F stops

Discussion in 'Australia Photography' started by Don, Jul 13, 2003.

  1. Don

    Don Guest

    Recently I noticed somewhere (cant recall where now off course) that
    somebody had stated that the F stop in a digital is not as critical or does
    not match that of a "normal" camera. I own a cp5700 and the only issue I
    have with it is that it doesn't have an aperture range past f8.0. As I was
    intending to be a budding Ansel Adams I wondered if there is a difference in
    the aperture size and how do I compensate for not having a larger aperture
    range so that I can ensure a large depth of field.

    ps remember we are not all as technically minded or informed as some so
    please keep the smart arse comments to a minimum.

    Look forward to being informed
    Don, Jul 13, 2003
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  2. Don

    Miro Guest

    As I was intending to be a budding Ansel Adams .......

    I take it you have all his books and all his posters. Perhaps you might
    consider using a camera that can be controlled ?

    For the cost of the 5700 you could have bought a b&w film processing kit, a
    camera and a light meter.
    Miro, Jul 13, 2003
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  3. Don

    Ken Chandler Guest

    G'day Don,
    The apparent depth of field on a consumer digital camera (like the 5700) is
    much greater than a "normal" 35mm film camera, WHEN talking about the same
    field of view and the same f/stop.
    You are fairly well assured of a large depth of field using the 5700 due to
    it's relatively small imaging sensor (CCD) and actual focal length of the
    lens, 8.9-71.2mm (35-280mm 35mm equiv. field of view)

    For example, say you are taking a photo of a tree 10 metres away using a
    50mm equivalent field of view, and an aperture of f4.

    At 50mm equiv. (12.6mm) The Nikon Coolpix 5700 would give a limit of
    acceptable sharpness of approx.:

    Near: 3.32m
    Far: Infinity

    compare this with a 35mm camera with a similar field of view:

    Near: 6.77m
    Far: 19.1m

    (Source: http://dfleming.ameranet.com/dofjs.html)
    Hope that helps,

    Regards, Ken
    Ken Chandler, Jul 13, 2003
  4. Don

    Ken Chandler Guest

    ** added back the name of the person Miro was quoting **
    Yes Don, Miro has offered a good suggestion, may I suggest something like
    the Coolpix 5700?

    It has Aperture priority, Shutter priority and Manual along with a whole
    bunch of other settings to play with.

    What? You have a Coolpix 5700? What was Miro talking about then? Maybe he
    was just being obtuse and intentionally argumentative again.
    He could have bought ~520 toothbrushes too, I'm guessing he didn't want 520
    toothbrushes though.
    Ken Chandler, Jul 13, 2003
  5. Don

    Miro Guest

    Ken I think you have the same mental condition that Mr Shutterbug has.
    Anyone that knows the work of Adams will be aware of his philosophy.

    Clearly Don wants to go beyond the cameras limits and clearly he is pissing
    in the wind with a tool that is that limited.
    Miro, Jul 13, 2003
  6. Don

    ops Guest

    I don't think that is a good analogy to compare a small sensor digital
    camera with a 2/3 or full frame sensor.

    IMO they are hopeless to achieve a successful result compared to 35mm film.

    ops, Jul 13, 2003
  7. Don

    Don Guest

    Thanks, for all the good oil. On a separate note, I have a Pentax 35mm with
    all the bells and whistles but prefer using the CP5700 for "in training"
    shots as I can bolt back home and throw the shots on to the monitor to see
    how I went.

    Today is a classis example. I went looking for some moving water in a creek
    to shoot hoping to get the milky smoothness that I have seen in various
    mags. Had to shoot upstream and into the sun. Ended up with in excess of
    100 shots. None of them any good. Tried bracketing, slow shutter, large
    aperture, grey card, auto, manual, etc etc. Still ended up with overcooked
    water no matter what settings I used. Only thing I didn't try that I can
    think of was a polariser or neutral density focus. Just couldn't get the
    exposure correct. List below of various exposures (all 100ISO):

    1/1,000 f3.1 fl 14.7mm (bracket all around this ranging from .3ev to 2.0 ev
    + & -
    1/30 f3.1 fl 14.7mm (bracket all around this ranging from .3ev to 2.0
    ev + & -
    1/7.5 f3.1 fl 14.7mm (bracket all around this ranging from .3ev to 2.0
    ev + & -
    1/60 f3.1 fl 14.7mm (bracket all around this ranging from .3ev to 2.0
    ev + & -
    1/15 f3.1 fl 14.7mm (bracket all around this ranging from .3ev to 2.0
    ev + & -
    1/120 f3.1 fl 14.7mm (bracket all around this ranging from .3ev to 2.0
    ev + & -
    and more at the same f-stop and focal length, then tried different stops
    7.9, 7.4, 7.1, 8, 4 etc etc.
    just couldn't nail it. either over exposed or under. The site was a gully
    with creek in middle, lots of trees, clouds (got the white balance down well
    on virtually all shots (used auto white bracketing). Spot metering and
    matrix. All shots on same focal length. Some of the shots were of a point
    and shoot snap, standard. However I am hoping for better.

    Any suggesting (of merit please)


    Don, Jul 13, 2003
  8. Don

    Ken Chandler Guest

    The moving water should also bubble or tear in areas of white eg over rocks
    etc, it is these white areas that will convey the movement over a prolonged
    exposure. If the water is flowing without many visual clues then capturing
    the movement on film is going to be tough.
    Generally for a long exposure you are going to want to be in a darker area
    or otherwise have enough neutral density filters to reduce the light enough
    for you to get the shutter time you are after at the aperture range you have
    to work with.

    If there is a large difference between say a bright sky and a river in
    shadows you may require a graduated neutral density filter to bring the
    whole scene within the range your camera can deal with.
    [snipped large sample of settings]
    Perhaps post a link to a sample of the scene you were trying to capture so I
    (we?) can get a better idea of what you had to work with.

    Here is one of my earlier attempts:


    Ken Chandler, Jul 13, 2003
  9. Don

    Miro Guest

    Its good to experiment but I think the idea of shooting is to think before
    you press the button. Unless it is sport there is no need to shoot first and
    think second.

    Have you read Adams's books ?
    Miro, Jul 13, 2003
  10. Don

    Lionel Guest

    Or he was being just plain stupid, as usual.
    Lionel, Jul 13, 2003
  11. Don

    Miro Guest

    " It has Aperture priority, Shutter priority.........." - is this the same
    as manual control ? Idiot.
    Miro, Jul 13, 2003
  12. Don

    Ubiquitous Guest

    The CP5700 has full manual controls too.

    Ubiquitous, Jul 13, 2003
  13. Don

    Miro Guest

    And they are highly constrained in range.
    Miro, Jul 13, 2003
  14. Don

    Bruce Murphy Guest

    Really? are the shutter speed options more highly constrained than,
    say, a Leica? Looks like 1/4000 to 8s on the specs I can find. That's
    a lot better than one of those 'constrained' Leicas.

    Sure, the aperture range isn't as much as you might like but that's a
    lot to do with effective DoF and diffraction limits.

    Glad to see you're giving the full story as usual, oh great idiot.

    Bruce Murphy, Jul 13, 2003
  15. Don

    Danny Smith Guest

    Without wanting to be drawn into a good Miro-bashing (well, not today)
    so without wandering into an actual discussion, that's a very handy
    website, Ken.

    I admit that this is completely beyond me in terms of optics and
    calculations, but:

    Does anyone know how they determine 'acceptable' sharpness? I can see
    how it's calculated based on Circle of Confusion, but wouldn't the CoC
    size differ based on display/print size/pickiness?

    It seems to be based on a CoC for 35mm film of 0.030 mm - anyone know
    if this corresponds to a particular print size?

    Or am I completely misunderstanding the whole CoC concept somehow?


    Danny Smith, Jul 14, 2003
  16. Don

    Bruce Murphy Guest

    Coward! :)
    There is an implicit assumptions that any given print size will have a
    'normal viewing distance' which is based on its linear
    size. Basically, your distance from a print when viewing it will be
    directly proportional to the size of the print (I recall one example
    being 'approximately the diagonal length away from it').

    This permits the CoC definition to stand and solves the issue you spotted.
    Bruce Murphy, Jul 14, 2003
  17. Don

    Lionel Guest

    Jeez! - Surely you don't expect Miro to have to check the actual *facts*
    before making one of his obnoxious comments? The poor bugger wouldn't
    be able to post at all!
    Lionel, Jul 14, 2003
  18. Made sense to me.....
    But then I'll get flamed as a top poster probably......

    Yes I recall now ... this is Bruce Murphy style in action. Random splices of
    English like DNA in a blender muddled and jumbled - SEND.

    Do you follow the thread of this conversation at all or does it now have to
    conform to your preferences.

    Naturally you are hijacking the thoughts again ..... may we speak now ?
    Thomas Houseman, Jul 14, 2003
  19. Don

    Bruce Murphy Guest

    Even if you top-post (which is an abomination under the eyes of
    USENET) you should still make sure your client marks quote text by
    indenting it with '>' so that people know what *you* wrote withing
    having to compare it against the previous post.

    Bruce Murphy, Jul 14, 2003
  20. Don

    Miro Guest

    You really do have a "special" problem I sense. The poster is complaining
    about the lack of f-stop range. Is that somehow lost on your ADD mind.
    Miro, Jul 14, 2003
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