Sigma and Minolta A2 (comments)

Discussion in 'Minolta' started by David Kilpatrick, May 19, 2004.

  1. I've just been using these two side by side for a week in Turkey, aiming
    to get a few library pix. Before going I was not happy with either;
    despite having 12-24, 50 macro, 18-50 and 55-200 for the Sigma that
    total range is actually no more effective than the 28-200mm for Minolta,
    for which I also had the two optical converters 0.8x and 1.5x. Yet I had
    doubts about the Minolta optical quality and performance, and the
    Sigma's resolution for the size of final file I have to create.

    End result was that the Minolta got more use despite serious
    difficulties in bright light with the finder, simply because it could
    'go everywhere' and was ready for any shot without changing lenses. My
    best single image, an alpine view with goatherd approaching me in a road
    under pines in backlight, was grabbed very rapidly on the A2 and is
    absolutely perfect though I was almost using the viewfinder 'blind' and
    not even trying to see whether the focus had locked. So were the other
    shots taken, using raw, of the same subject - with no problems over
    buffer emptying.

    By sticking rigidly to using 64 speed, no noise reduction, no anti-shake
    (except on individual pictures needing it), raw format, and various
    other settings - and then by processing using Photoshop CS instead of
    Minolta's own tediously slow software - I got images which were
    genuinely up to 8 megapixel standard when compared to the best 5
    megzpixel files I've had in the past.

    The Sigma files suffered, after the first day of use, from a lot of
    sensor dust - or maybe it's cover glass dust. Anyway, with clear blue
    skies, it was annoying. The colour can not be faulted if you are a
    travel agent, and I imagine the intense hues it has produced will sell
    well. Certainly, the images make the Minolta shots even after a +25
    colour saturation boost all round look muddy and flat. The Sigma pix
    look like slides on a lightbox, and Ektachrome EBX slides at that; the
    skies, in particular, look more intense than polarised blues and don't
    grade much to the horizon. The extremely good distinction between fine
    detail colour/texture changes is amazing in the SD10, but there are also
    some peculiar issues; even at ISO 100, skies which should have been pure
    blue had an underlying pattern of magenta and green noise, yet small
    white clouds ended up 'coloured in' by the surrounding blue.

    The 12-24mm lens, which proved so very sharp on a trip to Paris in
    January, performed really badly. I couldn't believe it was the same
    lens. It's had a few car trips and airline flights, but it was never in
    the hold baggage. It just seems suddenly to have deteriorated and the
    cause seems to be a focusing error. The 18-50mm and 55-200mm, used for
    the first time in really good light and generally stopped down to f8 or
    f11, actually proved very good. I've been using them wide open most of
    the time in Scotland and a bit disappointed, but when stopped down, they
    are both very crisp. The 50mm macro EX I found disappointing on distant
    shots; it really was only showing any quality when used for macro, and
    that meant for about three shots in the entire week.

    I did shoot some stage show shots at 800 ISO and, despite criticisms of
    noise, they were far better than I expected. Those taken at ISO 400 were
    almost impossible to tell from 100 ISO results. By mistake I left the
    camera on 400 and shot half a dozen daylight views on this setting. I
    actually deleted several in-camera, thinking they would be of no use at
    all (I made this same error last year with the Olympus E-1, and the fast
    setting files which resulted were useless). But I had not deleted them
    all, and when I came to process the images, I realised I'd done two or
    three of the 400 shots and not even noticed the difference at 200 per
    cent view. In fact they were perfectly usable.

    Comparind 100+ final selected processed files, the Minolta A2 used with
    the strict parameters I stuck to has more fine image detail and more
    natural colours. The Sigma images have more browser impact; even though
    the Photo Pro 2 software generally 'reduced' colour saturation
    automatically - and not many pix were allowed through on the auto
    setting, which is extreme in terms of adjustments - they all have an
    overstated, extremely sunny-looking, crisp colour. Since my shots were
    all travel market images of an area associated with blue skies and
    waters, and since the Sigma shows ancient Greek ruins as honey-gold
    against intense sky blue, I suspect these will sell better.

    The dirt on sensor issue is a nasty one. The A2 went everywhere - on
    board boats, out and about in high winds (Caria can be very windy as
    well as very sunny), in dust etc. Of course, every image is perfect from
    the sealed camera. The SD10 now needs cleaning.

    Next experiment, I guess, is to try the A2 with TIFF files in camera
    using Vivid Colour sRGB - and maybe the Sigma can find its way to a
    dealer to sell on commission. I'm flat broke and the A2 will do
    everything I want to do. But the Sigma kit will be missed as there are
    some unique aspects to the images it produces, and I won't be entirely
    happy until something comes along which has the same clarity and colour

    David Kilpatrick, May 19, 2004
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  2. David,

    Many thanks for you report - it makes interesting reading. I am glad the
    A2 was of use to you - I could not use it in the manner you described (64
    ASA, RAW) and it seems a pity that the camera is let down by its firmware
    and software. Your comments on dust and speed of reaction confirmed my
    own observations about high-end P&S vs. DSLR.

    I hope your shots sell well!

    David J Taylor, May 19, 2004
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  3. David Kilpatrick

    Lionel Guest

    You might try the experiment of doing a luma only (ie; Lab mode) sharpen
    on one of your Minolta shots, converting back to RGB, then upping the
    saturation. You might find that makes a big difference, & I suspect that
    the Sigma conversion software does something similar by default.

    If you get a chance to try it, I'd be most interested to know whether
    you find it helps.
    Lionel, May 19, 2004
  4. If they sell at all I'll be happy. So far no sales in May, bit
    disappointing, but I see that Alamy has a big (up front) feature in
    Practical Photography this issue, which will encourage a lot more
    photographers to sign up - though they make the process sound daunting,
    with many hurdles to get through. In fact, despite the 'quality control'
    procedure, they have never rejected any of my digital camera images and
    all they have done is query why I chose to have five or six different
    similar images, one Rights Managed and the rest Royalty Free. Easy one
    for me - I am picture editor, and when one image clearly has people in a
    better distribution (simply a better shot) I see no reason why this one
    picture should not be 'expensive' when similar ones with figures less
    attractively disposed in the shot are cheaper.

    I do not see more photographers as competition. I see it as a
    co-operative effort. The more images come up on a search the better,
    unless you get eighteen lightbox pages of crap.

    They argue that a buyer searching will find all the shots, and just go
    for the Royalty Free. My argument is that since other photographers have
    the same subject, and some of those are RF, they are telling me I might
    as well never used Rights Managed terms because the buyer will always go
    for the cheaper shot even if it's not as good. I think that's not the
    case and I've left my 'composition and timing bracketed' shots of a few
    subjects in place. One of my complaints about libraries in the past was
    the cherry-picking from unedited slides. When I use images, I may need
    (for example) a clear space on the left, or extra bleed all round, or a
    large blank area at the bottom for text and overlaid images. So I think
    libraries should offer all six variations on a shot if they have been
    taken, not just pick what looks the tightest/best single image.

    Time will tell!

    David Kilpatrick, May 19, 2004
  5. Tried it, and studied two near-identical shots (taken about 10 seconds
    apart from same viewpoint). It's not down to this. But, using LAB, the
    difference is apparent - the Sigma 'response' is similar to applying a
    film-like S-curve to a typical digital camera file. The midtone contrast
    is on a much steeper curve, shadows are compressed like a photographic
    print, and highlight detail (surprisingly) is much more evident in the
    luminance channel - clouds in particular show a real texture, like old
    red-filtered monochrome prints from the 1950s when people had just
    discovered how to do that.

    Without messing with sharpening or saturation, a standard S-curve for
    contrast will do the right thing on the Minolta files to make the
    textural detail of stuff like foliage and stonework stand out almost as
    well as the Sigma. But... saveable S-curves are offered in Minolta's own
    software for raw conversion, and it is a tedious two-stage process;
    Photoshop's raw plug-in is far superior, offers much better (LAB based,
    I suspect) control over sharpness and colour smoothing and noise
    reduction, and no curves...

    It had not occurred to me to test the Sigma on a simple thing like a
    greyscale target to gauge its 'gamma' but it's very clear comparing a
    few files that a chrome-film-like on screen image is what they have
    aimed to achieve.

    Had Sigma NOT gone for:
    A film-like response curve
    A high level of saturation in all colours

    maybe their exported files would show fewer colour artefacts, because
    both the above processes emphasise problems.

    David Kilpatrick, May 19, 2004
  6. David Kilpatrick

    Lionel Guest

    Kibo informs me that (George Preddy) stated
    It sure is for you, seeing as you can't afford a real camera.

    We're still waiting to see those photos you lied about having sold.
    Why do you keep on ignoring the posts in which I ask you about those
    Lionel, May 20, 2004
  7. David Kilpatrick

    Paul Howland Guest

    George Preddy wrote:

    Talking of which, Georgy-boy, where are the samples of your professional
    photographs you keep mentioning? You've never really taken a photograph
    have you George? Go buy yourself a disposable, take some pictures, get
    them scanned in at your local store and post us the URL. Then we might
    want to listen to what you have to say.
    Paul Howland, May 20, 2004
  8. Samples? SAMPLES? *YOU* dare asking for samples? Where are those samples
    that people here have been asking yo to provide?

    Jukka-Pekka Suominen, May 20, 2004
  9. George Preddy wrote:

    I have had every Minolta 7-series since the original 7 and they have
    never given me any reason, after years rather than months, to think that
    a sealed optical path is a problem.

    David Kilpatrick, May 20, 2004
  10. David Kilpatrick

    Ray Fischer Guest

    _Especially_ when one of them is a Sigma.
    Ray Fischer, May 22, 2004
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