The Binocular Buyer's "Tome" (the abridged version):
Steiner 7x50's have been the benchmark/ones to beat for many, many decades. But starting in '95 or so, Fujinon essentially matched them, performance wise. And there are a lot of other contenders for the throne any more.
The biggest clincher (feature) for the title, is the percentate of light transmitted through them. With spectacular (& pricey) ones, allowing about 95% of what they take in to reach your eye.
There are plenty of good binocular reviews
which will tell you how much brand X, & model Y transmits, light wise. However, it takes at least a 5% difference for your eye to be able to notice said difference between 2 pair. And that last couple of percent tends to be EXPENSIVE.
If in doubt, Practical Sailor routinely does bino tests. Including publishing this figure, although I doubt that they actually test them themselves on the light transmission
numbers. And typically West Marine keeps many, many years of back issues of PS in their in house catalog rack (of all kinds of different equip. catalogs).
BTW, while Swarovski, not Zwarovski, makes some incredible glass. Unless they've changed their lineup in the last few years, they don't make ones with a compass & built in ranging scale. Which are kind of essential in marine binos.
The compass helps you with nav, as does the horizontal, & vertical gridded scale. They allow you to measure the height & size of things, & thus if you're getting closer or further away from them. And also, if you know their size/height, & care to do the geometry, you can figure your distance from said objects.
The compass, of course, especially with the extra magnification, lets you shoot bearings, & use them to plot your position on a chart. Old school
Or to know around where to aim the binos, based on your position, when looking for say, an aid to navigation
. Like channel markers, rock pinnacles, or a tower on land, which tells you that you're near locale X.
7x50mm is THE standard, for a couple of reasons. 7x is about the most magnification which you can reasonably hand stabilize from a vessel. And the 50mm diameter lenses, when paired with the 7x magnification, let in as much light as your pupil can (theoretically) use to discern things with, in low light.
If you have 7x, but with a smaller lens, you wont be able to see as well at dusk, dawn, when it's heavily overcast etc. Google
The Steiners, & some other marine binos are heavy, to aid with you being able to stabilize them. Though, of course, they also get heavy to hold; with your hands, or on a neck strap after a while. Your call.
Also, some of the weight depends upon what the binoculars housings are made out of. Some are aluminum
, some (like Steiners) are polycarbonate (lexan), & others are plastic, or unknown.
To try out several pair, & settle on one (or a pair), you'll need 3 things.
- A printed out copy of an optical test/resolution chart. Which is slightly different from an MD's eye chart, but...
- A piece of plywood
, 1/2" thick minimum, cut into a 2' or so diameter circle or oval.
- A baseball or tennis ball.
~ Now, paste up the chart somewhere in the store, & maybe one on a telephone pole or similar 50+yds away. And take a gander at it with your candidates.
~ Then, have them shut off 3/4 of the lights in the store, put the plywood
circle on top of the tennis ball, & step onto it with the binos Strapped around your neck. And take another gander at the optical test chart. ~ Judge Away!
*This would be a decent time to check & see if the eye pieces have diopter locks. A rarity in marine binos. At least when I last looked at them 5yrs ago.*
A few ways to see, fairly easily, the difference between cheap
glass, & quality stuff are;
- To check the crispness of what you can see through them around the edges of the lenses, when viewing things.
- Turn them around backwards, & see which pair see more clearly, & by how much.
- Turn out the lights, fully, & then try to see edge details on things.
*** The balancing on the woobly wooden circle mimics being onboard a moving boat, & the dim lighting
in the store mimics... you get the picture. ***
NOW you can more realistically see which binos work the best for you. And have the Admiral, & other crew, try'em all out as well.
Don't scoff at the test, given the $ you're dropping on the binos. As well as what getting the best pair means for you, your crew's, & your boat's safety
Try this same test with the image stabilized binos. Both with the stabilization on, & with said feature disabled. As at some point it may/will be. If via no other means than a dead battery
@ the wrong moment.
I say this, especially as stabilized binos typically have tiny lenses, relative to their 7x50mm cousins. So seeing in the dark isn't necessarily their forte. Nor is wide a field of view.
Finally, check the warranties on your top 3-5 candidates. As they can vary wildly, from brand to brand, & model to model.
Although a warranty does you little good if you K-mart, blue light specials, crap out in Bora Bora
. So choose wisely.
AKA, do your homework on the brands in question, reliabilty ratings. As well as where they have service
centers, & what you need to do, if a warranty issue does arise.
Finally, buy; a good, comfortable neck strap for the ones which you pick. And a box to mount to the bulkhead by the companionway
, to tuck them into. That, or make your own.
Also, add a retention strap for the binos to said box, regardless of who makes the box.
And buy or make, a good, hopefully padded, floating case for them. For dingy trips & the like.
That, & keep in mind that it's wise to have 2+ sets of binos on a boat, although both needn't be of the premium variety.
My backup pair are the West Marine $50 specials, which I bought 25yrs ago & was "poor", to go on my 1st boat back then. And they still work fine, but have a little bit of anodizing failure issues (where the strap attaches).
PS: Sometimes you can find pre-loved, or reconditioned Steiners & other high end bino's for $300 or less. I got my Commander Pilot-S's this way for about $400. The catch being that they only came with a 5yr warranty.
That was 17yrs ago, & they're still parked faithfully in my seabag. And even have the original (working) battery
There's more, but I'm sure you're sick of my babling by now.