Any interchangeable lens digital non-SLRs?

Discussion in 'Digital Photography' 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

    Seneca Guest

    I agree, sort of. It is true that the all-optical SLR viewfinder gives an
    incomparably better image than the LCD or (at least at the present time)
    electronic viewfinder, and this counts for something.

    Yes. In fact, cameras in the Minolta DiMAGE 7 series do exactly that for
    manual focus.

    That, and the fact that the EVF is just not nearly as clear or sharp as the
    pentaprism (or mirror prism) arrangement.

    I suppose it's because a) lens mounts and the attendant electrical and
    mechanical connections add complication and expense, and b) digital cameras
    are still pretty much in a state of flux designwise and with respect to
    sensor size. So a camera maker is likely to be reluctant to design a line of
    interchangeable lenses for a new camera when that new camera may be
    completely obsoleted in a couple of years or so and the lenses all become
    orphans.

    I agree it would be great if they did, especially for cameras like my DiMAGE
    7i and 7Hi. I'd love to see an interchangeable-lens version of these, with
    ultrawide lenses (as short as, say, 16mm fisheye and/or 14 to 17mm
    rectilinear equivalent) made available. But I suppose Minolta regards such
    lenses as having too little appeal to the general public and too expensive
    to bother designing for digitals at the present time.

    Seneca
     
    Seneca, Jan 8, 2004
    #4
  5. 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
    #5
  6. 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
    #6
  7. 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
    #7
  8. 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
    #8
  9. 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
    #9
  10. G Huang

    Paolo Pizzi Guest

    Too cumbersome. I wouldn't like it.

    I guess the main reason why Canon/Nikon maintain the pentaprism
    is that the typical customer of their DSLR's is someone who has
    been using a film SLR for a while and he/she would like to transition
    to digital in the most painless way.
     
    Paolo Pizzi, Jan 8, 2004
    #10
  11. G Huang

    JPS Guest

    In message <-labs.com>,
    Marketing rut.
    --
     
    JPS, Jan 8, 2004
    #11
  12. It's most likely a marketing thing.

    The vast majority of the group of photographers that wants interchangeable
    lenses also wants a pentaprism/pentamirror viewfinder, not an EVF. The
    group of photographers that are happy with an EVF are also probably not
    looking to drop hundreds and thousands more $ on additional lenses - a
    one-size fits all, permanently-mounted lens is right up their alley.

    I'm guessing people like you that want an EVF and interchangeable lenses are
    too small a minority to create a new class of digital cameras. If that nice
    market were big enough, somebody would go after it - I don't see technology
    being the stumbling block, but rather, economics. I mean... how many point
    and shoots have interchangeable lenses?

    - jz
     
    Jeff Zawrotny, Jan 8, 2004
    #12
  13. 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
    #13
  14. 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
    #14
  15. 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
    #15
  16. 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
    #16
  17. 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
    #17
  18. 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
    #18
  19. G Huang

    Paul Rubin Guest

    To make a mirrorless SLR body, you'd need a suitably large CCD or CMOS
    Well, first of all, with no mirror it wouldn't be an SLR.

    Second, the objection wasn't as much to the mirror itself, but to
    the moving reflex mirror. However, there are SLR cameras with fixed
    mirrors, like the EOS-1RS, or for that matter the Olympus E-10/E-20.

    Finally, live preview can be provided on a conventional DSLR, by
    having a separate CCD in the viewfinder path. Nikon offers a remote
    viewfinder (tiny video camera that clips onto an SLR eyepiece) for its
    film SLR's and I guess that can work with a DSLR. Movie cameras with
    video taps work something like that too.
     
    Paul Rubin, Jan 9, 2004
    #19
  20. G Huang

    leo Guest

    I don't see any technical reason why not, but the mirror mechanism itself
    doesn't cost much - The film Rebel is in the mid-$200 and the digital Rebel
    is only $300-$400 more than a comparable 6MP P&S.

    As for why no interchangeable lens for small digital cameras, there are
    simply no standard sensor and body size. There are still lots of improvement
    to be done on the sensor and its size.
     
    leo, Jan 9, 2004
    #20
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