Sony DoF Equivalency

Discussion in 'Digital Photography' started by Andrew Brydon, Jun 15, 2011.

  1. I was bought a Sony DSC TX5 as a gift. It's marketed as being
    weather-proof (rain, snow, dust, shock) which I was to use whilst
    hiking in the hills. Landscapes were therefore a prime intended
    use (reportage) - nothing fancy. Except using its "landscape"
    mode the shots were never stopped beyond f5.6 which seemed (to me)
    to be an awfully tight DoF for landscape.

    So I email Sony and they phone back. "Have you tried manual mode?"
    they ask. It doesn't have manual mode! "Are you really from Sony?"
    I ask. Anyway - since I didn't have the manual or box handy where
    they phoned me, I asked for the camera's stated aperture range.
    3.5 to 4.6. Rubbish says I, I'd taken at f5.6. He checks again.
    Definitely 3.5-4.6, but "that's equivalent to f5.6".

    I've obviously missed something - how does 4.6 be equal to f5.6?

    TIA.
    --
    Andrew Brydon
    Life is just the beta-version of death
     
    Andrew Brydon, Jun 15, 2011
    #1
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  2. "Andrew Brydon" <> wrote in message
    news:4df83786$0$2522$...
    > I was bought a Sony DSC TX5 as a gift. It's marketed as being
    > weather-proof (rain, snow, dust, shock) which I was to use whilst
    > hiking in the hills. Landscapes were therefore a prime intended
    > use (reportage) - nothing fancy. Except using its "landscape"
    > mode the shots were never stopped beyond f5.6 which seemed (to me)
    > to be an awfully tight DoF for landscape.

    []
    > TIA.
    > --
    > Andrew Brydon


    Andrew,

    Small-sensor cameras have a larger depth-of-field at a given aperture than
    large sensor cameras (e.g. SLR), so f/5.6 may well be quite adequate.
    Because diffraction is so much greater in such cameras (as the sensor
    elements are much smaller), lenses are not allowed to stop down as low as
    f/22, f/32 etc.

    Cheers,
    David
     
    David J Taylor, Jun 15, 2011
    #2
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  3. Andrew Brydon

    Bruce Guest

    "David J Taylor" <> wrote:
    >
    >Small-sensor cameras have a larger depth-of-field at a given aperture than
    >large sensor cameras (e.g. SLR), so f/5.6 may well be quite adequate.



    Agreed.


    >Because diffraction is so much greater in such cameras (as the sensor
    >elements are much smaller), lenses are not allowed to stop down as low as
    >f/22, f/32 etc.



    As with so many of your statements based on theory, that statement is
    theoretically true. However, in the real world, the reason why the
    minimum size of the aperture is limited is because controlling smaller
    apertures to the required accuracy would be impracticable.

    Practical considerations therefore dictate that smaller apertures
    cannot be provided. The avoidance of diffraction is a very welcome
    by-product but *not* a primary design objective.
     
    Bruce, Jun 15, 2011
    #3
  4. Andrew Brydon

    me Guest

    On Wed, 15 Jun 2011 05:39:34 +0100, Andrew Brydon
    <> wrote:

    >I was bought a Sony DSC TX5 as a gift. It's marketed as being
    >weather-proof (rain, snow, dust, shock) which I was to use whilst
    >hiking in the hills. Landscapes were therefore a prime intended
    >use (reportage) - nothing fancy. Except using its "landscape"
    >mode the shots were never stopped beyond f5.6 which seemed (to me)
    >to be an awfully tight DoF for landscape.
    >
    >So I email Sony and they phone back. "Have you tried manual mode?"
    >they ask. It doesn't have manual mode! "Are you really from Sony?"
    >I ask. Anyway - since I didn't have the manual or box handy where
    >they phoned me, I asked for the camera's stated aperture range.
    >3.5 to 4.6. Rubbish says I, I'd taken at f5.6. He checks again.
    >Definitely 3.5-4.6, but "that's equivalent to f5.6".
    >
    >I've obviously missed something - how does 4.6 be equal to f5.6?


    http://www.dpreview.com/products/sony/compacts/sony_dsctx5

    Maximum aperture F3.5 - F6.3
     
    me, Jun 15, 2011
    #4
  5. On 15/06/2011 20:47, me wrote:
    > On Wed, 15 Jun 2011 05:39:34 +0100, Andrew Brydon
    > <> wrote:
    >
    >> I was bought a Sony DSC TX5 as a gift. It's marketed as being
    >> weather-proof (rain, snow, dust, shock) which I was to use whilst
    >> hiking in the hills. Landscapes were therefore a prime intended
    >> use (reportage) - nothing fancy. Except using its "landscape"
    >> mode the shots were never stopped beyond f5.6 which seemed (to me)
    >> to be an awfully tight DoF for landscape.
    >>
    >> So I email Sony and they phone back. "Have you tried manual mode?"
    >> they ask. It doesn't have manual mode! "Are you really from Sony?"
    >> I ask. Anyway - since I didn't have the manual or box handy where
    >> they phoned me, I asked for the camera's stated aperture range.
    >> 3.5 to 4.6. Rubbish says I, I'd taken at f5.6. He checks again.
    >> Definitely 3.5-4.6, but "that's equivalent to f5.6".
    >>
    >> I've obviously missed something - how does 4.6 be equal to f5.6?

    >
    > http://www.dpreview.com/products/sony/compacts/sony_dsctx5
    >
    > Maximum aperture F3.5 - F6.3
    >

    Sony's website states F3.5 - F4.6, which is presumably what their
    customer help drone was repeating from. As follow up to both my
    original and the replies (for which many thanks) their customer
    service desk clearly doesn't know how the camera works. They would
    seem not to believe that the camera itself is reporting "implied"
    aperture (i.e. 35mm equivalent) rather than "actual". They apparently
    didn't believe I had been taking images at F5.6 and asked me to email
    them a sample to prove it...

    --
    Andrew Brydon
    Life is just the beta-version of death
     
    Andrew Brydon, Jun 17, 2011
    #5
  6. Andrew Brydon

    Bruce Guest

    Andrew Brydon <> wrote:
    >On 15/06/2011 20:47, me wrote:
    >> On Wed, 15 Jun 2011 05:39:34 +0100, Andrew Brydon
    >> <> wrote:
    >>
    >>> I was bought a Sony DSC TX5 as a gift. It's marketed as being
    >>> weather-proof (rain, snow, dust, shock) which I was to use whilst
    >>> hiking in the hills. Landscapes were therefore a prime intended
    >>> use (reportage) - nothing fancy. Except using its "landscape"
    >>> mode the shots were never stopped beyond f5.6 which seemed (to me)
    >>> to be an awfully tight DoF for landscape.
    >>>
    >>> So I email Sony and they phone back. "Have you tried manual mode?"
    >>> they ask. It doesn't have manual mode! "Are you really from Sony?"
    >>> I ask. Anyway - since I didn't have the manual or box handy where
    >>> they phoned me, I asked for the camera's stated aperture range.
    >>> 3.5 to 4.6. Rubbish says I, I'd taken at f5.6. He checks again.
    >>> Definitely 3.5-4.6, but "that's equivalent to f5.6".
    >>>
    >>> I've obviously missed something - how does 4.6 be equal to f5.6?

    >>
    >> http://www.dpreview.com/products/sony/compacts/sony_dsctx5
    >>
    >> Maximum aperture F3.5 - F6.3
    >>

    >Sony's website states F3.5 - F4.6, which is presumably what their
    >customer help drone was repeating from. As follow up to both my
    >original and the replies (for which many thanks) their customer
    >service desk clearly doesn't know how the camera works. They would
    >seem not to believe that the camera itself is reporting "implied"
    >aperture (i.e. 35mm equivalent) rather than "actual". They apparently
    >didn't believe I had been taking images at F5.6 and asked me to email
    >them a sample to prove it...



    There is no such thing as a "35mm equivalent aperture". Regardless of
    the sensor or film size, the aperture is expressed as a ratio of the
    effective light-transmitting aperture of the lens (in millimetres) to
    the focal length of the lens (f, in millimetres).

    A small sensor camera gives exceptional depth of field even with an
    aperture (f number) that on 35mm film might seem far too wide.

    In fact one of the greatest weaknesses of a small sensor camera is its
    inability to offer any control over depth of field. Everything is in
    focus all the time. When you want to separate the subject from the
    background by defocusing the latter, you can't.

    So don't obsess about f/4.6, f/5.6 or f/6.3. If you were using a 35mm
    film camera or a full frame digital SLR, these apertures would indeed
    give you the restricted depth of field that you are concerned about.
    But on a small sensor digital camera they will give you plenty of
    depth of field, even when you don't need it.
     
    Bruce, Jun 17, 2011
    #6
  7. Andrew Brydon

    John Turco Guest

    Bruce wrote:

    <edited for brevity>

    > A small sensor camera gives exceptional depth of field even with
    > an aperture (f number) that on 35mm film might seem far too wide.
    >
    > In fact one of the greatest weaknesses of a small sensor camera
    > is its inability to offer any control over depth of field.


    Ha!

    > Everything is in focus all the time. When you want to separate
    > the subject from the background by defocusing the latter, you
    > can't.


    <edited>

    That's a gross oversimplification, "Bruce." The vast majority of
    compact "P&S" cameras' lenses, are of fairly short focal lengths.
    It's this fact (plus their somewhat narrow apertures) that endows
    them with inherently great "DOF" (depth of field).

    "Super zoom" digicams are much bigger, but, also use tiny sensors.
    Notwithstanding, they offer more control of DOF, because of their
    telephoto capabilites.

    I know so, from experiece. My three Kodak models (DX6490, P850
    and Z980) have 10x, 12x and 24x zoom ratios, respectively. Each
    can capture images with extremely blurred backgrounds, whenever
    the operator has even a modicum of know-how ...which, of course,
    automatically excludes >you<.

    --
    Cordially,
    John Turco <>

    Marie's Musings <http://fairiesandtails.blogspot.com>
     
    John Turco, Jun 30, 2011
    #7
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