Binoculars are one of those things that people find really fun
and cool, but sometimes don’t know what to do with. Or what all the numbers
mean. Or what all the weird terms are. Why do I even need these?
Well, for certain kinds of photography they can be
incredibly important. For example, if you want to take pictures of wildlife,
you have to find it first and binoculars can help with that.
First, let’s dissolve some of the confusion and give you a
clear view of why these gadgets are so handy.
What’s with the numbers?
When looking at binoculars, you’ll notice there’s numbers everywhere like they’re supposed
to mean something. Well, they do.
These numbers, like 8 x 42 or 10 x 50, aren’t just multiplication. They represent the
amount of magnification the binocular provides and the diameter of the front
objective lens which is responsible for gathering light.
Magnification x Objective
Lens Diameter - So for 8 x 42 binoculars, you know you’re getting 8x magnification,
with a 42mm objective lens to capture light and transmit the scene to your
little eyeballs.
Obviously, a larger objective lens can gather more light,
meaning you’re able to view a brighter image. But bigger doesn’t always mean
better. Remember, you have to carry these things around.
Great, got it. Now what?
Now we’ll get into a
few other terms you might encounter when searching for the perfect pair of binos.
Yes, there’s more than just magnification and objectives, so strap in for a
quick breakdown.
Field of View –
Exactly what it sounds like. It’s how much of the scene you can see when
looking into the eyepieces.
It’s good to note that as the magnification increases, the
field of view decreases, so going with high magnification isn’t the be-all and
end-all.
If your main use will be general viewing or spotting good locations
and wildlife, having a wider field of view is ideal. It’s also better for
tracking faster-moving animals which are
challenging enough to catch in the first place.
We’ve
all noticed this little bright dot when we hold up a pair of binoculars.
Exit Pupil – A
virtual aperture that light passes through to reach your eyes. Just like a lens
with a camera. Except in this scenario, the camera is your head.
If you’ve ever held a pair of binoculars away from your
face, you’ve probably noticed a little bright dot in the eyepieces. That’s the
exit pupil and yes, there’s maths to calculate its size.
Objective Lens
Diameter ÷ Magnification
Example: 8 x 42
binoculars would be 42 ÷ 8 = 5.25mm exit pupil.
Cool, why does this matter? Well, just like some lenses are
better in low light, the same is true for binoculars. Wider exit pupils send
more light to your eyes which is better in dim lighting. It isn’t as much of a
factor for daytime use, but at dawn or dusk, a larger exit pupil will help.
Pretty
easy to spot the difference between Porro prism binoculars (left) and a pair
with roof prisms (right).
Prism Type –Binocular
optics use either roof or Porro prisms.
Usually, you can tell by how they look; if the eyepieces and objectives lenses
are in a straight line, they’re roof prisms. If the objectives are wide-set and
not aligned with the eyepieces, the binoculars are Porro prism based.
In the past, Porro
prisms were the way to go for image quality as they could reflect more light
and provide a much clearer, brighter image. Their design, however, makes them a
bit heftier, so they’re not always the most portable option.
Roof prisms are positioned in parallel with the lenses and
eyepieces, meaning the body size can be more compact. The downside of this
style was that it used to reflect less light, so image quality wasn’t the
brightest.
Nowadays, the choice mostly comes down to cost. With the
introduction of lighter weight materials and more reflective prism coatings,
both styles can perform similarly. If you’re looking to save a few bucks
without compromising on image, grab a pair
of Porros and for portability, look into
some good roof prism based models.
Phase Shift – This
applies to roof prism binoculars. If you’re leaning toward this style, make
sure you look for phase correction coatings.
When light enters the optics and reflects off the prism’s
multiple surfaces, the light becomes partially polarised and splits into two misaligned
beams.
Without corrective coatings, overall image quality will
suffer from lower contrast and clarity, so you definitely want to make sure
your chosen pair has the right coatings for a better and more accurate viewing
experience.
Image Stabilisation
(IS) – Some binoculars have image stabilisation to minimise the appearance of shakiness and movement. This
is a really great feature if they’re going to be used every day for critical
viewing applications, like rescue spotting or even just to help reduce fatigue.
Of course, some binoculars have a tripod thread, but if
you’d rather go handheld, IS will make a world of difference.
If you’re planning to go down this route, Canon has some of
the best options available. We were
lucky enough to get our hands on some and let me tell you, we spent a lot of
time peering out our office windows and whispering “Wow…” when the stabilisation kicked in.
In the above video, you can clearly see the huge difference it
makes. Both the view and movement get much smoother and easier to track. The
subject, on the other hand… kinda suspicious looking.
To understanding what is happening internally with image stabilisation, Canon have put together this demonstration video of the moving parts inside of one of its binoculars.
To understanding what is happening internally with image stabilisation, Canon have put together this demonstration video of the moving parts inside of one of its binoculars.
And now, young grasshopper, you’re ready
You may have noticed a common theme in the above terms and features.
Much like cameras, some binoculars are more suited to certain applications than
others. Choosing the right pair depends quite heavily on what your primary use
will be, so it’s important to determine that before buying.
A compact pair of roof prism binoculars, 8 x 32 or 8 x 40, is
a reasonable starting point for the casual observer. These are easily portable
and can be found more cost effectively while still offering a good amount of
light transmission, magnification, and field of view.
There are more purpose-built options out there, but that
depends on you. Binoculars aren’t a requirement for any kind of photography,
but they can sure as heck make it a lot easier to suss out good shooting
locations or track and spot photogenic wildlife.
Hot tip for all you astro-photographers out there! Binoculars make a great celestial object spotting tool.
A photographer’s arsenal can seem endless, but once you make
the jump towards a certain style, you start finding the little things that can
make a big difference to your images.
Hopefully this has helped demystify binoculars a little bit and given you a few reasons to think about getting some for yourself!
If you’re up for more binocular chat and tips, give us a shout on our social media channels!
Hopefully this has helped demystify binoculars a little bit and given you a few reasons to think about getting some for yourself!
If you’re up for more binocular chat and tips, give us a shout on our social media channels!
