Opticron Oregon 4 PC Oasis 10X42 monocular review

There is an instant feel of quality in the rugged and easy-to-use Opticron Oregon 4 PC Oasis 10X42 monocular, and thanks to nitrogen-purging it is also fogproof.

Opticron Oregon 4 PC Oasis 10x42 in front of foliage
(Image: © Matt Morris)

Space Verdict

The Opticron Oregon 4 PC Oasis 10X42 monocular is a very capable, easy-to-use monocular that instantly lends itself to rapid one-handed use. A tough rubber exterior, with good low light capability, makes this a quality monocular.


  • +

    Quality rugged design

  • +

    Ease of use

  • +

    Nitrogen-filled waterproof construction

  • +

    Close focus to 1.8 m / 5.9 ft


  • -

    Slightly heavier than some rivals

  • -

    The larger lens cover has a short strap

  • -

    The neck strap could be longer

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The Opticron Oregon 4 PC Oasis 10x42 monocular has a roof prism design with BaK-4 fully-coated optics. All of these features combine to make the mono work well in low light conditions, with excellent visual clarity. Weighing 334 g means the Opticron 10x42 is not the lightest in its class, but we preferred the additional weight when handling it because it feels sturdy.

While testing, we took a trip to several locations to test out the optics and build quality of the monocular. At a local nature reserve the Opticron 4 PC Oasis 10x42 performed incredibly well. The large external wheel focusing became one of the real strong points of the design of this unit, as it enables easy, one-handed operation enabling quick focusing on birds in flight.

Most nature and bird hides are already equipped with a shelf or viewing platform on which to place small monopods and tripods and we found it especially useful for holding the monocular, without the need for additional equipment. Dramatically reducing shake and wobble we felt confident the 10x magnification of the monocular is well suited to those, even with arm and hand trembles.

We were also surprised at its ability to perform well in low light when observing inside a cathedral. Its waterproofness was also ideal while wildlife spotting at the local allotment, conveniently hanging it up on the fence post between uses without the need to put it away. So much so that we name it as one of the best monoculars in our buying guide.

Opticron Oregon 4 PC Oasis 10X42 monocular review

Opticron Oregon 4 PC Oasis 10X42: Design


Opticron Oregon 4 PC Oasis 10x42 on a wooden table

The Oregon 4 next to its carry pouch shows just how neat and well-built this monocular is. (Image credit: Matt Morris)
  • Roof prism design 
  • BaK-4 fully coated optics
  • Nitrogen-filled waterproof construction

As mentioned, the Oregon 4 is a well-constructed, solid unit with a rubber casing and an external focus wheel. It has BaK-4 glass and phase-corrected prism coatings, which denote an extra level of quality above the more generic BK-7 glass normally featured in devices at this price point, as well as phase-corrected layers applied to all air-to-glass surfaces., Internally, the prisms are covered with phase-corrected coatings with Opticron’s Oasis high light transmission coating. All these features add up to a competent, quality feel and made us want to use the monocular.

At this magnification, there is little problem with movement brought about through vibration or unsteady hands, but it's worth noting that there are no fixings for a monopod. So observers will have to steady themselves (or the monocular, or both) on a nearby surface (like a shelf in a bird hide) or lean against something solid, like a wall, fence post or empty tripod.

Opticron Oregon 4 PC Oasis 10x42 in use in bird hide

The Oregon 4 is only 340 g, therefore it is very comfortable to use with one hand. (Image credit: Matt Morris)

Design: Roof prism

Magnification: 10x

Objective lenses: 42mm

Exit pupil: 2.5mm

Eye relief: 18 mm

Weight: 11.8 oz / 334 g

Dimensions: 5.8 x 2.9 x 2-in / 147 x 74 x 52 mm

Durability: Waterproof and fogproof

The neck strap is made of a tough nylon material with padding on the neck area which is suitable for travel. However, it's shorter than we would like, as we found hanging the device over a shoulder and the neck much better for climbing over styles when hiking. This stopped the unit from hitting our body again when it swung around us as we maneuvered ourselves. For those that can use it the monocular also ships with a carry case that features a belt hoop to prevent this problem.

Opticron Oregon 4 PC Oasis 10X42: Performance


Opticron Oregon 4 PC Oasis 10x42 in use in bird hide

Stabilizing the monocular on a shelf or open window in a bird hide helps observations. (Image credit: Matt Morris)
  • Excellent light-gathering ability
  • Sharp optics thanks to superior glass quality
  • Close focusing down to 1.8 m / 5.9 ft

The Oregon 4 is an easy-to-use, extremely capable and convenient monocular. The large external focusing wheel and the reassuring heft made it very pleasant to use whilst at our local bird hide. In fact, we found ourselves just popping it in our pockets on regular days out. This was especially helpful when visiting historic churches as we were easily able to spot details on gargoyles and other features on the buildings when outside. Its low light capability makes using it inside the dark buildings a breeze also. 

The rubber casing on the Oregon 4 feels solid and comfortably envelopes any potentially fragile areas of the monocular and the grip it provides makes it feel very secure in the hand. We’re confident it could withstand a few knocks and drops and still be in one piece by the end of the day (making it suitable to use as a family monocular, or to hand over to children who may have poorer proprioception and fine motor control).

Opticron Oregon 4 PC Oasis 10x42 in use in bird hide

The eyepiece is comfortable and provides good support when observing. (Image credit: Matt Morris)

Unfortunately, we did find the shoulder strap rather short when traveling with it. Also, the larger of the two lens covers is attached by a short cord, too short in our opinion, and can ride up and obscure views when in use. This isn’t a dealbreaker because it's easy to push back out of the way, but it kept happening and was quite annoying by the end of our time with the device.

Opticron Oregon 4 PC Oasis 10X42: Functionality


Opticron Oregon 4 PC Oasis 10x42 in use in bird hide

The larger lens cap can ride up during use and get in the way. (Image credit: Matt Morris)
  • Non-slip rubber armor
  • Objective lens cap attachment cord is too short
  • Heavier than some other monoculars in its class

The Opticron Oregon 4 Oasis 10x42 monocular is perfect for throwing in your pocket and going for a hike but we found it is also suitable for some serious hide birdwatching. It is well balanced, providing enough power to use for distant subjects whilst simultaneously being easy enough to use at the side of a football pitch to watch sports. Its waterproof and rugged design gave us the confidence to just get on and use it rather than overly worrying about dropping it or using it in the rain.

Its close focusing ability lends itself to relaxed armchair garden birdwatching. We set ourselves up on a lounger in the garden and had a bird table only a few feet away. Soon after we were able to see some great detail on the winged visitors. The low light clarity again stood out to us whilst doing this as we were able to view the birds in twilight as we moved into sunrise without too much loss of clarity.

Opticron Oregon 4 PC Oasis 10x42 in front of foliage

Good build quality and its close-focusing ability means it's useful in a wide range of applications. (Image credit: Matt Morris)

The Opticron Oregon 4 also comes with a strap-mounted chest bag/pouch which is suitable enough but its quality is commensurate with its price. The unit is built so well that this bag is purely for carrying and offers no real protection from being dropped or from the weather. 

If you’re looking for a monocular that can keep up with you in any situation and you can leave out in any weather then the Oregon 4 is a model we’d recommend. We took the Oregon 4 with us while working at the local allotment and hung it from a nearby post to grab whenever we saw something of interest in the fields around us. It was perfect for this as we could leave it outside in the rain and wind knowing that, due to its excellent build quality and waterproofing, it wouldn't be affected by the changing weather, unlike this observer!

Should you buy the Opticron Oregon 4 PC Oasis 10X42?

Buy it if:

You want affordable quality: It is priced well for its class and performs great in most situations.

Simple operation is important: One focusing wheel and lens caps are easy to navigate with one hand.

Don't buy it if:

You need the best: There are better monoculars out there, but they are more costly.

Small details irritate you: The lens cap and monocular straps are both a little on the small side for us.

In all the situations we used the Oregon 4 it performed fantastically well. If you are looking for a monocular that is reasonably priced, yet still delivers good-quality views, then this is the model for you. It has sharp optics, is good in low light and has a rugged construction, enabling it to cope with most situations. It's very easy to use and the external focusing wheel makes spotting those elusive, quick-moving subjects easy, even with sturdy gloves.

If the Opticron Oregon 4 PC Oasis 10X42 isn't for you

If the small drawbacks to weight and strap length that we’ve mentioned in this review is enough to deter you when we would recommend you take a look at the

Opticron Explorer WA ED-R 10x42. It is lighter than the Oregon 4 PC Oasis 10x42 at 320g (about the weight of an adult Black-capped Chickadee) but is a little more expensive.

At the more premium end of the scale, we think the Bushnell Legend Ultra 10x42 monocular is worth taking a look at. Almost twice the price of the Oregon 4, the Bushnell Legend Ultra has the same 10x magnification and 42mm objective lens but also includes a tripod attachment and hydrophobic coatings.

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Matt Morris
Contributing writer

Matt Morris is a keen astronomer, wildlife watcher and photographer living in Somerset, UK. He started stargazing and birdwatching at the age of 10 with his father who took him to bird hides and nature reserves around England. This sparked his interest in cameras and optics, a passion that has now spanned the better part of four decades and led to his being featured in several national photography magazines for competition-winning photos.

With contributions from