Seems very expensive for a pair of binocs, but the price is clearly justified as Canon has crammed in some amazing optical wizardry in a small compact package. I will outline what makes these particular binocs so unique....1.TFOV - 6.5 Degrees.TFOV = True Field of View - in visual optics this defines how much of the scene (subject) is visible inside the image circles you view through the binocs. The greater the TFOV is, the easier to locate subjects you are seeking. (such as finding wildlife that appears in the periphery part of the image circle) To be specific, the 6.5 degrees means, if you stood in the middle of a circle, and pointed the binocs to the circles circumference, you could see a 6.5 deg. "slice of the pie". It doesn't seem like much, because we can see approx. 110 degrees with our two unaided eyes, but the binocs offer 10x magnification, which is why we see such a small piece of the pie. But on a relative basis, for binoculars of this magnification, the 10x42L's TFOV is exceptional, which also is what makes them very nice astro binocs for stargazing, as TFOV allows you to pack more stars inside the image circle.
Large TFOV requires relatively short fl's lenses which must be well corrected for abberations / distortion, and also must contain large field stops in the EP's, (Eye Pieces). Both of these optical characteristics are very difficult to design and build...this is true in all optics, not just binoculars.6.5 deg. TFOV is one of the most generous TFOV's available in ANY binocs of this magnification, even those costing several thousand dollars.This is a very impressive feature.This is one of the features that differentiates lower priced binocs from higher priced binocs., as larger TFOV requires bigger (and heavier) glass.
2.AFOV - 65 Degrees. The "Apparent Field of View" is a clear and sharp 65 degrees. AFOV defines the size of the image circles you see when looking through the binocs. This means, at 65 degrees, your eye must swing 65 degrees, left to right (or up n down) to see the entire image circle. This has NOTHING to do with TFOV, which designates the how much of the subject (slice of the pie) you see in the AFOV image circles. AFOV and TFOV is what differentiates expensive optics from lower priced optics in the same class (such as 10x30, 10x40, etc) as large AFOV / TFOV requires very expensive and complex glass elements. The other major factor is image quality.
At 65 degrees, Canon is nearing the limits of AFOV, even in very high end astronomy gear.... and probably one of the largest AFOV's for any binocs I am aware of. But Canon maintained the sharpness in the entire AFOV, with virtually no distortion! (a remarkable accomplishment in optics in this price range) The larger the AFOV, the more life-like the view becomes as it fills your retina with imagery, ridding the "looking through a tunnel feeling" that smaller AFOV create. A single unaided human eye can see 90 degrees.So at 65 degrees, you are filling 2/3rds of your retina (where an image is formed in the back of your eye) compared to unaided vision. This produces a feeling of immersion (like Imax, vs. normal movie screen), and this really adds to the WOW factor. This is the largest AFOV I have ever seen in a pair of binocs at ANY magnification.This large AFOV is the first thing that will strike you when using these binocs. Unless you venture into high end astronomy gear (costing many times these binoculars) it's hard to find find good optics with a AFOV this wide, AND, with sharpness right to the edges AND virtually NO distortion.
3.L Glass....very sharp glass, with no false color and pinpoint sharpness, nearing true APO chromatic lenses. This is very evident when viewing stars at night, the stars are pin point sharp, better than most astronomy binocs I have used.... and with the the wide TFOV and large AFOV, you feel like you are space walking into the stars while laying back on a lounge chair.Of course, with only 42mm objectives, it helps to be in a very dark site. If astro use is the primary intended use, then larger objective diameters are better suited.50 - 70mm objectives are ideal, such as the 7x50's I mention below...or if you use a tripod, then max. objective diam becomes more desirable such as 15x80 or even 20x100. So, these binocs make good astronomy binocs, but not ideal...there is better options with bigger apertures for star gazzing... it's just a nice add-on feature if your intended use is mostly daytime viewing.
Those who use high end photographic lenses know how prized Canons "L" lenses are...hence why I was surprised to see "L" glass in these binocs.
4.IS - well, this has been beaten to death, but IS is the single biggest breakthrough since binocs were invented - assuming you want to hand-hold at high magnification. Otherwise, the IS feature is not as significant.The IS in these 10x42's are superb...the "push once" IS button is a nice feature, as you don't have to continuously hold down the button while viewing. The IS has a motion sensor which sense when viewing is finished, then shut down the IS, to save battery life - nice feature. But other Canon binocs have IS, so it's not what sets the 10x42's apart from the other Canon IS binocs...But if you hand-hold, and desire at least 10x or greater magnification, IS should be your single most desirable feature in binocs.
5.Aperture(Objective Diam.) -42mm obj. diam. at 10x magnification provides very bright views, specially during mid day, and good (but not great) at twilight. They are also "just" large enough to use as astro binoculars...once you begin star gazing through these you will become interested in the night sky. Buy a good binocular astronomy book and you will be amazed. If they tried to go bigger, the weight of the binocs would become unruly, creating arm fatigue, so I feel Canon reached a good compromise at 42mm objectives. A pair of UV filters are a good idea to protect the objectives as the elements are not recessed back far enough behind the rubber front rims.(one of the few shortcomings I have found with these binocs)I have a pair of Fuji 10x70's, which the 70mm objectives, which allow almost 3x more light in....yet with the IS and pinpoint sharpness, I am quite amazed how these Canons perform considering their small objectives for astronomy binocs. I am pretty sure Canon did not design these for astro binocs. But night time viewing is very acceptable with the 42mm objectives, as they allow 2x the light vs. normal 30mm objectives,and the added light is very apparent in addedsharpness and contrast.
6)Exit Pupil diam....The exit pupil diam of any visual optic, is the diameter of the circle of light that exits the eyepiece and funnels into (or on) the eye.The diameter of the exit pupil is determined by objective lens diam. / magnification. 42/10 = 4.2mm wide. The significance of this value is how it relates to the diameter opening of your eye pupil.If the exit pupil diameter is larger than your eye pupil opening, it means several things....
a)some of the light is being wasted, as its overflowing the bounds of your eye pupil opening. This wasted light means, you are carrying heavier binocs than you need to, as the weight and size of binocs are a function of the objective lens diam.(front lenses), at a given magnification.
b)However, this extra light, provides a useful benefit, as it allows some eye placement leeway, so you don't need to be so precise in setting the binocs IPD (Inter Pupilary Distance setting) and keeping the binocs dead still.As when the exit pupil of light misses your eye pupil opening, you get that annoying "black-out" condition in that eye.This happens very often when the exit pupil of the binocs equals your eye pupil diam.
c)The larger exit pupil diam. also allows your eyes to swivel a bit inside the image circle without the black-out condition. With these 10x42's, at 4.2mm exit pupil diam., assuming you set-up the binocs precisely, you have very little leeway to swivel (rotate) your eye inside the exit pupil diam., so this forces you to keep your eyes looking at the center of the image circles, and constantly move the binocs to keep the subject of interest centered. This can be quite annoying when watching a flock of birds...vs. having a large 7mm exit pupil, where you eyes can swivel around without moving the binocs.... but, you must carry larger objective lens binocs to gain this benefit. IMO, this issues is often overlooked in selecting binocs, and if compared side by side, it is obvious how luxurious large exit pupil diameters are. Hence why it sometimes makes sense to go for a lower magnification binoc. to gain larger exit pupil diameters.
To further complicate this matter, our eye opening dilates based on the amount of light hitting the eye. For mid day viewing, most human eyes are dilated down to 2-3mm opening, regardless of age.However, as we age, our max.eye pupil opening becomes smaller....this is very significant when selecting visual optics.Next time you get an eye exam, ask what the diam. of your dark adjusted pupil is. When we are young, our eye pupil will dilate open VERY wide at night. But age is very unfriendly to the eye in this regard.Here is an approx. chart showing how our max. pupil size becomes smaller through time...
Age vs. Eye Pupil Diam. (Avg)
Age ... Day light pupil... Night light pupil (mm)
20...(4.7)....(8.0)
30...(4.3)....(7.0)
40...(3.9)....(6.0)...Read more ›
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Product Description:
The much-anticipated 10x42 L IS WP is the first waterproof binocular to incorporate Canon's exclusive Image Stabilizer technology for steady, shake-free viewing. The high quality L series optics, featuring 2 Ultra-low Dispersion (UD) lens elements (on each side), deliver excellent correction for chromatic aberration. With a large lens diameter and a 4.2mm exit pupil diameter, this binocular provides an exceptionally bright view, even in low-light conditions. The 10x42 L IS WP binocular offers both the desired brightness and excellent waterproof capabilities, making it ideal for a host of activities including marine use, stargazing and wildlife observation - just to name a few.
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