I concur. Maybe someday I'll again run across the SDO that put forth
that American standard. Then we can comment directly. Personally, I'm
for just one set of units, namely meters.
Jim
John M. Steele wrote:
The field of view spec in feet at 1000 yards is a bit troubling on two
counts:
*Most Americans don't use the yard much except in football and I doubt
they could describe what 1000 yards is, or estimate it
*It forces metric countries (and people) to remember there are 3 feet in
a yard.
If they expressed it as 105 feet at 1000 ft, it would be
"non-denominational," it wouldn't matter if the units were feet, yards,
meters, chains, whatever. An industry practice to use only "units at
1000 units" where "units" can be chosen for the market would be a better
practice.
------------------------------------------------------------------------
*From:* James R. Frysinger <[email protected]>
*To:* U.S. Metric Association <[email protected]>
*Sent:* Wed, April 28, 2010 3:11:57 PM
*Subject:* [USMA:47290] Canon binoculars, SI IS directions
I've just purchased a set of Cannon binoculars (10x30, IS) via Amazon.
The directions that accompany them describe the alternatives for types
of batteries to use for the image stabilization (IS). In part the
directions read,
"Although lithium batteries work well in low temperature, their
performance will drop slightly in temperatures below 0 degrees C."
Let's not waste time fussing about "degrees C" instead of "degrees
Celsius" or "°C". There is no explanation nor conversion to Fahrenheit
applied to that statement about lithium batteries. Totally metric! If
you don't get it, you should have stayed awake in your science classes.
Of course, the second figure in "10x30" is the objective lens diameter
in millimeters. I daresay that many Americans don't know that.
In the specifications section of the English section of this
multi-language booklet, however, the temperature range, size, and weight
are given in metric, followed by a slash (/), and then by figures in
inches, degrees Fahrenheit, etc. An exception to that is the field of
view "at 1000 yds." which is specified as "314 ft.". This is a standard
of the industry and I seem to recall that it is specified by ASTM. (In
the other language sections, the field of view is given as 105 m at 1000
m.) The minimum focal length is given as "Approx. 13.8ft to infinity".
(In the other language sections they specify 4.2 m.) The exit pupil
diameter and eye relief distances are given only in millimeters (3 mm
and 14.5 mm, respectively).
Most folks won't read the specifications page. They are much more likely
to read just the few pages of directions and there they will not
encounter any non-SI units.
Jim
-- James R. Frysinger
632 Stony Point Mountain Road
Doyle, TN 38559-3030
(C) 931.212.0267
(H) 931.657.3107
(F) 931.657.3108
--
James R. Frysinger
632 Stony Point Mountain Road
Doyle, TN 38559-3030
(C) 931.212.0267
(H) 931.657.3107
(F) 931.657.3108
