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Big Binoculars for Birding Part III



Carolinabirders,

In my first two posts on this subject, I describe comparisons between my
spotting scope and my new Pentax PCF 20x60 WP binoculars.  I bought the
binoculars to use as an alternative to the scope which would offer both high
power and two-eye viewing.

At lunch time today I went outside in bright sun to make one more test of my
new optics.  There was some mild heat wave but not enough to be a problem.
I set up at about 130 yards from my target, but after some preliminary
testing, I moved up to about 100 yards from  the target -- a utility pole
which had a metal box on its side.  I wanted to read the print on the box
through the scope and binoculars.  At the top of the box was  the word
"DANGER" written in 3/4 inch high white print on a red background.  Below
this was the message "Exposed energized electrical equipment (conductors).
Authorized personnel only.  All others keep out".  This message was written
in 1/2 inch high black print on a white background.

Following are the results of my comparisons while looking at the metal box.

Swarovski 8x50 SLC binoculars -- my primary birding binoculars.  With these
resting on a tripod, I could barely make out the the word "DANGER".  I could
not read any of the smaller print, couldn't make out any of the letters.
About the best I could do was to see that there were separations between
words.

Kowa TSN-2 Spotting Scope -- my old spotting scope (20-60X Zoom eyepiece,
set at 20X).  With these resting on a tripod, I could read the entire
message, large and small print without great difficulty.

Pentax PCF 20x60 WP binoculars -- my new binoculars.  With these resting on
a tripod, I could read the entire message, large and small print without
great difficulty.

In summary, I could not really tell any difference in the Kowa scope and the
Pentax binoculars in performing this optical test.  However, I must note
that during the test, I am comparing a one-eye view through the scope with a
two-eye view through the binoculars.  When I tried to use the Pentax
binoculars with only my one dominant eye, I was not able to see nearly as
well.  In other words, the single optical tube of the Kowa scope is better
than a single optical tube of the Pentax binoculars.  In essence, what makes
these binoculars as good as the scope is two optical tubes used with two
eyes.  The brain does wonderful things with vision when it has two eyes
working together.  The brain sees a better image than either eye by itself.

Back to my Swarovski 8x50s.  No, I'm not going to throw them away.  However,
I can't expect 8X to do what 20X can do.  The extra power of the $200 Pentax
20x60s just overwhelms the $1000 Swarovski.  Some things money can't buy.
For everything else, there's Mastercard.

Now, before you run out and use your Mastercard to purchase the Pentax
binos, let me remind you of some possible drawbacks.  First, they are going
to be more subject to collimation problems from bumps and drops, because
they have porro prisms in two optical tubes that must be precisely aligned.
Second, they have a small exit pupil of only 3mm.  This means that your eyes
must line up well with the optical tubes to get the best image.  By
comparison, my Swarovski binoculars have an exit pupil of 6mm, which gives
them a very relaxed, easy view. I would describe the Pentax view as
requiring more effort.  But, I prefer the effort of using two eyes together
to the alternative of shutting one eye and squinting with the other down the
barrel of a traditional spotting scope.

John
* * * * * * * * * * * * * * * *
John and Paula Wright
1953-A Quail Ridge Rd
Greenville, NC 27858
(252) 756-5139