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Randolph Engineering Cobalt Polarized Sunglasses Lens Review

Updated: Jul 23


Randolph Engineering makes great lenses and the AGX/Cobalt lens is arguably their best.


This lens is the same as the AGX polarized lens, with a striking blue mirror. Usually, a blue mirror will make a difference to the tint, blocking blue light and warming the view, but in this case, the mirror has no visible effect when looking through. Because of this, the review is nearly identical to the Randolph AGX.


If you would like to know how green lenses work in general, click here.

In This Review



Lens Specs

Randolph Cobalt

Technology

SkyTec™ Glass

Lens Color

Green

Mirror Color

Solid Blue

VLT

Polarized 10%, Category 3

ABBE

58

Coatings

Anti-reflective, Scratch-resistant, Oleophobic, Hydrophobic, UV, Infrared and Blue-light blocking

Material

Glass

Weight

High (relatively)

Scratch Resistance

High

Prescription Available

No

3

The glass lenses Randolph makes have clarity on par with the best lenses available. I have no distortion whatsoever.


Is it eligible for prescription?

Not in glass, and not from Randolph, but they have partners who do make prescription lenses in this color. However, they won’t be the same.


How does the lens look?


The front has a striking deep blue mirror, the nicest blue mirror I have ever seen on a sunglass. Usually, blue mirrors have a sporty and casual vibe, often at home at the beach or on the water, but this mirror is classy and dressed up.


The back has a blue shine from the anti-reflective coating. The color is grey/green, relatively closer to the blue side of the spectrum than some other green lenses on the market. The blue mirror has no effect on the lens tint, which is interesting.

Randolph Cobalt Tint

What does the view look like?


These photos are what Randolph has used to show the view. I am using the AGX lens because it is the same.


Randolph Engineering Cobalt Polarized Sunglasses
No Lens
Randolph Engineering Cobalt Polarized Sunglasses
With Lens
Randolph Engineering Cobalt Polarized Sunglasses
Split

These illustrations are accurate to me, but they are essentially the best case scenario for this lens. The water is very green and there is no significant red highlights other than the mountains. Green very much makes this view, and as you can judge from the shadows, we are facing the sun and dealing with heavy direct glare.



Randolph Engineering Cobalt Polarized Sunglasses

This photo is a better representation. The sun is behind the camera, and it's mixed conditions. Where the sun is bright and the view is green, the lens does an excellent job highlighting the greens and yellows. However, where the shadows are in the distance are darkened to the point of obscurity. Of course, the picture is not perfect and your eyes would have a much easier time adjusting the shadows than the camera, but the point remains that the Cobalt does no favors where the sun isn't strong.


Randolph Engineering Cobalt Polarized Sunglasses
No Lens
Randolph Engineering Cobalt Polarized Sunglasses
With Lens
Randolph Engineering Cobalt Polarized Sunglasses
Split

The color is close to true to world color, at least relative to any other color lens besides grey. The greens are relatively boosted but only feel bright when the sun is strong. Reds are not highlighted and blues are cool but prominent.


Sunny Conditions

The marketing for this lens is accurate: it really is a relaxing and soothing tint, while still providing some color-enhancing effects over what a grey lens would have. For that reason, the Cobalt thrives in full sunlight, where contrast is already strong and the low VLT can make the view more comfortable without darkening too much. This lens doesn’t add much contrast or color, but does a good job managing high color and contrast environments. The blue light blocking isn't that noticeable, but it doesn't remove some haze. Since it’s best in very bright light it’s also recommended to have them polarized.


Cloudy Conditions

For the reasons listed above, this lens isn’t great in cloudy or mixed conditions. The low VLT combined with the dulling impact of the bluer green make the view dark and dull. A gloomy day can become downright depressing.

What views is it good and bad for?

The Cobalt is best for green environments when keeping the greens boosted is desired, or for red environments like dry or desert conditions when the reds are too much. I enjoy this lens driving in the northeast summer in full sun, or in Arizona when I go for work.

I rarely wear this lens in the winter, since there are little greens to boost and I’m looking at increasing contrast and color, something this lens doesn’t do much of. It’s fine at the beach but not as good as other lenses that manage to bring out the blues in the sky and water. The exception to that is when the water is very green for various reasons, then this lens is very pleasant.


I wouldn't recommend this lens for sports (especially because it's glass). If you live in an area that gets lots of clear sunlight this will work well for you, but if much of the year is winter or mixed conditions you may want to choose another lens in addition to Cobalt.


How the lens is marketed


The lens is described by Randolph as "A high-performance lens with a 'relaxing' green base, selectively highlighting soothing green/yellow wavelengths, with a subtle deep blue iridescent mirror." The AGX is described as "This ‘relaxing’ green lens selectively highlights the soothing green/yellow wavelengths of the light spectrum to reduce eye fatigue and improve visual performance."


Randolph claims in a blog post "AGX lenses are ideal for long term use because of the reduced eye fatigue and continual sharpness in vision. AGX lenses are also perfect for those who are light sensitive or prefer their sunglasses to have a darker tint. AGX lenses perform well in both clear blue skies to overcast and cloudy conditions. They are also an excellent lens for winter driving."


Randolph also says: Recommended Use: Driving, Beach, Boating, Fishing, Hiking, Aviation, Golf.

Is the brand’s marketing accurate?


Mostly. The lenses are indeed relaxing on on bright days. They work well at the beach, driving, and any other sunny condition environment. However, they would not be my first choice for golfing, as the green would be brightened and harder to tell apart. Golf requires the greens to be detailed, and for that reds need to be boosted, in bright conditions. The Cobalt is also not excellent for winter, where it feels very dark and drab. This lens is very much a cooling full sun lens.


Comparison to same brand - Randolph


The only other Randolph lenses that are worth comparing to the Cobalt (other than AGX which is the same, just without the mirror) are the American Grey and American Tan lenses, as those are Randolph's other main lenses. Any other lenses will get their own comparisons on their reviews.


The American Grey is almost as pure a grey lens as you can find. It is slightly brighter than the Cobalt at 15% VLT and no colors are boosted. In general, in pure sunlight conditions I prefer the more comfortable Cobalt and in mixed conditions, I do not like wearing either green or grey lenses.


American Tan is a reddish brown lens that has a low VLT (11%) while still adding significant contrast. In full sun it works, though feels much too hot in comparison to the Cobalt. The Tan performs only average in overcast conditions, thriving in bright haze or mostly sunny with passing clouds.


In my opinion, of the main lenses Randolph offers the Cobalt/AGX is the best choice.


Comparison to same color of different brands


Now let's briefly compare to several other brands, though each will get a more detailed comparison separately. I am only comparing to other green lenses, as the Cobalt has the same lens view as the AGX. For alternative blue mirror lenses, I will make a separate post.


Ray Ban G15

Very similar to Coblat with slightly higher VLT, so slightly less comfortable in full sun. The lack of blue light blocking is only noticeable when looking for it. Randolph does have better coatings though.



Serengeti 555nm

Compared to Serengeti 555 the Cobalt is a lot more grey/blue and "calm"; putting Serengeti 555 lenses on after wearing the Cobalt feels like someone turned the contrast and color saturation right up.



Revo Smokey Green

This lens is nearly identical to the Cobalt, and the differences are very hard to discern. The Revo is slightly more comfortable in direct sun and the Cobalt has slightly better color rendering, but it's really splitting hairs.



Persol Green

A slightly more grey lens than the Cobalt. If you do not like grey but green is too much, it is a good in-between choice. Green is rarely too much though, as the same conditions the Persol excels in the Cobalt performs just as well if not better.



Conclusion: Randolph Engineering Cobalt Sunglasses - Should you buy it?

The Cobalt is an excellent lens to look through and look at. I wear this lens mostly when I want to wear Randolph frames, which have their own good reasons for wearing. For similar frame-centric brands, it is more about looking cool than enjoying the view, but with Randolph, they didn't skimp on the lens quality even though the main draw is their fantastic frames. The Cobalt is also one of the best blue mirrors aesthetically, and I find myself wearing it more than the AGX just because of the look, though the AGX is my choice when I need to be more dressed up and mirrored lenses won't work. So, if you are set on buying Randolph, an excellent choice overall, the Cobalt is arguably the best lens you could choose from, from both a functional and aesthetic perspective.





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