"Martin Baxter" wrote in message
...
Dave wrote:

On 19 Oct 2006 22:11:51 -0700, "Bart" said:

Name the two most characteristics to look for when shopping
for binoculars? [1 point each]

I'm surprised no one has mentioned light gathering capability. That's the
main reason the Navy uses 7X50s (or at least did in my day). They
provided
the best compromise of magnification and light gathering ability, coupled
with a field of view that was adequate on a moving deck.

Don't forget the diameter of the exit pupil, (objective dia./mag.),
should approximate the size of the pupil in the light conditions for
which you intend to use them. The 7X50s with a 7 mm exit diameter are a
fair compromise; the human pupil can open to about 9 mm in low light.
The typical 7X35 used by bird watchers have and exit pupil of 5 mm.

Cheers
Marty

Don't mules and asses have rectangular pupils?