Any interchangeable lens digital non-SLRs?

Discussion in 'Digital Cameras' started by G Huang, Jan 8, 2004.

  1. G Huang

    G Huang Guest

    A traditional SLR gives a convenient way of previewing what's being
    captured through the lens. A digital camera can do this previewing
    electronically through the LCD screen. It seems that the
    penta-prism/mirror mechanism is an unnecessary complication, at least
    for some photographers. Ok, the full frame LCD does not have enough
    resolution to allow precision manual focus, but a special zoom mode can
    be added to display the actual pixels of the center area to facilitate
    focusing with a press of a button. For those insisting on eye-level
    viewfinder, a small LCD with an eyepiece can be added to make an
    electronic penta-prism. The only drawback I see is the slight increase
    in battery consumption because of the constant use of LCD.

    So, the obvious question is, for mass production cameras, why only DSLRs
    are designed to have interchageable lenses?

    GH.
     
    G Huang, Jan 8, 2004
    #1
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  2. G Huang

    Dave Cohen Guest

    I've not used the converters available for my and other Canon's, so I can't
    comment on quality of image, but that would seem to be a partial attempt to
    satisfy the need.
    Dave Cohen
     
    Dave Cohen, Jan 8, 2004
    #2
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  3. G Huang

    Bill Guest

    None that I know of. My Fuji S602Z has an electronic viewfinder
    (EVF)......which I use most of the time to compose my shots. And even with
    that (or the LCD) in use, battery usage has not been a problem. While it
    might be nice to be able to change the lens (like an SLR), I do have a wide
    angle adapter that does a nice job! I haven't needed a telephoto adapter,
    since the 6X optical zoom serves my needs well.

    I think the reason that manufacturer's don't make interchangeable lens
    cameras is that they would have to make a new standard for these lenses. The
    market probably doesn't justify it. It's easier and cheaper for them to
    develop a camera that uses existing lenses. So they have done that with
    digital SLR's.

    Bill
     
    Bill, Jan 8, 2004
    #3
  4. G Huang

    G Huang Guest

    I don't see the need for new line of interchangeable lenses. There are
    plenty of lenses already. Why can't there be a mirrorless Rebel using
    Canon EF lenses, or mirrorless Dimage using Maxxum lenses?
     
    G Huang, Jan 8, 2004
    #4
  5. G Huang

    G. Huang Guest

    My OP was not why there are no new lens mount. I don't see the need for
    new lens mount at all. My point was that they (Canon, Nikon) can design
    a digital camera without the mirror mechanism and still use their
    favorite (EF, AF-Nikkor) interchangeable lenses. These mirrorless and
    shutterless bodies will probably be cheaper to make since there are no
    moving parts.
     
    G. Huang, Jan 8, 2004
    #5
  6. G Huang

    Bill Guest

    Because those lenses will not focus properly on the smaller CCD's found in
    most digital cameras. Therefore, the manufacturer's had to design the
    digital SLRs using larger sensors, that can work with all the lenses that
    are already abundant. That's why in my reply I stated that the investment in
    a new type of lens (one that WILL work with the CCD's used in most digital
    cameras) would probably not be worthwhile to the camera makers. This was
    also similar to what Seneca posted in the previous reply.

    Bill
     
    Bill, Jan 8, 2004
    #6
  7. G Huang

    bob Guest

    They could put optics in the space normally occupied by the mirror, to
    reduce the image circle to match the smaller sensor.

    Bob
     
    bob, Jan 8, 2004
    #7
  8. G Huang

    G. Huang Guest

    That maybe true, but I still don't see fundamentally why larger sensors
    (same size as in SLRs) cannot be used without the mirror. Is this an
    electronics issue?
    GH.
     
    G. Huang, Jan 8, 2004
    #8
  9. G Huang

    JPS Guest

    In message <-labs.com>,
    Marketing rut.
    --
     
    JPS, Jan 8, 2004
    #9
  10. It'd be nice, wouldn't it? They could even take the same lenses -- no
    contstraints on back-focus distances and such, so it could be designed
    for about any lens mount.

    There is, however, one reason -- the CCDs that are designed to produce
    continuous video readout (needed to drive an LCD viewfinder) aren't as
    good as ones that just capture a single image. The circuitry to do
    the resolution reduction and continuous readout takes up -- shock
    horror! -- space on the chip. So this hypothetical camera wouldn't
    give as good pixels as the SLR version, probably showing up mostly as
    higher noise.
     
    David Dyer-Bennet, Jan 8, 2004
    #10
  11. Why would they require a new standard? They could perfectly well make
    it take Nikon lenses, or Canon EF lenses, or any of a number of other
    existing standards.
     
    David Dyer-Bennet, Jan 8, 2004
    #11
  12. Optical is higher resolution, but it's often less bright. It's also
    often in an inconvenient location. The only place *I* find the
    resolution a serious drawback is for manual focusing. I mostly avoid
    manual focusing these last 9 years (since I got my first autofocus
    SLR). There are, however, times when it's the best choice still. I
    don't find that so serious a draback compared to improved stealth,
    wider range of shooting positions, and brighter, easier-to-see
    viewfinder.
     
    David Dyer-Bennet, Jan 8, 2004
    #12
  13. The problem is that 35mm SLR lenses are designed to allow room for a
    mirror. That makes the both the lenses and camera body bigger than
    they have to be for a rangefinder type camera. This would negate what
    I see as one of the major benefits of the proposed system.

    There are other lens standards out there, of course, but I can't think
    of any of them that include autofocus or automatic exposure through
    aperture adjustment. I don't know how much of a market there is for a
    manual focus "digital rangefinder" camera, but it suppose Leica or
    Voightlander could produce such a thing.

    Hmmm. The 4/3" sensor used by Olympus is just about the same size as
    a 110 negative, right? Perhaps Pentax could introduce a digital
    camera which uses Pentax 110 SLR lenses!
     
    Michael Benveniste, Jan 9, 2004
    #13
  14. G Huang

    Bill Guest

    Those lenses won't work with the small CCD's found in most non-SLR digital
    cameras. So the choices for manufacturers were to either design new lenses
    (as I said not economically practical), or design cameras with larger CCD or
    CMOS chips that could use "traditional" lenses. The second choice was much
    better, and made for good marketing strategy.

    Bill
     
    Bill, Jan 9, 2004
    #14
  15. You're actually talking about two different things here.

    To make a mirrorless SLR body, you'd need a suitably large CCD or CMOS
    sensor that provides live video preview output. Apparently none of the
    existing SLR sensors does this, but it could be done in principle
    (possibly at some sacrifice in performance). You'd also need an
    electronic viewfinder good enough to focus with. Once you're done,
    you'd basically end up with something that operates like many of the
    current P&S digicams, but with interchangeable lenses.

    However, this mirrorless camera would still have a shutter. The sensors
    in P&S digicams seem to operate in two different modes. In preview
    mode, they provide video output updated many times a second. But for
    taking a single high-quality image, they still need a mechanical
    shutter. The exposure sequence goes something like this:

    - Press shutter release halfway. Camera autofocuses wide open.

    - Aperture stops down, light meter reading is taken

    - Shutter closes entirely. CCD is swept clean of charge in the dark

    - Shutter opens, holds for exposure time, closes again

    - Image data is read out of the CCD in the dark

    - Shutter reopens for preview mode again.

    Just look into the lens of a digicam taking an image. You can see the
    shutter and aperture (sometimes they're the same mechanism) moving.

    A shutterless body would require completely electronic shuttering. For
    whatever reason, it's mostly video cameras that can do this, not still
    digital cameras. I don't know what additional CCD structures are
    required.

    Dave
     
    Dave Martindale, Jan 9, 2004
    #15
  16. G Huang

    Chris Brown Guest

    No moving parts, and a shedload of dust coating the sensor.
     
    Chris Brown, Jan 9, 2004
    #16
  17. G Huang

    Bill Guest

    Technically, you may be right. But at the time the concept of the SLR was
    introduced, the only technology available was mechanical optics (mirrors,
    lenses and prisms). Now the same effect can be achieved with an LCD in the
    viewfinder......i.e. an EVF. The net result is about the same, as far as
    seeing what the main lens is seeing, for composition. DOF preview is a
    little harder to emulate, and in any case it has to be a good quality
    display to be comparable. So if a dSLR had an EVF instead of a mirror and
    prism.....it would essentially be the same thing.

    But my fixed-lens camera has an EVF and I have no problem at all using it
    all the time. In fact, it was one of the main features that I wanted when I
    went shopping for my second digital camera. I was used to shooting with my
    Canon SLR film camera. I do a lot of macro shots, and I hated having to
    compose macros with the LCD when using my first digital camera. Nearly
    impossible in bright light!

    It seems that now, digital technology has made a new type of camera
    available....... sort of a hybrid. A camera that lets you view through the
    lens, like an SLR, but one that has a fixed lens. Personally, I like it. One
    reason I didn't buy a digital SLR..........laziness! I just don't want to
    lug all that stuff around with me anymore!
    Lenses......bellows......extenders.....
    And I get the bonus of making a movie now and then if I want to.

    Bill
     
    Bill, Jan 9, 2004
    #17
  18. But we're talking about trying to get DSLR quality levels, aren't we?
    So I was assuming comparable sensor sizes, since that's one of the
    most basic quality determinants.
     
    David Dyer-Bennet, Jan 9, 2004
    #18
  19. But you'd still be viewing through the taking lens, which is the
    important point.
     
    David Dyer-Bennet, Jan 9, 2004
    #19
  20. G Huang

    AA Bob Guest

    There's more to a DSLR than interchangeable lenses. Metering and focusing
    is done off the imager using special optics and circuitry - hence we have
    prisms and mirrors. That's why DSLR are so much faster than non-SLR type.
     
    AA Bob, Jan 9, 2004
    #20
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