Lens compatability between Digital slr and old Pentax film slr

Discussion in 'Pentax' started by Lee Whitney, Jan 14, 2008.

  1. Lee Whitney

    Lee Whitney Guest

    I currently own aPentax ZX-50 SLR and have had it for over 10 years. As part
    of the kit it came with the Pentax-F 35-80mm lens and I also purchased a
    Tamron AF 100-300mm lens. I am now considering stepping up to a digital SLR
    and I am considering the Pentax K10D and I am wondering if these lens will
    work with the new digital camera. Also will the auto focus feature of the
    K10D work with these lens also, I understand that the Pentax has the
    autofocus built into the camera and not the lens.

    Lee Whitney, Jan 14, 2008
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  2. Yes, both of those lenses will work just fine with the K10D! However, you
    will have to put the aperture setting on "A" and control the aperture from
    the camera, rather than the lens.

    For the gritty details of lens compatibility, search for Bojidar Dmitrov's
    extensive page... however, to make a long story short, all the Pentax
    lenses all compatible with the new DSLRs except that you can't use the
    aperture ring.

    *All* Pentax SLRs (both film and digital) have in-camera focus motors,
    except for one short-lived early 80s model. So autofocus will work just

    I personally use a couple of old lenses (A50 f/1.7, and A70-200 f/4) with
    my new K10D and they both work great. Metering is perfect, and the shake
    reduction works too because it is in-body :) The extensive compatibility
    with old, inexpensive lenses is one of the main reasons I chose Pentax.

    Daniel Lenski, Jan 14, 2008
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  3. Lee Whitney

    Tony Polson Guest

    Pentax is expected to announce a replacement for the K10D at the PMA
    show in Las Vegas, which starts on January 30, 2008. It would be
    worth waiting to see what new DSLRs are announced at PMA before you
    make any major buying decisions.

    DPReview normally offers up-to-date reports on announcements at PMA,
    so watch this space:

    Tony Polson, Jan 14, 2008
  4. Lee Whitney

    OG Guest

    The autofocus is in the usual place, but in its current cameras Pentax has
    "Shake Reduction" built into the body rather than the lens, which means that
    you can still benefit from SR using your existing lenses. Other brands have
    SR in the lens, so old lenses won't give SR.

    As for the rest, yes your lenses will work
    Daniel mentioned that you'll have to set the aperture ring to 'A', this is
    the default setting, but AFAIK it's not essential for the K10D; AIUI you can
    change a setting so that you can operate in full Manual mode. There is a
    button you can press that sets the appropriate shutter speed .

    I've got the K100D rather than the K10D, both are very nice cameras, and
    should be real bargains as the K20D and K200D are introduced.

    Don't forget that the sensor is smaller in the DSLR than in a film camera,
    so your old lenses give the same field of view as a 50% longer focal length,
    A 35mm behaves like a 50mm, and your 100-300mm will be the equivalent of a
    150-450mm telezoom. This sounds good, but it means it will be worth looking
    for a new wide angle lens.
    OG, Jan 15, 2008
  5. Well, the specs on the K20D (its presumed name) are all-but-revealed
    already, since the Samsung GX-20 has been leaked: http://
    www.engadget.com/2008/01/10/samsungs-gx-20-dslr-leaked/ Just as the
    Samsung GX-10 is a clone of the Pentax K10D, the GX-20 is probably a clone
    of the K20D (the two companies collaborate in their design).

    More interesting to me is the likely K200D... it's rumored to have a
    similar body to the K100D Super, but upgrading some features to the K10D
    level: 10 megapixel, 3 fps unlimited JPEG shooting, better autofocus.
    Could be an amazing deal if it keeps the K100D's entry-level price point
    of under $500 for the kit.

    On the other hand, Pentax K10D and K100D Super prices seem to have swung
    markedly upward in the month since I got mine... apparently there's a
    supply shortage right now since they've reduced production of the K10D and
    K100D. Prices may actually go up if there's a long wait until the new
    models actually hit the shelves.

    Of course, all this is speculation, I guess we'll find out in 10 days :)

    Daniel Lenski, Jan 15, 2008
  6. That's a good point, which I'd forgotten. You *can* use the aperture
    rings on older lenses, but then you have to do stop-down metering, which
    is a little slower, unless you're in full manual mode. I've used it
    though, and it works as expected!

    Daniel Lenski, Jan 15, 2008
  7. Lee-

    Isn't the ZX-50 an autofocus SLR? If so, and those lenses are
    autofocus, they should work perfectly with any of the Pentax DSLRs.

    If you have older manual-focus KA lenses, set the aperture ring to the A
    setting. Other than having to manually focus them, they will work
    perfectly otherwise.

    The old K (Non-A) series lenses will work, but it is a little more of a
    bother to use them, as will old screw-mount lenses with an adapter.

    Fred McKenzie, Jan 15, 2008
  8. Lee Whitney

    m II Guest

    Daniel Lenski wrote:

    It's what I do with my old screw mount lenses. The adapter ring lets all
    the 42mm stuff to bolt onto the K type mount. I love the backwards
    compatibility of Pentax bodies.

    m II, Jan 15, 2008
  9. Lee Whitney

    Tony Polson Guest

    Not with "A" lenses.

    Just set the aperture ring to A and you get everything except
    Tony Polson, Jan 15, 2008
  10. Lee Whitney

    RichA Guest

    Price difference between the new one and the k10 is likely to be $600-
    $800. The K10D is probably (next to the $1000 D200 bodies out there
    now) the best value in a DSLR. Too bad about Pentax's poor telephoto
    (near non-existent) offerings.
    RichA, Jan 15, 2008
  11. Lee Whitney

    Pete D Guest

    Mostly shooters don't actually buy big glass anyway so it is rarely a
    problem, thos few that do need the big guns shoot Nikon or Canon anyway but
    pay a huge price for the privilage.
    Pete D, Jan 15, 2008
  12. Lee Whitney

    OG Guest

    I'd probably put that as 'not' using the aperture ring
    OG, Jan 15, 2008
  13. Lee Whitney

    Tony Polson Guest

    OK, agreed.

    Tony Polson, Jan 16, 2008
  14. Lee Whitney

    RichA Guest

    I think Olympus and Pentax miss th boat by no longer/not having 300mm
    f4 lenses for about $1000.00.
    RichA, Jan 16, 2008
  15. Lee Whitney

    Dan Lenski Guest

    Well... there are Sigma options for the Pentax cameras. And Tamron is
    coming out with some more lenses, and Pentax is also supposed to come
    out with their own 300mm prime at some point soon.

    Dan Lenski, Jan 16, 2008
  16. Lee Whitney

    Net Doe Guest

    This is the situation I had, except I had the Pentax ZX-5n, hence
    I bought the K10D, and I love it. The lenses are 100% compatible.
    Keep in mind the 1.5x factor between film and DSLRs.
    Net Doe, Jan 18, 2008
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