University Lowbrow Astronomers

A Review: IS Binos.

by Mark Vincent, Ph.D
Printed in Reflections: June, 2002.

How many of you drooled over the Sky & Telescope reviews of the image stabilized binoculars?  Come on admit it, you’re LOWBROWS.  I KNOW you slobbered all over those pages.  If you didn’t salivate over the thought of owning a pair, you’re NOT a self-respecting Lowbrow.  (OK, self-respecting and Lowbrow may just be an oxymoron.)  As I understand, you already have the good fortune to use a pair of Canon 15x50 image stabilized binoculars.

Well, I did too.  I liked my pair of Canon 12x36’s so much, that somehow a pair of 15x50’s recently acquired me as an owner....

That said, I suppose you’d like to read a real rocket scientist, Prez Emeritus’s review of these image stabilized acquisitions.  Such a review does require a dark sky - an hour’s drive east-north-east of Broomfield get skies dark enough for the winter Milky way to standout nicely.  To judge the optical performance of the 15x50’s, I compared them to my trusty, but old 1988 vintage Meade 11x80’s.  To be fair, I wore my thick “Coke bottle” glasses with both.  The 11x80’s cannot provide the -11 diopters of correction required by my nearsightedness (ya’all remember all those out of focus telescopes that I’ve walked away?).  Both the Canons just accommodate my myopia.  The true field of view for both encompassed Orion’s belt - 11x80’s easily, a bit of vignetting with the 15x50’s.  Orion nebula appeared larger and much contrastier with the latter, as expected.  It is nice that a 15 power binoculars has just enough eye relief to accommodate eyeglasses.  Without eyeglasses, the 15x50’s has a true field of view equal to the 11x80’s - kudos to the stunning 67 degree apparent field of view.

Now the ultimate test under a dark sky.  I looked around the southwest corner of the big dipper while it was at about 40 degree elevation (now without glasses).  Would you believe that M97 is faint, but easy!?  I’d be stretching it if I claimed that the Owl eyes were visible, so I won’t.  M108 is harder to view, but still there as a nice, small faint n’ fuzzy.  I then tried for M109, but no joy.  Either M109 is too faint, or I forgot where to look.  Probably the latter, since I would have missed M97 had I not remembered its exact location.  By the way, I didn’t even try for these objects with the 11x80’s.

For the big, not so faint and definitely fuzzies:  M31 goes on for one and a half fields with the 15x80 (no glasses), but barely one field with the 11x80’s.  M33 was obvious with the 15x50.  I got the impression that had I looked at M33 longer, I might have even seen some structure.  M33 was just a faint fuzzy that blended into the background through the 11x80’s.  The 15x50’s high power, small exit pupil and excellent optics made for nice large, high contrast images 8-)

On the small and/or bright, the image stabilized binocs do a pretty good job on those too.  Would you believe that a dark space between Saturn’s disk and its ring is just visible with the 15x50’s?  I suspected it, but my slight astigmatism made it difficult to be sure.  A Longmont Astronomical Society member happily confirmed the detection.  During the November occultation of Saturn by the gibbous Moon, the 12x36 revealed the rings and the disk, but not quite separated.  Later, when the Moon was nowhere nearby, Saturn appeared as just a bright, oblong blob.  For probably the first time and only time, I was praising the light pollution from the Moon.  The Moon’s light had reduced the contrast between the planet and sky to the level where Saturn was not saturating my retinas.  With both IS binocs, Jupiter’s disk is resolved, but saturated.  The Galilean satellites are easily visible, even close-up to the disk.

The Moon itself resolves beautifully into a mass of craters with very little aberrant color against a dark background!  Both binoculars display ghost images when viewing about 1.5 fields of view away the Moon.  Internal reflections within 12x36’s generate a complete circle around the Moon with a radius of about 1.5 fields of view.  Generally, only minimal ghosts and minor flares appear through the 15x50’s except for when the full moon is placed off to the side.  Overall, both perform pretty darn well.

Now the downsides of the 15x50’s.  Three words about the eyecups - painfully over-sized!  There is a rim that sticks out from the edge which cuts into one’s eyesocket and prevents one from pressing it back far enough to block light from coming in around sides.  I wish Canon had used the better eyecups from the 12x36’s.  Neither pair comes with objective lens caps.  It was suggest to me that ordinary camera sky filters work well to protect the objective lenses.  58 and 43 mm diameter filters fit the 15x50 and 12x36’s respectively.

As for the image stabilization, the 12x36’s can easily correct for most jitter and noticeably reduces the sway introduced when one shifts back and forth on your feet.  The 15x50’s doesn’t quite correct for all the jitter and does little for sway.  Shiver in a cold wind, and you’re almost back to having no image stabilizing with the 15x50’s.

To activate the image stabilization, one must constantly hold down a button on the 12x36’s.  After a few hours of button holding, one better have a real muscle builder’s finger.  Fortunately, the button on the 15x50’s can be pressed briefly to get 5 minutes of finger-free stabilization.  In return for the finger-free stabilization, the extra weight of the 15x50’s requires muscle builder’s arms for hours of observing.

As you might imagine, both binocs depend on batteries.  Most of the time I used rechargeable alkaline batteries which usually hold up for several hours of “normal” observing (i.e., well less than 50% duty cycle).  The batteries last longer if one keeps off the button.  With nearly dead batteries, one gets a weird double vision through the 12x36’s, the stars appear one above the other.  The 15x50’s do keep trying to stabilize right up until the batteries are dead, but then one must hold the button down.  The 5 minute auto-on feature stops working when the batteries are nearly dead.

Many people have enjoyed a looksee through these binoculars.  All have been very impressed with their performance, well all but one.  A grad student at NMSU was not at all impressed by the image stabilization of the 12x36’s.  Afterwards, I spoke with him.  Since then I’ve stopped saying “press down the button” and started saying “HOLD down the button” - that helps.  Once he got the word, he was duly impressed.

Between the two, my choice is the 12x36 for their lower cost, lighter weight and better image stabilization.  The 15x50’s would come out on top if the eyecups were better and the stabilization system corrected for a wider range of shake and sway.  Given that, I’ll still probably end up taking the 15x50’s out to Hawaii in August to get the extra magnification on those southern sky objects.

Next time you’re out in the Denver area, please drop by and compare the two for yourself.  Afterall, if one pair is good, then two pairs are even better.  You are Lowbrows, and by now are ready to take out a second mortgage on your house to get yourself pair 8-))

Mark Vincent, Ph.D.  Former President of the University Lowbrow Astronomers, author of this article, and self-proclaimed “Prez-Emeritus” stands at the South Pole all set for a swim.  Is that a snorkel and are those boots or swim fins on his feet?  Mark gave a talk about his trip to the South Pole, for more details follow this link.  Mark is currently working in Colorado on a new design for a near infrared camera and preparing to go to Hawaii for his third paid vacation there. 

See also photographs from Mark Vincent.

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Copyright © 2013, the University Lowbrow Astronomers. (The University Lowbrow Astronomers are an amateur astronomy club based in Ann Arbor, Michigan).
This page originally appeared in Reflections of the University Lowbrow Astronomers (the club newsletter).
This page revised Sunday, March 9, 2014 4:30 PM.
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