Best old Pentax fixed lens for K100?

Discussion in 'Pentax' started by D.M. Procida, May 21, 2007.

  1. D.M. Procida

    D.M. Procida Guest

    The new Pentax lenses seem to cost a fortune (relative to what I can
    justfy spending) so I'd like to go the cheap route and buy an old lens

    What I want is a 50mm-equivalent, nice and bright, and obviously the
    more compatible with things like the camera's autofocus the better. One
    thing I don't want to have to do is deal with something that the camera
    can't meter with properly.

    What would you suggest? There are so many lenses out there on the
    second-hand market that I have no idea what might be worthwhile and what
    might be a waste of time and money.

    D.M. Procida, May 21, 2007
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  2. D.M. Procida

    Karl Winkler Guest

    Here are a few possibilities:

    31mm f/1.8 - giving you approximately the equivalent of a 45mm lens on
    a 35mm SLR
    35mm f/2 - giving approximately the equivalent of a 52mm lens on a
    35mm SLR camera.

    This web site has listings of just about everything:

    Karl Winkler
    Karl Winkler, May 21, 2007
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  3. D.M. Procida

    Matt Clara Guest

    Here's a reply to a question about the best Pentax for the money also
    considering out-of-focus effects (bokeh). I can't find the original thread
    on google groups, but I saved this to my harddrive it was so complete.
    Thanks to Peter Boorman for the post (aka Bandicoot). Peter wasn't
    considering crop factor, and he gives more info than you probably require,
    but there's a ton of information from an experienced photographer who uses
    Pentax almost exclusively (other than medium format needs):

    "Hmmm, best bokeh and sharp for these FLs. Well, I haven't used all of the
    options/versions for all of these FLs, but from what I have used, here's my

    Perhaps before I go on I should make sure you know what the K, A, etc.
    appellations mean. These are all K-mount bayonet lenses that I'm
    describing, in chronological order. You could, alternatively, use the older
    screw-mount lenses and still get much of the benefit of the optics, but
    these days I think the price differential used is so small that I'd probably
    only consider the bayonet lenses and bodies (of course, if you get a really
    good price on a screw-mount lens, you can still use it on a K-mount body
    with an adapter, though you'll have to use stop-down metering.)

    K - earliest version, metal, manual focus

    M - optimised for compactness. Some use the same optical formula as their K
    predecessors, some don't. Not all the lenses that exist in K (or A)
    versions were also made as M versions. Metal bodied. Manual focus.

    A - first lenses that support shutter priority and programme operation (it's
    manual or aperture priority only with earlier lenses). Some of these are K
    or M designs with the 'A' feature added, others are new designs. Several K
    and M designs were 'tweaked' a little for the A versions. Metal bodied.
    Manual focus.

    F - first lenses with AF. A few changes from the A optical designs, but
    mostly the same designs. Some plastic, some metal.

    FA - later AF lenses, the main changes are that more information is
    exchanged between the body and the lens, on bodies that support it (KAF2
    mount bodies). Some changes from F optical designs in some lenses. Some
    plastic, some metal.

    FAJ - designed for bodies that can set the aperture, no aperture ring on the
    lens itself. An abomination. Plastic.

    Then there are some lenses for the reduced sensor size digital bodies, and
    some digitally optimised lenses that cover the full frame size.

    Also, there are the Limited lenses: these have AF and can be compared to
    luxury versions of the FA type: no holds barred optical designs and very
    nice mechanicals.

    And finally the * lenses - eg. A*, FA*, etc. Originally this was those that
    used ED glass types, and essentially now it is an indication of a somewhat
    higher quality level, though * lenses don't exist for all FLs, since this
    design isn't always necessary. They have nice metal barrels (usually) and
    for the AF ones there's a very nice AF/MF clutch mechanism that means that
    the focus feel in manual is much better than is usual for an AF lens.

    All these lenses have Pentax's SMC coating, but the coating has 'evolved'
    over time, and in particular the A and later lenses seem slightly more flare
    resistant than the earlier lenses - though the Ks are still more flare
    resistant than a brand new Canon lens, so who's complaining? >;-) The
    Limiteds have Pentax's "Ghostless" coating, which is a sort of
    super-super-multicoating (this and their very good coma is one of the
    reasons I find them particularly good for night shooting).

    OK, so to specifics:

    28mm - the f3.5K is, I think, the sharpest, and has nice bokeh. The f2.8s
    may be just behind the 3.5s for sharpness, but are at least their equal for
    bokeh - and from f4 or 5.6 are indistinguishable on sharpness anyway. Of
    the f2.8s, I think the A is the best version I've used, but the FA is said
    to be its equal or perhaps slightly better.

    The 30mm f2.8K is probably sharper and with (even) better bokeh than any of
    these 28s, but hard to find (no, mine isn't for sale!) The 31mm f1.8 FA AL
    Limited is sharper still, with nice bokeh and excellent coma, though for
    bokeh per se, the 30mm is at least as good and probably my preference - I
    need to do more testing really to tell apart these two lenses both of which
    I like a lot.

    35mm - the f2 supposedly has the best bokeh. I have an f2M and it is nice,
    but I wouldn't say it's necessarily any better than the f3.5K I have, which
    I think is the sharpest. The f2A may be better, but I've never used one.

    50mm - well, of course here you are spoilt for choice. None of the Pentax
    50s is anything less than excellent, and even the ludicrously cheap f2 will
    blow the doors off the much touted f1.8s of some other makers we won't
    mention. However, everyone seems to agree that the best is the f1.4A, and I
    must agree that mine is indeed a very special lens. The f1.2A possibly has
    even better bokeh, and wide open a rather special look, but it is not as
    sharp as the f1.4 until about f5.6, at which point I can't tell them apart
    (though some people claim that they can). The f1.7M is very nearly the
    equal of the 1.4A, and will cost you a lot less. The f2.8 A and FA macros
    are also incredibly sharp - maybe the sharpest 50s you'll ever find - and
    their bokeh is not all that different to the other 50s.

    85mm - the f1.4s are said to have the best bokeh, with the A* being the best
    for distance work (landscapes) and the FA* more optimised for portraits. I
    don't have either of those however. The f2 has a bad reputation in some
    parts, though I know people who have it and like it - maybe it's good, just
    not as good as the other 85s. The one I have is the f1.8K, and it is an
    excellent lens, very compact and with attractive bokeh, good for people and
    for landscape. The f2.8F Soft-Focus is also really nice, and if you enjoy
    portraits may be worth a look. Don't overlook the 77mm f1.8 FA Limited
    either, which may be the sharpest of all of these.

    You've skipped the 105mm f2.8K which is a real cracker, and the 120mm f2.8M
    which I think is a very undervalued lens these days. Also the 100mm
    macros - all are good but the absolute star is the 100mm f2.8 FA Macro: you
    won't find a sharper lens, and its bokeh is very good indeed: better than
    other macros I've known (some have awful bokeh) and certainly as good as the
    much touted 90mm Tamron.

    135mm - the 'star' has to be the f1.8A* ED, which is one of my favourites
    and a great people lens. But it is very heavy and has become expensive.
    Nearly as good, very nearly as sharp and with similar bokeh, but lighter and
    cheaper is the f2.5K (not the much cheaper Takumar which is a different
    design, cheaper, and not SMC coated). The f2.8 FA IF is very nearly as nice
    as the f2.5K if you want AF (though it is a very ugly lens to look at, looks
    like the army designed it.) The f3.5 in all its versions is very cheap to
    buy, very small and compact, and a good lens by anyone's standards, just not
    quite up there with its f1.8 and f2.5 cousins. The 150mm f3.5K is good
    too - I like it more than the f3.5 135mm, and it is actually lighter than
    the 135mm f2.5K.

    200mm - the f4 macros have good reputations but I've never used one. The
    other f4s tend not be well thought of: they are not really bad lenses, but
    they don't quite reach the standard compared to other Pentax mid-long
    primes. The 200mm that I prefer is the f2.8 FA* ED IF - this is remarkably
    sharp and contrasty for a 200, and the bokeh is good. Once you get beyond
    about 135mm, bokeh often tends to become harsher with anyone's lenses, and
    this 200 has bokeh _at least_ as good as anything else I've seen of this

    300mm - the f4K/M/A is a good lens, but I prefer a little more contrast.
    This you get, along with sharpness and, for a 300, good bokeh, with the f4A*
    and f4M*. This (mine is the A* version) is my preferred 300 for
    hand-holding and/or if bokeh is a key concern. The f4.5F* ED IF is probably
    a tiny bit sharper and is the lens I prefer for tripod use (or if I want AF,
    of course) but I think the A* has slightly nicer bokeh. The FA* is the same
    optical design as the F*, but lacks the F*'s tripod mount, for some reason.

    Phew - hope that's some use. I didn't mention zooms since none really has
    bokeh quite as nice as a fixed FL, and I'm writing enough as it is!"
    Matt Clara, May 22, 2007
  4. For your requirements the best non-budget-busters would be a Pentax-A or
    -F 28mm F/2.8 which meter perfectly, though the -A model is manual focus.
    Equal to 42mm on digital. Double your ISO and F/2.8 becomes as fast as
    F/2.0 :^)

    Even with manual focus, when shooting outdoors you won't have to focus
    very often.

    Don't be afraid to try a similar non-Pentax lens if the price is very
    low... besides the very fine Pentax-A 28mm I own a Vivitar A-mount 28mm
    which is 95% as good. From the UK I got a cheap Miranda 24mm F/2.8 (36mm
    equivalent) which is decent enough, though not spectacular.

    On your K100 going wide costs more than going long, since there are tons
    of used telelenses available at very low prices.
    Charles Gillen, May 22, 2007
  5. D.M. Procida

    Paul Mitchum Guest

    You want this web site to compare Pentax and Takumar K-mount lenses:

    Your camera can meter just fine with any manual lens, as long as you
    understand the limitations: <>

    You can also troll around for M42 screwmount lenses, which you can use
    on your camera body with an adaptor.
    Paul Mitchum, May 22, 2007
  6. D.M. Procida

    D.M. Procida Guest

    That's going to be noticeably wider though, than a closer 50mm
    equivalent, isn't it?

    D.M. Procida, May 22, 2007
  7. D.M. Procida

    D.M. Procida Guest

    Thanks for the excellent and helpful responses.

    D.M. Procida, May 22, 2007
  8. D.M. Procida

    John Bean Guest

    But very close to the "ideal" 35mm standard of 43mm.

    Incidentally the Sigma 30/1.4 probably meets your needs
    quite well :)
    John Bean, May 22, 2007
  9. Among the fairly numerous and relatively inexpensive OLDER Pentax lenses,
    you have little choice. A 35mm film lens becomes 52.5mm on the Pentax,
    so it is safer to start at 28mm and get 42mm, which many folks think is a
    far better "normal" focal length, so much so that Pentax even sells the
    42mm "pancake" lens for its film cameras. On film 50mm has always felt a
    bit too narrow for me, so the 28mm acting like 42mm on digital better
    matches what your eye sees.

    Don't be afraid of cheap manual focus lenses. Look around eBay... you
    can add a 50mm F/2.0 or the better F/1.7 quite inexpensively... they are
    great portrait lenses.

    Anyhow, autofocus with "fast" lenses isn't as reliable as one would hope,
    since the autofocus sensor doesn't really look at the focus screen... but
    your eye does. I have an expensive autofocus Pentax F/1.4 which is not
    at all reliable at portrait distances. Autofocus seems more accurate
    with lenses of F/3.5 or slower.
    Charles Gillen, May 22, 2007
  10. Too true, but in the USA it costs $400... for that much money on eBay a
    first-time Pentax K100 owner could buy quite a selection of used lenses
    and thus learn what she next wants, when the budget permits. Meantime,
    the 18~55mm kit lens is a useful bargain that should not be forgotten.

    When I went digital Pentax, I confess to having overbought on eBay,
    winding up with multiple 50mm primes and 70~200mm zooms, but the
    learning curve was instructive. For persons on a tight budget, a "good
    enough" lens in the hand is worth a dozen one lusts for but can't afford.
    Thanks to digital processing, even a no-name optical "dog" can usually be
    enhanced enough to justify its low cost until one can afford better.

    Good luck, Daniele :^)
    Charles Gillen, May 23, 2007
  11. One mustn't forget the stunning portraits that can be captured
    with a 50/1.4 or 50/1.7. These are classic lenses that don't cost
    too much and yet have stunning bokehs. eBay's prices for these
    manual focus lenses have started to drop, so you might be able to
    get a bargain.
    Mr Ashraf Saleh, May 23, 2007
  12. D.M. Procida

    John Bean Guest

    Although it's not obvious you have to remember that the AF
    system is "seeing" the wide-open image and trying to assess
    maximum edge contrast, so it's not how bright a lens is but
    how sharp/contrasy it is *wide open* that determines how
    well the AF will work.

    The Pentax 50/1.4 is a lovely lens at f/2.8 and beyond, but
    it's wide open performance is pretty dismal so no surprises
    that it's AF is not as reliable as a slower but sharper

    Same applies to zoom lenses, probably even more so because
    many are both slow and have poor sharpness wide-open - worst
    of both worlds.
    John Bean, May 23, 2007
  13. D.M. Procida

    jeremy Guest

    35 years ago, I employed that same argument to add cheap wide angle and
    telephoto lenses to my arsenal. I immediately noticed just how bad their
    results were, in comparison to my SMC Takumar normal lens.

    I still have those "Lentar," "Samigon" and "Mark IV" lenses, but I haven't
    shot with them in over three decades.

    I've since acquired 19 more SMC Takumar prime lenses (this over a period of
    33 years), and I have come to the conclusion that I'd rather have only one
    excellent lens, rather than a bag full of junk.

    The cost of making photos is the same, regardless of whether one uses
    excellent equipment and technique or uses mediocre equipment and poor
    jeremy, May 23, 2007
  14. D.M. Procida

    jeremy Guest

    They were a bargain even when they were new, because they were mass-produced
    and often the manufacturers took a loss on them, as they were their flagship

    Asahi Pentax is purported to have sold every one of their 50mm f/1.4 SMC
    Takumars at a loss, because they were competing with Zeiss and they wanted
    to show off their quality to as many buyers as possible.

    I am a big fan of normal lenses. I have 7 of them. Their natural
    perspective, fast speed and excellent descriptive power make them my
    favorite of all focal lengths.
    jeremy, May 23, 2007
  15. D.M. Procida

    D.M. Procida Guest

    A follow-up question - from further reading I understand that the K100
    has a version of the K mount which can't read aperture settings from
    certain lenses; it can only do so from lenses with an A-setting - is
    this correct?

    So for example, would this lens's aperture be readable (when set by the
    aperture ring) and controllable (when the camera is in auto-exposure
    mode) by the camera:


    D.M. Procida, May 23, 2007
  16. D.M. Procida

    John Bean Guest

    Yes. The "crippled" KAF2 mount used in some of the later
    film bodies.
    If the lens aperture ring is not set to "A" then it becomes
    unknown and can be used only in manual mode with stop-down
    metering, as can any non-A lens.
    John Bean, May 23, 2007
  17. D.M. Procida

    Paul Mitchum Guest

    Yes and no. The camera can't figure out the aperture setting from the
    ring on the lens, but that doesn't make the lens useless with the
    camera. You just have to do manual stop-down metering. So switch to
    'M'anual mode and then press 'ae-lock' to meter the scene.

    Here's an article I wrote about it. I wrote it for the *ist DS, but it
    should still apply to the K100/K10 series:
    That lens is an A-series lens, so you'd want to set the aperture ring to
    the 'A' setting. Then the camera can do all the automatic stuff you
    want, except auto-focus.
    Paul Mitchum, May 23, 2007
  18. Daniele, you are on the right track. An A-mount lens will do everything
    you want except autofocus. The older K or PK lenses can also be used
    easily, but with them you have to first adjust the aperture manually on
    the lens, then push a button on the camera so it can set the appropriate
    shutter speed.

    NOTE: if this will be your first lens-buying experience on eBay, be aware
    that for desirable lenses, the bidding may rise sharply in the final few
    minutes... and very often the lens is won by a "sniper" who made no
    previous bids at all but waits until the last few seconds. Good luck, but
    do not become addicted to eBay :^)
    Charles Gillen, May 24, 2007
  19. D.M. Procida

    Han Schutten Guest

    A small warning: I use several older prime lensen on a Pentax K10d (no
    A-mount). The metering is not always accurate. If you change the aperture
    setting, the indicated shutter speed doesn't change accordingly sometimes
    (e.g., change aperture from 5.6 to 8, indicated shutter speed changes from
    1/125 to 1/30 instead of 1/60). I therefore always make a test shot and
    check the histogram. Nothing for the hurried photographer, no problem in
    cases where the scene permits this way of acting.
    The A-mount lenses behave as described in various posts.
    Han Schutten, May 24, 2007
  20. D.M. Procida

    John Bean Guest

    You're right, the K10D has a "bright" screen that causes
    metering problems with non-A lenses.

    However the query here was about the K100D which has no such
    issue, and if you wish you can swap your K10D screen for one
    from the *istD/DS to cure the metering problem with non-A
    lenses on the K10D too.
    John Bean, May 24, 2007
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