.com...
    > > "Ed Mullikin" <edmull2@cox.net> wrote in message
    > > news:XWOSc.27559$Jo1.8961@lakeread01...
    > > > It seems that everyone knew just how a film camera worked with
    drawing,
    > > > sketches, et al. BUT just how does a digital SLR camera such as a
    Sony
    > > > DSC-F828 work? What happens when you change from a photosize of 8
    megs
    > to
    > > 5
    > > > megs, or 3 to 2 ratio or e-mail ratio? Does the area on the CCDs
    change
    > > or
    > > > are selected CCD's turned off? How can it change ISO speeds? Does it
    > > still
    > > > have a mirror and pentaprism? The books that I have read do not get
    > into
    > > > this kind of detail. They seem to just talk about the basics of
    picture
    > > > taking.
    > > >
    > > >
    > > The change in picture size and resolution is all done in software or
    > > actually firmware in the case of a digital camera. The software works
    much
    > > the same as a photo editor (Photoshop) manipulates digital images on
    your
    > > computer.
    > >
    > > A 5 megapixel camera always takes a 5 megapixel image from the ccd.
    > > Software then down samples to make a lower resolution image.
    > >
    > > That is why a one megapixel image taken with a 2-5 megapixel camera
    always
    > > looks better than the same image taken with a one megapixel camera.
    > >
    > > --
    > > CSM1
    > > http://www.carlmcmillan.com
    > > --
    > >
    > I did not answer your question about ISO.
    >
    > The sensitivity, or gain of the ccd is changed to reflect the desired
    > sensitivity to light. When you use higher ISO the noise is more noticeable
    > because the gain is turned up higher on the ccd.
    >
    > --
    > CSM1
    > http://www.carlmcmillan.com
    > --
    >
  5. Archived from groups: alt.comp.periphs.dcameras (More info?)

    "Ed Mullikin" <edmull2@cox.net> wrote in message
    news:mbSSc.27701$Jo1.13664@lakeread01...
    > Thank you! I would therefore assume that there is no such thing as an f
    > stop either.

    Absolutely there is, in any camera... or more specifically, in any
    multi-element lens such as is used with a camera. "F-stop" is merely a
    ratio between the focal length of the lens (f) and the diameter of the
    minimum opening the light goes through, which on lenses with adjustable
    apertures, is typically controlled by an iris-type aperture. On cheaper
    cameras it's simply a fixed opening: if a fixed lens is rated f/4, it means
    that the smallest opening in the light path of the lens has a diameter 1/4
    the focal length of the lens. For a lens with a 60mm focal length, the
    aperture would be 60/4, or 15mm diameter.

    > My SLR would however have a pentaprism that still has to get
    > up out of the way of the light entering camera and striking the CCd's,
    would
    > it not?

    Your digital SLR works exactly the same as your film SLR, except that an
    optical sensor (CCD, CMOS, etc.) is placed behind the shutter where the film
    frame would normally sit. You push the button, the mirror flips up, the
    shutter opens for the set amount of time allowing the sensor or film to be
    exposed to the light, then the shutter closes and the mirror flips back
    down. There may be minor design differences, like a small viewfinder area
    to compensate for the sensor being smaller than a film frame, but
    functionally, they work on the same time-honored principles.

    I believe you'll find most "compact" digital cameras are the functional
    equivalent of their "point-and-shoot" film cousins as well.
  6. Archived from groups: alt.comp.periphs.dcameras (More info?)

    Matt Ion wrote:

    > Your digital SLR works exactly the same as your film SLR, except that an
    > optical sensor (CCD, CMOS, etc.) is placed behind the shutter where the film
    > frame would normally sit. You push the button, the mirror flips up, the
    > shutter opens for the set amount of time allowing the sensor or film to be
    > exposed to the light,

    I haven't been looking in this segment of the market, but don't some of
    the digital "SLR's" skip the mirror/prism and just put an LCD monitor in
    the viewfinder?


    > I believe you'll find most "compact" digital cameras are the functional
    > equivalent of their "point-and-shoot" film cousins as well.

    There are basic differences once you get beyond the most basic (ie
    no-focus) models:

    Focus: Film P&S typically focus with an infrared beam rangefinder. If
    you take a picture through a window is will generally focus on the glass
    instead of your subject. Digital cameras focus to maximize edge
    sharpness of the TTL (through the lens) image. Many cameras can steer
    the focus zone off the center spot either manually or depending on where
    the camera thinks your subject is.

    Exposure: Film P&S uses spot or center weighted average. Digitals,
    having access to the TTL image, often have matrix, multispot, etc modes
    similar to high end SLR's (but generally minus the manual modes).
  7. Archived from groups: alt.comp.periphs.dcameras (More info?)

    > I haven't been looking in this segment of the market, but don't some of
    > the digital "SLR's" skip the mirror/prism and just put an LCD monitor in
    > the viewfinder?

    If it's a true DSLR, then no, it still has the mirror/prism, and the image
    you see in the viewfinder is through the lens, just like it is on a film
    SLR.
    "SLR-Like" digitals have a Electronic View Finder (EVF), and in those you
    *are* looking at a screen.
    Cameras such as the Fuji S602 and Sony 828 have an EVF and are therefore not
    SLRs.
  8. Archived from groups: alt.comp.periphs.dcameras (More info?)

    >BUT just how does a digital SLR camera such as a Sony DSC-F828 work?

    The Sony 828 is NOT an SLR because it doesn't have a Single Lens Reflex
    mechanism. (IE mirror and prism to allow you to view through the lens in the
    viewfinder)
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