Telephoto lens choice for Sony A100?

Discussion in 'Sony' started by Pete Kendrick, Sep 17, 2006.

  1. I'm looking to buy a telephoto for my Sony Alpha 100 which I've just bought
    (first DSLR so this is all new to me).

    Should I go with the Sony AF 75-300mm or the Sigma 70-300mm which I think is
    also available?

    Or is there a better choices at around the same price?


    Pete Kendrick, Sep 17, 2006
    1. Advertisements

  2. Pete Kendrick

    Alan Browne Guest

    I had the Minolta 75-300 (and the Sony is optically the same, I
    believe). It was sharp and contrasty through about 200mm, after that a
    bit on the soft side.

    Sold it long ago.

    As all this is new to you, be advised that the rule of thumb for sharp
    zooms is a zoom ratio not greater than about 2.5:1. The lens you're
    considering is 4:1.

    Consider 2 lenses rather than 1.

    Alan Browne, Sep 17, 2006
    1. Advertisements

  3. Thanks for the advice. I'm not quite sure what you mean by the zoom ratio.
    Is there a website which offers an explanation?

    Would the Sony AF 18-200mm be a better (and more expensive) option? And
    would it make my current lens (18 - 70mm) redundant?



    Pete Kendrick, Sep 17, 2006
  4. Pete Kendrick

    bmoag Guest

    If you are new to SLR photography you will get more use and enjoyment out of
    the 18-200 then you will out of lugging around a second lens in the 70-200
    range when you want to have telephoto capability.
    Unless you buy top end glass there is not a lot to distinguish the lenses
    from different manufacturers in the middle of the price range.
    I do not know about the Sony 18-200, which I presume is a new lens for that
    I have used a variety of the 18-200 lenses out there for dSLRs and for
    general use these are very good lenses, much better than the old 28-200
    lenses for 35mm SLRs and equal to or much better than most moderate cost
    70-200 zooms in that focal length range. At the wide end they have more
    barrel distortion (easily correctable in Photoshop) than your kit lens,
    which you should use unless you need the long end of the zoom.
    If you learn how to use Photoshop and do not plan to routinely make16 x20
    inch prints the dirty little truth is that absolute lens quality does not
    mean what it did in a world of film based images that received more or less
    straight printing from a negative or transparency.
    In a digital world where all images receive software sharpening how does one
    know what one is seeing in a print?
    bmoag, Sep 17, 2006
  5. I don't mean to pretend to be Alan Browne, but the zoom ration is
    determined by dividing the smaller number into the larger one. In the
    case of the camera you are considering, 75 divided into 300 goes 4
    times, so the zoom ration is 4 to 1; if you accept the 2.5 to 1 that
    Alan cites as the recommended maximum zoom ratio, multiply the smaller
    number by 2.5, which in this case is 187.5, or very close to 200.

    Note that the Sony 18-200 has a zoom ratio of 10 to 1.

    Noel Stoutenburg, Sep 18, 2006
  6. Pete-

    Zoom ratio is like 18-70 (3.9 to 1) or 18-200 (11.1 to 1). Which is
    better depends on your definition of better.

    A lens with a lower ratio, say 35-70 (2 to 1) may be sharper, if all other
    factors were equal. However 2 to 1 is not much of a zoom. Higher ratios
    require more compromise in lens design, but you may be willing to accept
    that if you need the higher zoom range.

    Early Sony lenses are likely to be identical to existing Minolta designs,
    just re-branded. You might also look for used Minolta Maxxum or Dynax
    lenses. I would expect them to be of higher quality than Sigma,
    especially at higher ratios.

    I have a Minolta 70-210 f/4 lens in my collection that makes a nice
    addition to the 18-70 kit lens. I purchased it used several years ago for
    use with a film camera, and it works well with the Sony Alpha.

    Fred McKenzie, Sep 18, 2006
  7. Pete Kendrick

    BobF Guest

    It all depends on your use... I have the Sony 18-200 which I use as an all
    purpose 'walking around' lens, one advantage is I never have to change lenses so
    I avoid dust... I carry this camera everywhere to take snapshots... If I
    wanted to take more 'serious' photos I would use a prime lens, (no zoom) but I
    have a Nikon to do that with. I have a 24mm F1.8, and a 50mm F1.8. I don't have
    a prime telephoto since I haven't decided on which one yet... but around 200 or
    300 would be good. Tripods are required for a larger lens.

    Ask yourself what you want to shoot, first... and what quality you want.
    BobF, Sep 18, 2006
  8. Pete Kendrick

    Bill Guest

    Avoid dust?

    Hmm...the lense isn't sealed and zooming has a tendency to "pump" air
    in and out. How is that better? And the amount of dust that gets
    inside when changing lenses in an average environment is negligible
    anyway. I'd have to say you're really no further ahead.

    I mean c'mon, look inside your camera and tell me how the dust gets on
    the sensor when the shutter is open only ~0.00001% of the time the
    camera is actually in use? It's not like the sensor is exposed all the

    This "dust scare" being marketed by companies is almost as bad as the
    twits in homeland security saying there's going to be a terrorist
    attact. They don't know where or when or who or how, but as long as
    they say it'll happen, everyone feels much safer being told that they
    don't really know what they say they know.
    What's wrong with zooms?

    I have one here beside me that I would have no issues putting up
    against primes in the same focal range.

    Granted primes are great optically...but I'd rather carry a 70-200
    zoom that will cover a lot more for me than a 100 or 200mm prime that
    is more limited. The very slight difference in optical quality (not
    visible in most cases) is well worth the trade off in convenience.

    Just my opinion though.
    Bill, Sep 18, 2006
  9. Bill wrote:
    Small maximum aperture, sometimes as small as f/5.6, compared to the f/1.8
    prime lenses which BobF mentioned. Makes a considerable difference to
    light capture, ease of focus, ease of viewing, bokeh etc.

    David J Taylor, Sep 18, 2006
  10. Pete Kendrick

    Bill Guest

    And who said we had to use crappy zooms?

    My lenses happen to be f/4, but a friend of mine has mostly f/2.8 zooms,
    and in my experience, the f/1.8 lenses pretty much suck wide open and
    only match the 2.8 versions stopped down, so why bother?

    For the viewfinder brightness, I agree. But most of the rest is hype.

    Nobody in their right mind shoots an f/1.8 or better wide open unless
    they really need the tight DOF or they're working in ultra low light and
    are willing to sacrifice sharpness and distortion to get the shot.

    By the way, I happen to have an f/1.8 50mm.
    Bill, Sep 18, 2006
  11. Thanks for the advice, everyone!!

    I think, perhaps, as suggested by BobF I may go for a general 'walking
    around' lens such as the Sony 18-200mm. And as I'm going to start evening
    classes next week on using Photoshop (fantastic, I'm a student again at
    38!!) I'm sure I'll figure out how to correct any barrel distortion.

    Sometime in the future I'm sure (finance permitting, I've only just bought
    the Sony Alpha and all the relevant gubbins) I'll want to broaden my
    expertise by buying specific lenses for specific jobs.

    Thanks again.


    Pete Kendrick, Sep 18, 2006
  12. Pete Kendrick

    BobF Guest

    Are you kidding?? Not sealed? As in "open camera sitting on a table" ?? Wow
    you're really pushing the shit! How about a 10 second exposure on a telescope?
    Ever seen the dust bunny's that fall out of telescopes?
    I returned the first Nikon I bought because there was already 2 dust spots on
    the sensor, and I wanted a clean new camera. The Nikon I now have, 2 1/2 years
    old, has had lots of dust, which I blow off. There are a few small pieces
    left... one was quite large, not even Adobe would eliminate it.
    So no DSLR sensor's have any dust? Are you retarded?
    They are generally cheap and have poor light gathering ability. To get the same
    F number in a zoom that is found in a $400 prime, you would need to spend maybe
    $5000, which the OP isn't likely to do. Nor I since I haven't yet spent $2k on
    Nikon lenses and have almost all I need.
    apples and oranges...
    sure is...
    BobF, Sep 19, 2006
  13. Quite a few Konica Minolta 75-300mm (D) lenses have been around from
    prices around £49.50 upwards, new, remaindered stock. They may all have
    gone but getting one for around £99 as opposed to the £150+ you are
    likely to pay for the Sony version (very slightly improved in terms of
    feel and probably better quality control overall) would be worth the

    To go with your 18-70mm, this is a good choice. It is light, relatively
    small and really adds fresh tele range with no overlap. It shares the
    same 55m filter thread, for UV or polarisers. Overall peformance is
    surprisingly good for a cheap lens, but it's best to stop down one stop
    - f6.3 to f 8 is a sensible working setting.

    The Sigma - the real question here is 'which Sigma?'. The cheapest Sigma
    is not likely to outperform the Song/Konica Minolta, while the more
    expensive APO labelled version(s) will probably be better. Sony has
    temporarily discontinued the former Minolta/Konica Minolta 100-300mm
    f4.5-5.6 APO (D) lens, which is or was the best possible choice for
    digital bodies - more compact still and very sharp, but twice the price.
    They may be reintroducing it, everyone hopes with a faster focus
    mechanism or even perhaps an ultrasonic focus motor. This is the only
    reason anyone can think of as to why it has been dropped, and only the
    cheap 75-300mm remains in the line-up as a basic tele zoom.

    So my answer would be - if you can afford a Sigma APO variant, get it;
    if not, save your money, find a cheap final stock or used Minolta/KonMin
    75-300mm (D) and survive with that until Sony introduce further lenses -
    or begins to drop the price of the initial models.

    David Kilpatrick, Sep 19, 2006
  14. Thanks again everyone for the advice. I can see this is going to be a useful
    place to visit.


    Pete Kendrick, Sep 19, 2006
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.