Product Review: Vortex Diamondback HD 10 x 42.

The Vortex Diamondback HD 10 x 42 package.

A Work Commenced January 31 2022

Preamble 1

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Preamble 3


Product: Vortex Diamondback HD 10 x 42

Country of Manufacture: China

Chassis: Rubber Armoured Magnesium Composite

Exit Pupil: 4.2mm

Eye Relief: 15mm

Field of View: 110m@1000m(6.3 angular degrees)

Coatings: Fully Broadband Multi-coated, phase correction and dielectric coatings on BaK4 prisms, Armortec anti-scratch coatings applied to outer lenses.

Dioptre Compensation: +/- 5

Close Focus: 1.52m advertised, 2.21m advertised

Water Proof: Yes

Argon Purged: Yes

ED Glass: Unknown.

Weight: 605g advertised, 608g measured

Dimensions H/W 14.5/13.0cm

Supplied Accessories: Padded neck strap, Glasspak binocular harness, tethered rubberised objective and rain guard, microfibre cloth,  instruction sheet, VIP Warranty

Price(UK): £229.00


Vortex, a US-based company founded in 2002 in Middleton, Wisconsin, has grown to become one of the leading manufacturers of good but economically priced binoculars for the growing sports optics industry. Today they sell an impressive range of binoculars, monoculars, spotting scopes, rangefinders, riflescopes and other products, mainly for the American market, but have also made very solid inroads here in Europe. Arguably their best-selling product is their highly popular Diamondback binocular range, which first came to market in the early noughties, but has underwent a number of upgrades over the years. The second generation Diamondbacks came out in 2016, and mainly involved improvements in the ergonomics of the chassis. Then in 2019, a third generation of the Diamondback series was introduced. This time, no changes were made to the ergonomic features of the binocular, but the optics received an upgrade to so-called HD status, which promised better colour correction, contrast and edge of field performance. The Diamondback HD series offers an extensive range of binoculars in apertures all the way from 28mm right up to 56mm. This review will concentrate on the 10 x 42 HD, particularly popular with birders and hunters.

First Impressions

The package arrived in a single box, housing the binoculars, the Glasspak case and strap, lens cleaning cloth, padded logoed neck strap, an instruction card and VIP warranty information. The binocular was presented with its rain guard and tethered objective covers attached.

Examining the binocular, I was quite impressed with its streamlined appearance and robust build quality. The magnesium composite chassis is overlaid by a tough green rubber armouring, textured on the sides for extra grip.

The twist-up eye cups worked perfectly from the get go, and the central focussing wheel rotated smoothly without any free play. The central hinge was quite stiff out of the box and held my personal IPD very well over a few weeks of testing. The right eye dioptre turned only with a fair amount of effort – a good thing surely. Overall, the cosmetic appearance of the instrument was flawless. So far so very good.


The Vortex Diamondback HD 10x 42 is a smart, solidly built binocular.

From the moment I first help the Diamondback HD 10 x 42 in my hands, I got the distinct impression of quality. This is a well designed and refined binocular, and it shows. Everything is mature and well thought through. The eye cups are made from a very tough rubber substrate, which have three positions to suit various eye placements, with and without glasses. They twist up with one intermediary position, and a loud click tells you they are rigidly in place. Nice engineering!

The textured rubber armouring on the side of the Diamondback HD affords excellent gripping.

I found no issues seeing the entire field of view without glasses and the eye cups fully extended outwards. I did however have a bit of an issue seeing the entire field when I retracted them using eye glasses, but you could get there with a squeeze… but only just. In use, I sometimes got the impression that they were a tad too hard when pushed up against my eyes, but it wasn’t a big deal in field use.

The focus wheel is very nicely engineered and provides smooth accurate focusing. The eye cups lock very rigidly in place in all settings.

The focus wheel rotates very smoothly and accurately, with a a nice amount of traction. It is neither too fast or too slow. I suspect many users will find it just fine. From one end of focus travel to the other takes just 1.5 turns. The dioptre ring, which is located under the right ocular, has an acceptable amount of tension so that one needn’t worry that it will slip out of position easily. A prominently visible, white line indicates your correct setting and small but distinctly visible dots on either side presumably indicate plus and minus settings, though it’s not clear which is which until you dial in your preferred setting.

The underside of the binocular has two prominent thumb indents. While many users might find them useful, I found that my own thumbs didn’t naturally rest there to obtain the most stable handheld views.

The underside of the Diamondback HD 10 x 42 has thumb indents but I never used them while holding the binocular.

The objectives are not very deeply recessed as mid-sized binoculars come. I suspect this was a design compromise to shave off as much weight as possible from the binocular in order to maximise its portability. But in my experience, this only increases the chances of picking up glare in field use. More on this later. On the plus side though, the Diamondback HD 10 x 42 tips the scales at just over 600g – a remarkable fact! Indeed, it is much lighter than the vast majority of binoculars in this size class.

The internal optics are argon purged and O-ring sealed. Why argon? Well, its an inexpensive noble gas, so is completely unreactive. One other bonus is its larger relative atomic mass than molecular nitrogen (40 as opposed to 28). In theory this should decrease the rate of diffusion of the gas from the interior of the binocular, but I’m not sure whether it makes much difference to nitrogen in the scheme of things.

The objectives on the Diamondback HD are not very deeply recessed.

Overall, I was very pleased with its sleek, ergonomic design. A lot of thought was put into this binocular and it’s abundantly in evidence!


As always, I began my optical testing to see how an intensely bright beam of light  behaved as it was directed through the binocular across a room. The results were excellent, with no significant internal reflections detected. Neither was there any annoying diffraction spikes or diffused light around the beam. This indicated that the coatings applied to the lenses and prisms were of high quality. Indeed it was pretty much the equal of my control binocular – the Barr & Stroud Series 5 8 x 42 ED – in this regard. The same results were in evidence when I turned the binocular on a sodium street lamp at night.

Next I took a look at the exit pupil from both barrels of the binocular. Both the left and right barrels had round exit pupils, and little in the way of stray light around them as shown below.

Left eye pupil.

Right eye pupil.

My first look through the binocular on a dull overcast winter day proved very promising. The Diamondback HD 10 x 42 threw up a very good image, with a big sweet spot within which the image was very sharp. Contrast and colour fidelity were also very good. I detected the merest trace of chromatic aberration in the centre of the image which became progressively more prominent when the targets were moved off axis, but overall I judged the colour correction to be very good. Edge of field sharpness fell off a bit, starting from about 65 per cent out from the centre of the field.

As an astronomer, I’ve learned that the best way to test binocular aberrations is not during daylight observations, but under the night sky. Rising before the Sun on a late January morning showed a last quarter Moon to be nice and sharp within the sweet spot, with very little colour fringing at the limbs. Moving the Moon off axis showed up more lateral colour and some drop off in illumination, as the bright, silvery orb was brought progressively closer to the edge. Right at the edge of the field, the lunar image became darker and a bit fuzzy. I was able to refocus it to some degree, but was unable to obtain a perfectly sharp image. The same was true when I turned the Diamondback HD 10 x 42 on some bright winter stars like Capella and Procyon. Stars remained crisp and tightly focused out to about 65 per cent of the distance from the centre, before significant distortions began to creep in. Stars placed at the edge of the field could be improved somewhat by re-focussing but not entirely so, indicating that field curvature was not the only geometrical aberration in evidence, with astigmatism being the most likely culprit.

Collimation was shown to be quite excellent in the Diamondback HD however, as evidenced by seeing a perfectly focused star at the centre of a defocused diffraction disk, evinced by rotating the right eye dioptre ring to the extreme of its travel.

The Diamondback HD 10 x 42 did throw up some glare though. While looking towards a setting Sun behind some thin clouds, the field became a bit washed out. Veiling glare was also in evidence as a bright arc of light at the bottom of the field when I pointed the binocular high up into the canopy of some conifer trees against a bright overcast sky. And while shielding the objectives with an outstretched hand removed a lot of this unwanted glare, it couldn’t remove all of it, unlike with my Leica Ultravid 8 x 20. I believe this could be significantly improved by recessing the objectives more deeply than they are.

Notes from the Field

Despite these shortfalls, some time out in the field with the Vortex Diamondback HD 10 x 42 convinced me that this is a good, solid performing binocular, with no serious defects. The images it throws up are impressive but are certainly a notch down on higher quality instruments, such as my GPO Passion ED 10 x 32, which I found to deliver better contrast, sharpness and more vivid colours than the Diamondback, and with less glare to boot. Close focus was measured to be 2.21m, considerably more than the advertised value of 1.52m.

One very pleasant aspect of using the Diamondback HD 10 x 42 was its low weight. In my opinion, its low mass really adds to its ergonomic appeal. A lighter weight binocular like this is often easier to stabilise and easier to use, especially in prolonged excursions.

Its excellent collimation also reduces eye fatigue .

Conclusions & Recommendations

The Diamondback HD 10 x 42 is a very good binocular that serves up impressive images, with no serious optical defects. It does many things very well, but falls short of being considered outstanding. It’s a pleasure to use in the field, with a tough, lightweight chassis, excellent twist-up eyecups and a well-designed focus wheel. While it is unlikely to impress those used to looking through substantially more expensive models, it will certainly deliver the readies for most applications. And when you factor in its modest cost and VIP warranty, I believe it offers a lot of bang for the buck, making it easy to see why it remains a very popular choice for nature lovers, hunters, birders and stargazers alike.



Dr Neil English is the author of a 650+ page treatise, Chronicling the Golden Age of Astronomy, celebrating the lives of dozens of astronomers over the last four centuries, who turned their telescopes towards the heavens in search of celestial treasures.



De Fideli.

9 thoughts on “Product Review: Vortex Diamondback HD 10 x 42.

  1. Excellent detailed review
    Full of info but not boring.
    Very useful.
    I bought one of these about a week ago before I came accross your article and I totally agree with your conclusion!
    Good work. Thank you!

  2. Hello Raoul,

    Thanks very much for the feedback.

    Gotta love those Diamondback HDs!

    Best wishes,


  3. Verify nice thorough article. You certainly give us a well thought out review as opposed to the flashy non informative ones that I am used to. I to bought these binos and am well impressed. The weight was the deciding factor for me.


  4. Hello Alex,

    Thanks for your kind words and feedback. I thought the 10x 42 Diamondback HD was rather quirky too. A great bargain in today’s market.

    Best wishes,


  5. Hi, A really useful review with which I fully agree. I have a pair of these and they have served me well until the rh eyepiece dropped off and was lost. Replacing this has been impossible so far. Any tips? The US website for Vortex will not accept my address so no joy there.

  6. Hello Moya,

    So sorry to hear that. It shouldn’t really happen as Vortex has a VIP warranty.

    Can you send them a receipt or an email confirming your purchase?

    I’m sure if you are patient but persistent they will honour it.



  7. Alex, your review was very well constructed and you have presented the information in a very relateable manner. Thank you. I feel much more informed on the reality of how good they are.

  8. I bought the Vortex DB 10×42 for its low weight, because of a very attractive promotional price, and because I was pleased with my Vortex DB 8×32. I agree with this review. But in comparing any 10×32, even Neil’s GPO, to a 10×42, I suggest that the relative ease of eye placement, in my experience, of the handy DB 10×42, should also be mentioned.

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