Pictures from Pentax *ist DS + 27-y-o Tamron 85-210 lens

Discussion in 'Pentax' started by Helen Edith Stephenson, Mar 20, 2005.

  1. I went out with the Pentax *ist DS on Friday evening, and I've put up a
    selection of my better efforts at
    http://uk.pg.photos.yahoo.com/ph/helenedithuk/album?.dir=/ee23 in an
    Album called 2005-03-18 Monument/London Bridge Area.

    The Monument was absolutely gorgeous against the sky, and these
    photos don't really do it justice. I might go back and try again using
    tungsten white balance.

    The other photos in the album were taken from the north bank of The
    Thames with a variety of white balance settings - and I've changed one
    or two a bit in PhotoShop as well.

    The lens used was my 27-year-old manual Tamron 85-210. I've used it
    quite a bit on the DS, mostly with very good results, although a couple
    of times I've got some rather peculiar red fringing with it which I
    don't recall ever seeing when I've used it on a film camera.

    I do like the 2-second mirror lock-up feature on the DS, but admit that
    it's making me lazy: I used this feature with the shutter button rather
    than putting on my cable release:)

    I did lug a tripod up to Town on this occasion, mainly because I know
    that there's no convenient bean-bag resting place near my vantage point
    for photographing The Monument. I do use a bean-bag a certain amount,
    and did so for this picture of HMS Manchester:
    http://uk.pg.photos.yahoo.com/ph/helenedithuk/album?.dir=bcb2

    One comment I have to make about using the DS for taking long exposures
    (many around 15 seconds) is that it seems to take as long to process the
    image and write it to the card as the shutter is open for; and that
    while it's doing so, it doesn't want to take another picture. So much
    for frame bursts. I am curious to see what will happen when I use the DS
    to take a *really* long exposure: if I do a 7-minute moonlight exposure,
    will it take 7 minutes before it's ready to take another picture? It's a
    full moon in about a week, and I might be tempted out into the local
    park to find out.

    HelenEdith

    Helen Edith Stephenson <helen at baronmoss dot demon dot co dot uk>
     
    Helen Edith Stephenson, Mar 20, 2005
    #1
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  2. Helen Edith Stephenson

    John Francis Guest

    I like the shot of Southwark Cathedral tower.
    That purple fringing effect is common with digital cameras.
    It can be caused by extremely high-contrast edges, or by the
    angle at which light rays fall on the sensor. As a very
    broad generalization, that is a property of the lens (and,
    with a zoom, the focal length being used).
    Yes - it will. There's a feature in the camera called Noise Reduction
    (briefly mentioned on P140 of the manual) that takes a blank exposure
    immediately after a long exposure (30 seconds or longer, I believe) to
    measure the noise in the sensor, and subtracts this from your exposure.
    This blank exposure is the same length as your original exposure.

    If you want your camera back before 7 minutes, turn the feature off.
     
    John Francis, Mar 20, 2005
    #2
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  3. That was taken with tungsten white balance. I tried one with auto white
    balance as well, but the tungsten one was better:)
    I was a bit surprised that artefacts like that would turn up when using
    a telephoto lens, as I'd assume that the light rays fall on the sensor
    at fairly close to 90 degrees. My physics isn't good enough to say
    whether that's a good assumption, but I thought it was logical and that
    the lenses where you'd need to worry about light ray angles would more
    likely be the wide angle lenses.
    Ahhhh....

    I did wonder about it taking so long before the shutter would release
    again. That sounds like a very annoying feature to have switched on if I
    decide to get into star trails and the like, so I think I'll be looking
    for that menu item. Thanks for alerting me to it.

    It could also be a serious drain on the batteries. As it was, I got onto
    a second set of rechargables on Friday evening and I only took 48
    images. I did use the back panel to do quite a bit of reviewing, though,
    which is probably heavier on batteries than actually holding the shutter
    open.

    Helen

    Helen Edith Stephenson <helen at baronmoss dot demon dot co dot uk>
     
    Helen Edith Stephenson, Mar 20, 2005
    #3
  4. Helen Edith Stephenson

    DoN. Nichols Guest

    [ ... ]
    I suspect that what it is doing is gathering statistics on the
    clocking noise and other such things with the shutter closed, to
    subtract from the actual exposure, and thus minimize visible noise.

    Enjoy,
    DoN.
     
    DoN. Nichols, Mar 20, 2005
    #4
  5. Helen Edith Stephenson

    John Francis Guest

    Shoot raw in tricky lighting, and you can make those decisions post-exposure.
    It is - much heavier. Even so, 48 is far too early to replace anything
    (except regular disposable AA batteries). Are the rechargeables new?
    It can take a few charge/discharge cycles to get everything behaving.
    Pentax claim you can get 5 hours of playback time with rechargeables.

    I use a D, not a DS. But with just one set of rechargeables (1800mAh),
    three second review, and using a current-draining microdrive I get
    several hundred exposures before needing to change (and that's before
    getting the battery grip, which doubles the number of shots available).
     
    John Francis, Mar 20, 2005
    #5
  6. There's just one problem with that: I'm still using Win98 and the RAW
    software with the DS won't work under Win98, and the PhotoShop plug-in
    for the D won't work with DS RAW files. I've got a spare partition on my
    hard drive just waiting for WinXP, but I'm trying to put off spending
    the money.

    I think I'll also need to seriously expand my collection of SD cards
    once I start shooting in RAW.
    The rechargeables I was using have been charged about ten times by now.
    I fished them out when I got a "battery low" message and put in another
    set which hadn't previously been used at all. I was a little surprised
    at how quickly they ran down, but I've had the same set of batteries run
    down completely during daytime use as well, although with about double
    that number of exposures. It will be interesting to see how the set I've
    got in the camera now perform, as they're a different brand.
    I think I need to cut down on my reviewing time. I'm still learning my
    way around the camera and have only just figured out that half pressing
    the shutter button turns off the review. I think some of my reviews have
    lasted quite a long time.

    Helen

    Helen Edith Stephenson <helen at baronmoss dot demon dot co dot uk>
     
    Helen Edith Stephenson, Mar 20, 2005
    #6
  7. You're the second person to say that:) I'm going to look into it, as I
    really don't want it to spend an inordinate amount of time on such a
    project if I'm taking exposures measured in minutes rather than seconds.
    I may prefer to live with some noise and turn the feature off.

    For exposures in the 15-30 second range, I'm prepared to live with it,
    though.

    Helen

    Helen Edith Stephenson <helen at baronmoss dot demon dot co dot uk>
     
    Helen Edith Stephenson, Mar 20, 2005
    #7
  8. Helen Edith Stephenson

    John Francis Guest

    One nice thing about digital photography is that you can change "film"
    (ISO, recording mode, etc.) for every frame.
    Ah. That may be your problem. The battery charge indicator on the
    Pentax is next to useless - if you happened to be doing too much at
    the time it decides to sample the voltage, you'll get a spurious
    "battery low" indication. Try half-depressing the shutter (or,
    if you really want to be sure, powering the camera off and back on).
    Most of the time that "battery low" indicator will go away.

    I have the review time set to three seconds. If I want to take a
    longer look at a particular shot, pushing the playback button puts
    the most recent shot on the display, and leaves it there.


    [I see you are now in the area where I grew up - I went to Chis & Sid]
     
    John Francis, Mar 21, 2005
    #8
  9. Helen Edith Stephenson

    DoN. Nichols Guest

    See what it looks like for a single long exposure before
    committing to that. I understand that with really long exposures, you
    wind up with strange patterns which are artifacts of the layout of the
    chip wiring patterns and where heat (e.g. from amplifiers) may be coming
    from. I doubt that they would add such a nuisance "feature" unless they
    felt it to be quite necessary.

    Good Luck,
    DoN.
     
    DoN. Nichols, Mar 21, 2005
    #9
  10. :
    : One comment I have to make about using the DS for taking long exposures
    : (many around 15 seconds) is that it seems to take as long to process the
    : image and write it to the card as the shutter is open for;

    It is doing noise reduction - shooting a "dark frame" as a reference.

    You can turn that off, but then you won't (natch) have noise reduction!

    And, yes, with NR on, a 7-minute exposure would take you 14 minutes.

    -Charles
     
    Charles Robinson, Mar 21, 2005
    #10
  11. Yes, it's a *huge* advantage. It's made several of my film bodies
    obsolete in one go:)
    Interesting. I noticed the other day that the battery indicator seemed
    to indicate nearly exhausted batteries one minute and then be fine again
    the next minute. I will take its messages with a pinch of salt in
    future.
    I've got the review time set to the factory default, which I think is
    rather less than three seconds. I'm forever pushing the playback button
    and leaving the most recent shot on the display.
    Yes, I've lived in the Bromley area for a good many years now, although
    I'm Antipodean by birth:)

    Helen

    Helen Edith Stephenson <helen at baronmoss dot demon dot co dot uk>
     
    Helen Edith Stephenson, Mar 21, 2005
    #11
  12. That's good advice. Chip wiring patterns would be unlikely to enhance my
    photography:) Some experimentation is in order.

    Helen

    Helen Edith Stephenson <helen at baronmoss dot demon dot co dot uk>
     
    Helen Edith Stephenson, Mar 21, 2005
    #12
  13. :-(

    Some experimentation is definitely in order here. It depends on what the
    noise actually looks like, but if it just gives the image grain, it
    might be quite acceptable. If it turns out to be chip wiring patterns,
    then I think I'm stuck with it.

    Helen

    Helen Edith Stephenson <helen at baronmoss dot demon dot co dot uk>
     
    Helen Edith Stephenson, Mar 21, 2005
    #13
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