Zeal Optics Auto Sun Sunglasses Lens Review
- Sunglass Science
- 30 minutes ago
- 7 min read
The Zeal Auto Sun is one of the more unique sunglass lenses on the market. It combines photochromic technology with polarization and a color-shifting tint that adapts to changing light. In this review, I’ll break down how it works, what it’s good at, and who it actually makes sense for.
Check out the Auto Sun lens from Zeal Optics Website.
If you want to know more about how brown lenses work, click here.
If you want to know more about how yellow lenses work, click here.
In This Review
Lens Specs | Zeal Optics Auto Sun |
Technology | Ellume |
Lens Color | Yellow/Brown |
Mirror Color | N/A |
VLT | 28-15% |
ABBE | 30 |
Coatings | Anti-reflective, Scratch-resistant, Oleophobic, Hydrophobic |
Material | Polycarbonate |
Weight | Light |
Scratch Resistance | Moderate |
Prescription Available | No |
3 |
The clarity of the Auto Sun lens is average. The lens material is polycarbonate, which is very good for impact resistance. It is the only non-prescription Zeal lens that has an anti-reflective coating, and that makes a noticeable positive difference for clarity.
In addition to anti-reflection coating, the lens also has scratch-resistant, oleophobic (oil-resistant), and hydrophobic (water-repellant) coatings. This makes the lens more durable and easier to clean.
The lens changes from a category 2, 28% VLT light yellow tint to a category 3, 15%. Zeal calls the dark tint "persimmon", but just think of it as brown or copper. It is a very unique lens in that it changes color and not just tint level (how dark it is). I can think of only a handful of lenses that do that. This is also the only yellow-to-brown lens that I know of.
The lens changes from light to dark in around 60 seconds.
Zeal is owned by Maui Jim and has access to the same high-quality polarized filters (all Zeal lenses are polarized) and a version of the color-enhancement technology that Maui Jim uses, just adapted for their own lenses.
Is it eligible for prescription?
No. Go to SportRx for all your Zeal prescription needs. Use code SCIENCE10 at SportRx for $10 off your order.
Also check out: Best Sunglasses Cases, Storage, and Travel Cases
How does the lens look?
The front has no mirror. When the lens is not activated, it is a light yellow, and the eyes are slightly visible to a viewer. When darkened, it is like a regular brown lens in that it looks essentially black.
The back has a yellow shine from the anti-reflective coating. I held a towel over the right side and held the left side in direct sunlight for a few minutes, then took this photo within 10 seconds of leaving the sun.
What does the view look like?
As this lens changes color and darkness, there are two parts to this.
When the lens is yellow and at its brightest, the character of the lens leans more towards function than aesthetics. What I mean by that is that yellow lenses are not particularly pleasing to look through for most people, because they remove nearly all blue light and make the view distorted relative to how we are used to seeing color.
The function part is that yellow lenses increase spatial contrast. That means helping you see the difference in brightness between objects and settings, rather than the difference between colors. Yellow lenses reduce atmospheric scatter by filtering much of the blue light responsible for haze and washed-out lighting. With less visual noise, edges defined by light and dark become easier to see, even though color accuracy decreases.
In flat lighting, where color information is already limited, a stronger separation between objects and their background can make movement easier to detect.
That is why the light yellow stage is for low light. I would specify low flat lighting, like foggy, grey, or winter conditions, as colorful low light would not work as well with this lens.
This is important to keep in mind for driving. Since a windshield blocks most UV light, the Auto Sun will not adjust behind it and will stay light yellow. This can help with driving in flat conditions, and I wear it for foggy or winter driving often. But when the sun comes out, this lens will not only be too bright, it will also be yellow and make for a distorted color view.
When the lens does change to its darkened brown state, it gets comfortably dark but not too dark. 15% is an average VLT, not ideal for something like offshore fishing, but perfectly fine for most standard activities like hiking and walking in and out of stores.
Sunny and Coudy Conditions
These photos are what I have used to show the view. Keep in mind that photos will never look as good as the real view looking through the sunglasses with your own eyes.
Interested in experiencing the lens for yourself? Check out the Auto Sun from Zeal.
Here is my simulation of how the lens looks:
In low and flat lighting, where the sun doesn't necessarily make you squint, but you would gladly make it slightly darker in exchange for added color, clarity, and contrast, the Auto Sun performs well. The yellow tint isn't the most aesthetically pleasing, but it adds clarity in a way that also feels brighter because of the increased spatial contrast from the yellow tint.
Where this lens lags in a car. The lens needs UV light to change tint, and windshileds block most UV light. This means the lens will stay in its lighter VLT yellow state, which is a bit jarring and not comfortable in full sun conditions.
In contrast, a grey polarized lens will be much more comfortable and natural in these conditons. Something to keep in mind, and you will likely want another lens for the car. That being said, it still works well for driving in flat light or winter conditions.
When not in a car, the Auto Sun performs well in sunny conditions. The picture below also has some thin clouds and haze, which is even better for the Auto Sun. The 15% VLT in its darkened state is enough to be comfortable without being too dark. The color is a redder/oranger brown that makes the view warmer and more energetic.
Optimal and Suboptimal Viewing Conditions
The Auto Sun is a versatile lens that performs well in most situations. In lower light I often prefer other color tints to yellow, but there's no denying that it works in a functional sense, even if it doesn't look the nicest. In full sun or bright overcast, it is essentially a regular, well-done brown lens.
As mentioned above, it won't work well for most driving. It is just fine in winter, with the yellow working well in low light and the brown not as good as rose in bright sun, but better than grey or green.
This lens will often not be the best possible lens for any given situation, but it won't be far off. If you only want one contrast lens to complement a grey or green lens, this could be a great choice.
Sports
As a fully coated poly lens with photochromic properties and warm tints, the Auto Sun works well for nearly any sport, as long as you don't mind having a polarized lens for it.
Comparison to the same brand - Zeal
Ellume Polarized Copper
The Ellume Polarized Copper lens is a 14% VLT brown/copper lens. It has anti-scratch coating, but does not have anti-reflective, hydrophobic, or oleophobic coating like the Auto Sun. There is no mirror. It works the same as the Auto Sun (without the coatings) in sunny conditions, but not as well in lower light. It has a slightly redder tint, which makes the view even warmer and more saturated.
Ellume Polarized Horizon Blue
The Horizon Blue is the Copper lens with a blue mirror. This makes the lens even redder and more saturated. This lens still does not have an anti-reflective coating, but it does have hydrophobic/oleophobic in addition to anti-scratch. The VLT is 12%.
Ellume Polarized Dark Grey
The Dark Grey lens from Zeal is the only neutral lens they make. It is dark, coming in at a 9% VLT, and is comfortable in full, bright sun. This has only an anti-scratch coating.
Comparison to Brown Lenses of Different Brands
It is hard to compare the Auto Sun to other lenses, as no other lens I know of transitions from yellow to brown. There are yellow lenses for overcast conditions to compare to, like Smith ChromaPop Low Light Yellow, Costa Silver Sunrise, Island Optics Low Light, etc., but for this section, we will compare brown lenses that are better for sunnier conditions.
Maui Jim HCL Bronze
The Maui Jim HCL Bronze comes in glass, with all coatings, and with a gold bi-gradient mirror. It works amazingly in nearly all sunglasses conditions, from full sun to overcast. It comes in other lens materials in addition to glass, which are also very good, if a step or two behind the glass version.
Serengeti Drivers Polarized
The Serengeti Drivers come in photochromic glass, with all coatings included. The tint is a rose/copper. Together with the HCL Bronze from Maui Jim, this is arguably the most versatile and pleasant lens you can buy.
Costa Del Mar 580 Green Mirror
The Costa Del Mar Green Mirror lens is a heavy brown tint that is suited more to full sun than versatility across all conditions. It feels darker than the Zeal, and redder. It comes in glass with all coatings and an encapsulated mirror for extra scratch resistance.
Island Optics Brown 12
The IO Brown 12 is a fully coated polycarbonate lens with a tint that is similar to the Serengeti Drivers, more rose/copper. For an affordable pair, it offers great value.
Conclusion - Zeal Auto Sun Sunglasses Lens Review -Â Should you buy it?
The Zeal Auto Sun is one of the more unusual lenses on the market, and that uniqueness is both its strength and its limitation.
The versatility of the lens means the Auto Sun can cover a lot of situations with a single lens. It is rarely the absolute best choice for a specific condition, but, with the exception of driving, it is usually close enough to perform well.
Outside of that, the lens is well built for an active lifestyle. The full set of coatings, polarization, and lightweight polycarbonate construction make it practical for everyday use and sports.
If you want a versatile contrast lens to complement a darker grey or green pair, the Auto Sun is a very interesting option. Just think of it as a functional lens designed to adapt across changing conditions rather than a lens optimized for one specific environment.
