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Ever wonder what the difference is between an aspherical lens and a &#;normal&#; spherical lens?

Maybe you&#;re looking at buying a new lens and aren&#;t sure if you should fork out the extra cash for the one marked &#;Asph Lens,&#; or you&#;re just wondering what makes aspheric lenses expensive.

Either way, knowing what an aspherical lens is and what it does will help you in better understanding your gear and when it comes time to purchase new types of camera lenses, you&#;ll have a better idea of what to buy.

So let&#;s take a look at the aspherical lens, what it does, and why it just might be worth that extra hit to your wallet.

What is an Aspherical Camera Lens?

An aspherical lens is simply a lens that doesn&#;t have a spherical surface shape. Instead, it has an aspheric surface (i.e. non-spherical), usually with counter-curves near its edges.

These counter-curves direct light rays hitting the edges of a lens to converge at the same point of focus as the light rays hitting the center.

Standard lenses use spherical elements, many of which aren&#;t natively able to direct the light reaching its edges to the same focal point as the light reaching its center.

Designers &#; especially with wide-angle lenses &#; often have to stop-down their optical systems to exclude the corners so as to avoid an excess of field curvature.

The lens surface of an aspherical lens corrects for this, making it possible to shoot at wider apertures and allowing us to use the entire surface of the lens.

What is an Aspherical Camera Lens Used for?

Aspherical lenses are used primarily in high-end optics to create sharper images and reduce or eliminate certain optical imperfections (i.e. chromatic aberrations, field curvature, etc.).

They also allow manufacturers to create smaller and lighter lenses since they reduce the need for numerous lens elements and lens groups.

As you can imagine, aspherical lenses aren&#;t just used in cameras. They&#;re a vital part of any system that needs a high standard of optical quality, from telescopes and contact lenses, to rifle sights and missile-guidance systems.

Aspheric eyeglass lenses are especially useful in combatting astigmatism.

Spherical and Aspherical Lenses: What are the Differences?

1. Physically, spherical lenses have a front surface that is spherical, meaning the curve is the same from top to bottom and left to right &#; like a portion of a sphere.

Aspheric lenses, on the other hand, have curves that deviate from the regular spherical curve.

2. Aspherical lenses are much more challenging to manufacture. The result is a much deeper hit to your wallet!

The aspherical glass lenses used in top-of-the-line telephoto and wide-angle lenses are particularly expensive. They&#;re usually ground and polished by hand.

Less expensive aspheric lenses &#; like those used in point-and-shoots &#; will often be made of plastic or resin.

3. An aspherical lens element has much more precise control of how light travels inside your lens. So much so, that one asphere can oftentimes negate the need for many of the standard lens elements that would otherwise be needed to achieve the same effect.

The result?  A much lighter, more compact lens.

Goto RuiQi to know more.

What is Spherical Aberration?

Ideally, light rays, when passing through a camera lens element, would all converge at a single point thereby creating a sharp focus. Unfortunately, this isn&#;t the case with many spherical lenses.

Spherical aberrations occur when incoming light rays pass through a spherical lens and focus at different points, causing blurry images and reducing overall image quality.

One way to compensate for this is by using a combination of concave and convex lens elements. Another way is by using an aspheric lens.

Aspherical lenses are curved outwards on their rear element so that they can better direct light rays into a single focal point. These counter-curves help correct spherical aberration, creating sharper images.

Advantages & Disadvantages of Aspheric Camera Lenses

Are aspherical camera lenses better than normal camera lenses?

Absolutely! They&#;ll make your lens lighter, your images sharper, and bring aberrations and distortion down to near zero. The only downside is how much they cost.

In the past, only pros could afford such top-of-the-line optics. These days they&#;re still spendy, but at least they&#;re not completely the ballpark for ordinary photographers.

Final Words

It&#;s really amazing how far modern optics have come. Not too long ago, only pros could afford full-frame cameras and aspherical lenses. Now those of us in the prosumer world can get them too.

Of course, asph lenses are considerably more expensive than spherical lenses, but high-quality glass will last a lifetime, so if you can spring for the high-performing lens, go for it!

What do you think? Where do you stand in the aspheric lens vs normal camera lens debate?

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What are aspheric lenses?

Aspheric lenses are slimmer, flatter optical lenses compared to traditional prescription lenses. These lenses are available in both glasses and contacts, making more stylish options available to prescription lens wearers than ever.

If the word aspheric is new to you, we&#;ll break down everything you need to know about what aspheric lenses are, how they work, and the benefits and drawbacks of wearing them. By the end of this article, you&#;ll feel primed and ready to discuss aspheric lenses with your doctor if they are of interest to you.

How aspheric lenses work

The technology behind aspheric glasses and contact lenses is directly related to advances made in camera lens technology. Just like the human eye, some camera lenses are shaped in such a way that visual aberrations and distortion can occur in the images they capture. The shape of the eye can also contribute to distorted vision. That&#;s why lenses are specially designed to balance and correct for the unique shape of a person&#;s eye&#;and why the technology has had to come a rather long way.

While traditional lenses have gone far to help the millions of people who suffer from farsightedness or nearsightedness, they add a marked spherical, convex curvature to the shape of the lens. This can distort the appearance of the eyes and facial areas. Traditional convex lenses can create a magnifying, bug-eyed effect on farsighted prescriptions or a minimizing, beady-eyed effect on nearsighted prescriptions. This noticeable curvature of the lens distorts the appearance of the wearer and the glasses alike, detracting from overall perceived attractiveness while also dealing an unnecessary blow to self-confidence.

Benefits of aspheric lenses

With the advancement of aspheric lens technology, we now have more glasses frame styles available to more people than ever, with significantly less bulging of the lens and a lightweight feel for comfortable wear. These advanced lenses are cut to a slimmer profile, with much flatter curves that are strategically shaped depending upon the wearer&#;s prescription. This slim profile means that the glasses frames can sit closer to the face for a much more natural, streamlined look. This is a big advancement for folks with especially high prescriptions. If you&#;re in the market for aspheric lenses, limited frame materials, shapes, and sizes are no longer an issue, either.

Not only are &#;coke bottle lenses&#; a thing of the past, but aspheric lenses also offer a better degree of vision correction. When wearing traditional lenses, you may notice some visual distortion when you look anywhere other than the direct center of the lens. Aspheric lenses, on the other hand, promote a wider field of vision with better peripheral vision and more consistent overall image magnification, allowing for clearer and more accurate vision. This is the same reason many photographers prefer aspheric camera lenses - a wider field of vision means more of the beautiful world is accurately captured in a single glance.

Drawbacks of aspheric lenses

The major disadvantage of aspheric lenses is their price. These advanced vision correcting lenses cost more to manufacture than traditional lenses do, involving more steps, more precision, and more labor. If you have an extremely mild need for vision correction, then aspheric lenses may not be the most logical choice for you.

Another factor to consider is that, due to their flatter profile and closer proximity to the face, aspheric lenses may produce noticeable reflections for some wearers. Anti-reflective coating is recommended for all aspheric lens wearers to eliminate any potential for visual distraction that reflections can cause.

Finally, as mentioned in the beginning of this article, aspheric lenses are also an option for some contact lens wearers. However, the performance of aspheric contact lenses, when compared with that of aspheric glasses, may leave something to be desired. Many find that regular, spherical contact lenses work just as well, if not better than the newer aspherical contact lenses do. With two primary options of aspheric contact lens prescriptions being bifocal and multifocal, visual aberrations can be corrected in the wearer. However, visual contrast may reduce slightly, while glare caused by driving at night may increase - particularly for those who wear multifocal aspheric contacts. For these reasons, aspheric contact lenses may not be for everyone.

Who should wear aspheric lenses

In general, many people with moderate to high need of vision correction for nearsightedness or farsightedness can benefit from the advances of aspheric lenses, particularly if worn in prescription glasses. Those with lower prescriptions will not see noticeable improvements to make the cost of aspheric lenses worthwhile. While some may want to try aspheric contact lenses, particularly those with bifocal rather than multifocal prescriptions, the benefits are mixed and should be discussed with your eye doctor. Those with astigmatism may not benefit as high as others and may be better off discussing toric lens options. Finally, aspheric lenses are a good option for many who use non-prescription reading glasses, too! If your readers are at a high reading power of +4.00 or higher, you may want to explore aspheric options.

Conclusion

As you can see, aspheric lenses offer many aesthetic and vision-correcting benefits for their wearers. But just like any prescription, these types of glasses or contact lenses should be thoroughly discussed with your eye doctor to make the best decision for you. Even if you&#;re considering non-prescription readers with aspheric lenses, it's worth it to mention the change to your doctor.

Your eye shape is unique to you and you alone; this means that your lenses, whether aspheric prescription or non-prescription, must be customized to your unique eye shape. An experienced optometrist can assess your vision needs and recommend the most appropriate and flattering lenses for you. Get in touch with our team today to discuss your interest in aspheric lenses!

Are you interested in learning more about Aspheric Cylindrical Lens? Contact us today to secure an expert consultation!