Announcement: new DoF calculator available for download

Discussion in 'Digital Photography' started by Jens Regge, Oct 5, 2004.

  1. Shiver me timbers!

    The original mile was, of course, based on a decimal system, being the
    Roman /mille passus/, or a thousand paces. That's about 1,620 yards or 1.4
    kilometres in today's money.
    Roger Whitehead, Oct 7, 2004
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  2. Jens Regge

    Colin D Guest

    Those Romans must have had helluva long legs, then - 1,620 yards in
    1,000 paces - lessee, that's 1.62 yards per pace, or 4.86 feet, or in
    metric terms, 1.48 metres per pace!!! I'm not exactly short, but I have
    trouble pacing out 1-metre steps, and if I recall correctly, the
    regulation length of a military pace is one yard.

    Colin D, Oct 7, 2004
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  3. Jens Regge

    Peter Irwin Guest

    What the Romans counted as a pace, you would count as two.
    Walk normally, and count every time your right foot touches
    the ground. One thousand of those is a mile.

    Peter Irwin, Oct 7, 2004
  4. Sinister DEXTER, sinister DEXTER...
    Roger Whitehead, Oct 7, 2004
  5. Yes....In the military, we generally considered a "pace" to be 5 feet. It
    consisted of two steps.......
    William Graham, Oct 7, 2004
  6. Just standard design considerations. Did I mention that I used to design
    boxes? ;-)
    Great idea! Now how does it fasten securely with proper security for
    contents? And how do all the boxes stack when full still keeping their
    contents secure? And do those boxes fit in an outer or on a pallet with no
    wasted space and still all secure? And when the boxes are empty can you
    make them nest inside one another so they don't take up too much room on
    initial delivery?
    John Cartmell, Oct 7, 2004
  7. And don't forget the requirement that they have to absorb 50% of the sound
    that strikes them when they are empty, so rock groups can use them for sound
    absorbing wall coverings in their studios.........
    William Graham, Oct 7, 2004
  8. Jens Regge

    Colin D Guest

    Aha. Two steps = one pace. Gotcha.
    Colin D, Oct 7, 2004
  9. Preferrably 99%! The bands I worked with in the 60s were bad enough but the
    noise appears to have deteriorated since then...

    ...or is that simply a function of age? ;-)
    John Cartmell, Oct 7, 2004
  10. Jens Regge

    Bandicoot Guest

    I was always slightly amused by the standard sizes for Quickfit laboratory
    glass ware, which is denominated in millimetres and is described by two
    numbers that mean the length and the major diameter of the ground glass cone
    used for joining items. Standard sizes are 14/23, 19/27, and other odd
    sounding numbers. When you look closer, they are all just approximations of
    the inch fractions the stuff always was, and still is, made in. They just
    re-named it, and kept the old sizes.

    Bandicoot, Oct 7, 2004
  11. Jens Regge

    Peter Chant Guest

    OK, I'll get back in mine...
    Easy, one base and three 'leaves' that fold out. They are held shut
    with a clip at the top.

    Perhaps it would be arranged so the bases interlocked so to stack them
    you simply form a triangle, place the next smaller layer on top upside
    down to form a larger pyramid. A second advantage, the rain would run off.

    As for the pallet issue, triangular pallets.

    Peter Chant, Oct 7, 2004
  12. The best example of this was something I saw in a GM service manual
    for the 1980 X-body cars, GM's first metric North American car (and
    yes, cars are metric in the U.S. these days).

    Anyway, there was a warning at the front of the manual about the
    6.35mm bolt. When you're General Motors, you can get fasteners made in
    any size you want, so they used a number of these metric 1/4-inch
    bolts (and presumably nuts) in the car. The trick was that they used
    metric thread pitch! So you could have a nut of exactly the right
    diameter to fit on the bolt, but still damage the threads because the
    thread pitch was different.
    Stephen H. Westin, Oct 7, 2004
  13. Jens Regge

    Alan Browne Guest

    I never suggested that a package should hold 11 eggs, simply that people don't
    neccesarilly consume eggs based on the packaging. Here we can get eggs packed
    6,8,10,12,15,18,24 and 72. And they stack very nicely. The minimum size that
    would be stable would 4 (2x2) and that would stack just as well, but be a bit
    inefficient wrt to materials.

    If by container you mean those that are transported on ships and trucks, then
    the deciding factor is the width of roads and clearance under bridges.

    And all of the above have nothing to do with the metric system (or photography).



    "I told my wife the truth. I told her I was seeing a psychiatrist.
    Then she told me the truth: that she was seeing a psychiatrist,
    two plumbers, and a bartender."
    --Rodney Dangerfield (1921 - 2004).

    -- user resource:
    -- e-meil: there's no such thing as a FreeLunch.--
    Alan Browne, Oct 7, 2004
  14. Jens Regge

    Alan Browne Guest

    William Graham wrote:

    The primary legal weights and measures of the US is metric. However, the law
    allows for traditional measures to be used in commerce. The auto makers would
    be very happy to switch as they retool often and it would be easier to access
    worldwide purchassing. Aerospace does not like it, as their tooling cycle is
    much longer (decades). (OTOH no senator or congress critter has the balls to
    suggest metric roadsigns on the interstate...)

    Housewives would probably adapt to metric quicker than most. My parents were
    based in Germany in the late 50's and my mother shopped on the local economy for
    groceries. She had no trouble at all with metric (back when it was quite an
    unknown for most North Americans). Americans currently buy most soft drinks and
    wine in metric packaging and nobody has died from it. Housewives should love to
    be told they weigh "100". And unfortunately in the US, many housewives DO weigh
    100 ... kgs.

    The great number of Americans who serve in the armed forces also generates
    awareness of the metric system as the US armed forces have been heavilly
    metricised since the formation of NATO. The Army and Marines mostly, Air Force
    then Navy in terms of adaptation. Pretty much all nav system specs I've seen
    from all US services are metric for most parameters, with some traditional units
    like knots, nautical miles, lat/long, etc. for outputs. Most military nav
    systems display and allow entry of lat/long coordinates for long distance nav
    and UTM coordinates for short range/tactical navigation (same ref. as the ground
    pounders, UTM is a metric grid system).



    "I told my wife the truth. I told her I was seeing a psychiatrist.
    Then she told me the truth: that she was seeing a psychiatrist,
    two plumbers, and a bartender."
    --Rodney Dangerfield (1921 - 2004).

    -- user resource:
    -- e-meil: there's no such thing as a FreeLunch.--
    Alan Browne, Oct 7, 2004
  15. Jens Regge

    Alan Browne Guest

    Oddly enough, in radar we often use feet rather than meters when discussing
    engineering problems. Due to the speed of light being close to 1
    foot/nanosecond, it is very practical to think in terms of feet when discussing
    range gates, prf, etc.



    "I told my wife the truth. I told her I was seeing a psychiatrist.
    Then she told me the truth: that she was seeing a psychiatrist,
    two plumbers, and a bartender."
    --Rodney Dangerfield (1921 - 2004).

    -- user resource:
    -- e-meil: there's no such thing as a FreeLunch.--
    Alan Browne, Oct 7, 2004
  16. Jens Regge

    The Wogster Guest

    They do in Canada as well, 100,000km is only around 60,000 miles, so I
    guess they changed it to allow more distance, my car currently has over
    300,000km on the clock, and a previous one died at 280,000km so 6 digits
    is quite reasonable. They do still show MPH here, as a smaller number,
    and probably will do so, until the US decides to change, probably
    somewhere around the year 79875..... Most Canadians are bi-measurment
    , in that we deal with temperatures in Celsius and distances in
    kilometers, but yeah, a 2x4 is still a piece of wood 1 3/4" x 3 1/2" in
    I think this is because they are mandated by law to be a certain size,
    and the government didn't round the sizes when it metricated the law,
    they just did a simple conversion, 350ml would make more sense. Look at
    pop bottles for example, 350ml(cans) 400ml, 500ml, 1l, 2l.
    The Wogster, Oct 7, 2004
  17. Dozens and grosses can be better bases for packaging and calculation than
    10s - and packaging (or at least packing) has a great deal to do with
    photography from the light collection in digital cameras to some of the
    best photographic effects available eg honey-combs and pigeon holes.
    John Cartmell, Oct 7, 2004
  18. Jens Regge

    Alan Browne Guest

    I can't see Roger's post. I never said it was the "original mile". I was
    referring to "Mouton's _mille_" and to the "Admiralty Mile" commonly called
    today the Nautical mile which was independant from any other "mile". My
    statement above remains true, but should have been more clearly: "A minute of
    arc __on the earth's surface__ is very nearly one (1) nautical mile". Hence,
    the nautical mile is not at all decimal in origin.

    the Roman foot, equal to 29.67 centimeters (about 11.68 inches). The pes
    was divided into 12 unciae (inches). There were 5 pes (or pedes) in 1 passus
    (pace, see above), 10 in a decempeda, 625 in a stadium, and 5000 in the Roman mile.

    mile (mi) [1]
    a traditional unit of distance. The word comes from the Latin word for
    1000, mille, because originally a mile was the distance a Roman legion could
    march in 1000 paces (or 2000 steps, a pace being the distance between successive
    falls of the same foot). There is some uncertainty about the length of the Roman
    mile. Based on the Roman foot of 29.6 centimeters and assuming a standard pace
    of 5 Roman feet, the Roman mile would have been 1480 meters (4856 feet);
    however, the measured distance between surviving milestones of Roman roads is
    often closer to 1520 meters or 5000 feet. In any case, miles of similar lengths
    were used throughout Western Europe. In medieval Britain, several mile units
    were used, including a mile of 5000 feet (1524 meters), the modern mile defined
    as 8 furlongs (1609 meters), and a longer mile similar to the French mille (1949
    meters), plus the Scottish mile (1814 meters) and the Irish mile (2048 meters).
    In 1592, Parliament settled the question in England by defining the statute mile
    to be 8 furlongs, 80 chains, 320 rods, 1760 yards or 5280 feet. The statute mile
    is exactly 1609.344 meters. In athletics, races of 1500 or 1600 meters are often
    called metric miles. See also nautical mile.


    See above.



    "I told my wife the truth. I told her I was seeing a psychiatrist.
    Then she told me the truth: that she was seeing a psychiatrist,
    two plumbers, and a bartender."
    --Rodney Dangerfield (1921 - 2004).

    -- user resource:
    -- e-meil: there's no such thing as a FreeLunch.--
    Alan Browne, Oct 7, 2004
  19. Jens Regge

    The Wogster Guest

    The carton of eggs in the fridge is 2 rows of 6, a 18 egg carton is 3
    rows of 6. You could easily make that 2 rows of 5 or 3 rows of 5, and
    nobody would really care, other then those who need an extra 2 or 3
    eggs. If they ever did change it though, the price would probably stay
    the same, and that would be a bigger issue then anything else.

    There are natural measurements, for example a day is based on a eqinox
    sun-rise to sun-rise. And there are artifical measurments, for example
    hours, minutes, seconds. You can replace an artificial measurement
    with another artifical measurement, without making anything different.

    The Wogster, Oct 7, 2004
  20. Automobiles are metric. The first all-metric designs in North America
    came out in the early '80s: GM X-body (Citation, Phoenix, Skyhawk, Omega)
    and Ford Escort. Everything since has been metric.
    Well, it was done back in the '70s. This is the effort to which
    William refers. We had dual road signs as a first step toward pure
    metric. But then came the Reagan laissez-faire era.
    Yeah, my impression was that metric resistance was mainly on the part
    of various industry and business groups; mechanics don't want to buy
    new tools, etc.

    Stephen H. Westin, Oct 7, 2004
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