Digital Rebel 1.6x zoom through viewfinder

Discussion in 'Digital Photography' started by Rob, Jan 6, 2004.

  1. Rob

    Rob Guest

    I know that the CCD sensor size compared to tradional film are
    different which gives all the 'Non-Digital' lens 1.6x more zoom.
    My question is this, when you look through the viewfinder/lens on say
    a 70-300, zoomed out completely (300 x 1.6 = 480) will you see
    entirely what the camera is going to capture at 480 or do you need to
    keep in mind that the TTL view is 300, but the camera is capturing it
    at 480 and keep in mind the difference? Hopefully this makes sence. Is
    the viewfinder going to show me the exact image that the LCD captures
    (related to zoom ratio)
    I have only had the opportunity to play with this camera with the
    included lens, but that one is Canon 'digital' lens and does not have
    this issue.
    Rob, Jan 6, 2004
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  2. SLR means what you see is what you get.

    Best regards,
    Craig Scheiner
    Executive Producer
    CPS Associates
    Video Production and Publication
    Craig Scheiner, Jan 6, 2004
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  3. Rob

    DHB Guest

    "any" 35mm lens including the kit lens is subject to the Field Of
    View (FOV) crop factor which in this case is 1.6x.

    To answer your second question:

    Any SLR camera lets you see through the lens & gives you a view of that
    the film or in this case, what your camera's sensor will see. This brings
    up the Question as to how do they give you an accurate view of what the
    smaller sensor will see?

    The simple answer is that they use a smaller mirror which therefore can
    only reflect the same view as what the sensor will see. Keep in mind that
    "no SLR or DSLR" shows you "exactly" (100%) of the view what will be
    captured on film or sensor. This is because "perfect" optical alignment is
    a practical impossibility. So most SLR & DSLR manufacture's settle for
    about a 94% to 98% view, thus if you see it in the view finder it will also
    be recorded + a little more.

    If you have a Digital Rebel/300D as I do, look at page 133 of the manual
    where it states that the viewfinder only shows 95% of what the sensor
    actually sees.

    Hope this answered your question fully.

    Respectfully, DHB
    DHB, Jan 6, 2004
  4. Rob

    Michael Guest

    Digital SLR's are often built around conventional film houses. But
    conventional cameras are built for 35 mm film, and this includes viewfinder
    optics and mirror/prism geometry. These things will need to be fixed to
    compensate for a smaller digital sensor.

    I assume manufacturers actually do this (anything else would be rather
    silly), but you won't find much information about it.

    So it's a valid question to ask I think.

    Michael, Jan 6, 2004
  5. If you have a Digital Rebel/300D as I do, look at page 133 of the
    ... yet another potential advantage of the non-SLR route....

    David J Taylor, Jan 6, 2004
  6. Rob

    DHB Guest

    David J Taylor,
    as technology races forward there is a constant
    emerging that will eventually dominate the DSLR cameras as well.

    It's called the law of "fewer or no moving parts unusually means greatly
    increased reliability". OK it's probably not a law but I think it's more
    often true & does seem to be where most things are heading.

    Here are just a few items that have been created without moving parts:

    <1> MP3 players.
    <2> Pocket micro voice recorders.
    <3> USB Flash drives to replace floppy & ZIP Drives.

    The list could go on & on but I don't want to get off topic. The point
    is that I think eventually DSLR could be made with almost no moving parts
    including the mirror in the optical path. Some cameras have already done
    this by using a partially reflective mirrored prism that remains in front of
    the senor but both allows enough light to hit the sensor & reflecting enough
    to create a usable image in the viewfinder.

    Won't need to use mirror lock up mode with long telephoto lenses if
    there is no camera shake caused by mirror movement. In time technology will
    overcome all of these problems & we will have cameras with "NO" moving
    parts. Even focusing light can be done with electomagnetics. Can you
    picture a lens without any moving elements to focus? Or how about a lens
    without glass lens elements just a computer controlled group of
    superconducting electomagnetics to focus & zoom as needed?

    Let's just hope, pray & do everything we can to see that we do not
    intentionally or accidentally destroy ourselves before this wondrous day

    Respectfully, DHB
    DHB, Jan 6, 2004
  7. Rob

    Chris Brown Guest

    Assuming you want to take out the shutter too, you're going to have serious
    fun with dust.
    Chris Brown, Jan 7, 2004
  8. Rob

    Mark B. Guest

    The advantage of a dSLR, to me, far outweigh the disadvantages:
    interchangeable lenses, lower noise at all ISOs, faster AF, insignificant
    shutter lag, optical through the lens view (yes, to me this is an
    advantage), better flash systems, etc.

    Mark B., Jan 7, 2004
  9. Rob

    Lew Guest

    You actually get a little more than you see, with the difference being often
    lost in commercial printing. What you see in the viewfinder is about the
    same as what you will see in a print.
    Lew, Jan 7, 2004
  10. For you - this is the case. I am merely suggesting that others should
    take all factors into account when evaluating.

    David J Taylor, Jan 7, 2004
  11. The list could go on & on but I don't want to get off topic. The
    ... in fact I see the ability to adjust lenses by e.g. twist for zoom as an

    David J Taylor, Jan 7, 2004
  12. Rob

    fruitbat Guest

    The D-Rebel is CMOS, but go on...
    Any lens actually, including the kit lens.
    Just FYI, the longer focal length is generally known as zoomed in, not
    The camera isn't "capturing it at 480", exactly. Focal length is focal
    length. I won't go into detail here, though.
    CMOS, but go on...
    The viewfinder provides ~95% coverage of the sensor's field of view.
    The focal length is irrelevant, as is whether the lens is made for a
    digital camera or not. Think of it like this: The lens projects an
    image onto the sensor, and the viewfinder displays 95% of what the
    sensor sees. So WYSIWYG, practically.

    fruitbat, Jan 7, 2004
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