Lens Tutorial - Thorlabs

Lens Comparison

Thorlabs offers a wide variety of lenses with very different properties to match the needs of almost any application. However, it is important to choose lenses that are appropriate for a given system. As a general rule, spherical singlets are the most inexpensive, but they suffer from spherical aberration and other monochromatic aberrations. In addition, their single-element design means that they exhibit chromatic aberration that prevents optimum performance with broadband light. For correction of chromatic aberration, achromatic lenses are ideal. These multi-element optics also offer improved aberration correction for monochromatic light. For the best performance with monochromatic laser sources, aspheric optics are recommended. The surfaces of these lenses deviate from spherical sections, allowing for optimal aberration correction. 

You will get efficient and thoughtful service from CLZ.

Table 1.1 gives an overview of the lenses offered by Thorlabs. More details can be found in the Spherical Singlets, Achromatic Lenses, Aspheric Lenses, and Lens Materials tabs on this page.

Table 1.1  Lens Overview Lens Focal Length Conjugate Ratio Chromatic Aberration Correction Applications Spherical Singlet Lenses Plano-Convex Positive 5X - Infinite - Focusing a Collimated Beam;
Collimating a Point Source Bi-Convex Positive 0.2X - 5X - Relay Imaging (Real Object and Image);
Focusing a Divergent Beam Plano-Concave Negative 5X - Infinite - Diverging a Collimated Beam;
Collimating a Convergent Beam Bi-Concave Negative 0.2X - 5X - Relay Imaging (Virtual Object and Image);
Diverging a Convergent Beam Best Form Positive Infinite - Focusing a Collimated Beam;
Collimating a Point Source Achromatic Lenses Cemented Achromatic Doublet Positive Infinite Good Broadband Focusing and Collimation;
Improved Monochromatic Performance Air-Spaced Doublet Positive Infinite Better Broadband Focusing and Collimation;
Optimized On-Axis Performance;
High-Power Applications Cemented Doublet Pair Positive 1X - 3.33X Good Broadband Relay Imaging (Real Object and Image);
Improved Monochromatic Performance Cemented Achromatic Triplet Positive 1X - Infinite Best Broadband Focusing, Collimation, and Relay Imaging;
Correction of All Primary Chromatic Aberrations Aspheric Lenses Aspheric Lenses Positive Infinite - Optimized On-Axis Performance;
Laser Diode Collimation;
Fiber Coupling Aspheric Lens Pairs Positive 1X - 3.66X - Optimized On-Axis Performance;
Relay Imaging (Real Object and Image) Aspheric Condensers Positive Infinite - Light Collection;
Collimation of Incoherent Light

Spherical Singlets

Spherical singlets are a good option for many situations where aberrations are not a great concern, as they are the simplest and most inexpensive type of lens to produce. For simple applications, standard plano-convex, plano-concave, bi-convex, and bi-concave lenses are sufficient. For better performance, best form lenses are optimized to reduce aberrations while still retaining spherical surfaces. The use of multiple lens elements within a compound optical system can lead to further performance improvements. Meniscus lenses are often employed in these multi-element optical systems, although they are rarely used alone. For the most demanding applications, spherical singlets will not perform as well as achromatic lenses (for both broadband and monochromatic sources) or aspheric lenses (for monochromatic sources). More details about these other types of lenses can be found on the Achromatic Lenses and Aspheric Lenses tabs.

Standard Singlets

Thorlabs offers several basic singlet designs: Plano-Convex, Bi-Convex, Plano-Concave, and Bi-Concave. Each of these lenses is suited for different applications. Plano-convex and bi-convex lenses are positive (i.e., they have a positive focal length) and will bring collimated light to a focus, while plano-concave and bi-concave lenses are negative and will cause collimated light to diverge. Each singlet lens shape minimizes aberrations for a certain conjugate ratio, defined as the ratio of the object distance to the image distance (these are called conjugate distances).

Table 2.1  Positive Lenses Plano-Convex Lenses Bi-Convex Lenses Plano-convex lenses are best used where one conjugate distance is more than five times the other conjugate distance. The performance of this lens shape is best for an infinite conjugate ratio (focusing collimated light or collimating a point source). Bi-convex lenses perform best when one conjugate distance is between 0.2 and 5 times the other conjugate distance. The performance of this lens shape is best when the object and image distances are the same. Table 2.2  Negative Lenses Plano-Concave Lenses Bi-Concave Lenses Plano-concave lenses are best used when one conjugate distance is more than five times the other conjugate distance. They introduce negative spherical aberration and can be used to balance the positive spherical aberration introduced by positive focal length singlets. Bi-concave lenses have a negative focal lengths and are commonly used to increase the divergence of converging light.

Minimizing Aberrations

To minimize spherical aberration, a lens should be oriented so that the surface with the greatest curvature is facing the furthest conjugate point. For plano-convex and plano-concave lenses used at infinite conjugate ratios, this means that the curved surface should face the collimated beam (as shown in the drawings in Tables 2.1 and 2.2). The f-number of a lens, defined as the focal length divided by the aperture diameter, has a significant impact on the magnitude of image aberrations. Lenses with a small f-number ("fast" lenses) introduce significantly more aberrations than lenses with a large f-number ("slow" lenses). Lens shape becomes important for f-numbers below about f/10, and alternatives to spherical singlets (such as achromatic lenses and aspheric lenses) should be considered for f-numbers below about f/2.

Best Form Lenses

Figure 2.3  Spherical Aberration and Coma vs. Front Surface Curvature

Best form lenses are designed to minimize spherical aberration and coma (an aberration introduced for light not on the optical axis) while still using spherical surfaces to form the lens. The use of a spherical design makes best form lenses easier to manufacture than aspheric lenses (described on the Aspheric Lenses tab), reducing costs. Each side of a best form lens is polished so that it has a different radius of curvature, providing the best possible performance for a spherical singlet. For small input beam diameters, best form lenses are even capable of diffraction limited performance. These lenses are commonly used in high-power applications where cemented achromatic lenses are not an option (see the Achromatic Lenses tab for more information).

Table 2.4  Best Form Lenses Best form lenses are designed to minimize aberrations while still using spherical surfaces to form the lens. These lenses are optimized for an infinite conjugate ratio and are ideal for focusing collimated light or collimating a point source.

Figure 2.3 shows a plot of coma and spherical aberration as a function of the curvature of the front face of a lens (the curvature is the inverse of the radius of curvature). The minimum spherical aberration nearly coincides with the zero coma point; the curvature where this minimum occurs is the basis for a “best form” design.

Meniscus Lenses and Multi-Element Lens Systems

Meniscus lenses are commonly used in multi-element optical systems to modify the focal length without introducing significant spherical aberration. The optical performance of multi-element lens systems is often significantly better than the performance of single lenses. In these systems, aberrations introduced by one element can be corrected by subsequent optics. These lenses have one convex and one concave surface, and they can be either positive or negative.

Table 2.5  Meniscus Lenses Positive Meniscus Lenses Negative Meniscus Lenses Positive meniscus lenses are typically used in cominbation with another lens in a compound optical assembly. When used in this configuration, a positive meniscus lens will shorten the focal length and increase the numerical aperture (NA) of the system without introducing significant spherical aberration. Negative meniscus lenses are typically used in combination with another lens in a compound optical assembly. When used in this configuration, a negative meniscus lens will increase the focal length and decrease the numerical aperture (NA) of the system.

Figure 2.6 shows the performance gains that can be achieved by using multi-element lens systems. A single element plano-convex lens with a focal length of 100 mm produces a spot size of 240 µm [Figure 2.6 (a)]. In addition, the single lens introduces 2.2 mm of spherical aberration, defined as the distance betwen the marginal focus (where rays on the very edge of the lens focus) and the paraxial focus (where rays in the center of the lens focus). By combining two plano-convex lenses with focal lengths of 100 mm, for an effective focal length of 50 mm, the focused spot size is decreased to 81 µm and the spherical aberration is reduced to 0.8 mm [Figure 2.6 (b)]. An even better option, however, is to combine the f=100 mm plano-convex lens with a positive f=100 mm meniscus lens. Figure 2.6 (c) shows the results: the focused spot size is reduced to 21 µm and the spherical aberration is reduced to 0.3 mm. Note that the convex surfaces of both lenses should be facing away from the image point.

Figure 2.6  Improved Performance of Multi-Element Systems

Achromatic Lenses

Figure 3.1  Focusing White Light with a Plano-Convex and an Achromatic Doublet Lens

Achromatic lenses, or achromats, consist of two or three lens elements and offer significantly better performance than simple singlet lenses. The lenses in an achromatic doublet or triplet are either cemented together or have an air gap between them and typically include both positive and negative elements with different indices of refraction. This multi-element design offers a number of advantages, including reduced chromatic aberration, improved imaging of monochromatic light, and improved off-axis performance. The different kinds of achromatic lenses and their properties, such as conjugate ratio and damage threshold, are described at the bottom of this page. For any application with demanding imaging or laser beam manipulation needs, these achromats should be considered.

Reduced Chromatic Aberration

Since the index of refraction of a material depends upon the incident wavelength, the focal length of a single lens depends on the incident wavelength. This leads to a blurred focal spot when singlet lenses are used with a white light source. This phenomenon is known as chromatic aberration. An achromatic lens can partially compensate for chromatic aberration by virtue of its multi-element design.

The constituent optical elements of an achromatic lens generally include both positive and negative lenses with different amounts of dispersion. If the material dispersion values and focal lengths of these constituent lenses are chosen carefully, a partial cancellation of the chromatic aberration can be achieved. Typically, achromatic lenses are designed to have the same focal length for two wavelengths at opposite ends of the visible spectrum. This results in a nearly constant focal length across a wide range of wavelengths.

The use of achromats is beneficial for any broadband imaging application that utilizes a large wavelength range. Figure 3.1 shows the effect on focal length for a number of different wavelengths incident on both a plano-convex singlet and achromatic doublet. The diameter of the focal spot is reduced from 147 µm to 17 µm by replacing the singlet with the achromatic doublet.

Improved Imaging for Monochromatic Light

When an optical system is used with monochromatic light, the chromatic aberration discussed above is inconsequential. However, spherical singlets can still introduce significant monochromatic aberrations, such as spherical aberration and coma. The multi-element design of achromatic lenses reduces these aberrations and leads to significantly increased image quality and tighter focusing of monochromatic light. For example, Figure 3.2 compares the performance of a plano-convex lens and an achromatic doublet in focusing a monochromatic beam. As can be seen, the diameter of the focal spot produced by the doublet is 4.2 times smaller than that produced by the singlet.

Figure 3.2  Focusing a Monochromatic Beam with Both a Plano-Convex and Achromatic Doublet Lens
Figure 3.3  Off-Axis Performance for a Plano-Convex and an Achromatic Doublet Lens

Superior Off-Axis Performance

For spherical singlets, the effect of off-axis aberrations can significantly compromise the performance of the lens if the beam is not propagating through the exact center of the lens. Achromatic lenses are less sensitive to centration, meaning that off-lens-axis beams are focused to almost the same spot as on-axis beams. Generally, achromatic triplets are even better than doublets at correcting for these off-axis effects.

Figure 3.3 shows two Ø25 mm, f=50.0 mm lenses, one of which is a plano-convex spherical singlet and the other is an achromatic doublet. Each lens has one beam propagating along the optical axis and another propagating parallel to the axis but offset by 8 mm. The achromatic doublet reduces both lateral and transverse aberrations; the lateral displacement of the focal points (circled in the diagram) is reduced by a factor of six and the focal spot diameter is also significantly smaller.

Selecting an Achromatic Lens

Achromatic lenses are a good choice for any demanding optical application, as they offer substantially better performance than spherical singlets. Cemented achromatic doublets are sufficient for most applications at infinite conjugates, and cemented doublet pairs are ideal for finite conjugates. However, the cement used in these optics reduces their damage threshold and limits their usability in high-power systems. Air-spaced doublets are ideal for high-power applications, as they have a greater damage threshold than cemented achromats. In addition, air-spaced doublets have two more design variables than cemented doublets because the interior lens surfaces do not need to have the same curvature. These extra variables allow the performance of air-spaced doublets to far exceed the performance of cemented doublets in terms of transmitted wavefront error, spot size, and aberrations. However, air-spaced doublets are also more expensive than cemented doublets.

Achromatic triplets can be designed for both finite (Steinheil Triplet) and infinite (Hastings Triplet) conjugate ratios. These triplets consist of a low-index center element cemented between two identical high-index outer elements. They are capable of correcting both axial and laterial chromatic aberration, and their symmetric design provides enhanced performance relative to cemented doublets.

Table 3.4  Achromatic Lenses Cemented Doublets Air-Spaced Doublets Achromatic doublets offer several advantages over simple singlet lenses. These include a minimization of chromatic aberration, improved off-axis performance, and smaller focal spots. These doublets have positive focal lengths and are optimized for an infinite conjugate ratio. Air-spaced doublets offer even better performance than cemented doublets, as they are optimized with respect to the lens separation. These optics are ideal for high power applications, as they offer a greater damage threshold than cemented doublets. These doublets have positive focal lengths and are optimized for an infinite conjugate ratio. Doublet Pairs Achromatic Triplets Achromatic doublet pairs offer the advantages of achromatic lenses, while being optimized for finite conjugates. These pairs are ideal for image relay and magnification systems. Achromatic triplets offer even better performance than achromatic doublets. An achromatic triplet is the simplest lens that corrects all primary chromatic aberrations. Steinheil Triplets are optimized for finite conjugate ratios, while Hastings Triplets are optimized for infinite conjugate ratios.

Aspheric Lenses

Aspheric lenses offer optimized on-axis performance at an infinite conjugate ratio, an advantage over spherical singlets and achromatic doublets. While individual spherical lenses can refract light at only small angles before spherical aberration is introduced, aspheric lenses are designed with curved surfaces that deviate from a sphere. This deviation is designed to eliminate spherical aberrations when light is refracted at large angles. As such, aspheric lenses are ideal for applications like laser diode collimation and fiber coupling that require a small f-number and large numerical aperture (NA). However, aspheric lenses are made from a single material and suffer from chromatic aberration. As such, they are typically used for monochromatic applications.

Figure 4.1  Theoretical Diffraction-Limited Spot Size

Theoretical Diffraction-Limited Performance

Figure 4.1 shows ray tracing results for a 780 nm beam at the image plane of an ASL lens (f = 79.0 mm at 780 nm). The Airy disk has a diameter of 6.538 µm, and is depicted by a black circle. Since all the rays (in blue) are well within the diameter, the theoretical spot size is diffraction limited.

Aspheric lenses have several particularly important applications, including laser diode collimation, fiber coupling, and light collection.

Figure 4.2  Collimating a Laser Diode Output with an Aspheric Lens

Collimating Laser Diodes

In laser diode systems, difficulties with aberration correction are compounded by the beam’s high divergence angle. Because of spherical aberration, three or four spherical singlet elements are often required to collimate the light from a laser diode. A single aspheric lens can collimate the highly divergent emission of a laser diode without introducing spherical aberration, as shown in Figure 4.2. Again, the flatter side of the optic should face the source for optimum performance.

When choosing an aspheric lens for collimation of a laser diode, the first step is to determine the numerical aperture of the diode. This value is given by the sine of the largest FWHM divergence angle of the laser light. Then, an aspheric lens should be chosen that has roughly twice the numerical aperture of the laser. This will ensure that the aspheric lens collects as much light as possible (much of which is outside the FWHM divergence angle).

Fiber Coupling

When coupling light into a fiber, it is often necessary to focus a collimated beam of light to a diffraction-limited spot. Typically, single spherical elements and achromatic doublets are not capable of achieving such a small spot size; spherical aberration is the limiting factor rather than diffraction. Since aspheric lenses are designed to eliminate spherical aberration, only diffraction limits the size of the focal spot.

When choosing an aspheric lens for coupling light into a single mode fiber, the diffraction-limited spot size should be matched to the mode field diameter (MFD) of the fiber. The required focal length for the lens can easily be calculated from the MFD and the beam diameter. If an aspheric lens is not available that provides an exact match, then choose the aspheric lens with a focal length that is shorter than the calculation yields. Alternatively, if the clear aperture of the aspheric lens is large enough, the beam can be expanded before the aspheric lens, which has the result of reducing the spot size of the focused beam.

Light Collection

Many applications, such as microscopy, make use incoherent lamps and high-power LEDs as illumination sources. These applications benefit from the efficient collection of as much light as possible, suggesting the use of a large aperture lens to collimate the output of the source. Unfortunately, large aperture lenses tend to introduce more aberration than smaller lenses, reducing the quality of the resulting collimated light. Aspheric condenser lenses are ideal for efficient light collection, as they offer large diameters and numerical apertures as well as the reduced spherical aberration of an aspheric design.

If you want to learn more, please visit our website Optical Spherical Lenses For Imaging.

Table 4.3  Aspheric Lenses Aspheric Lenses Aspheric Collimators Aspheric lenses focus or collimate light without introducing spherical aberration into the transmitted wavefront. Molded aspheric lenses are economical and available in both glass and plastic. For better performance, precision polished aspheric lenses introduce substantially less wavefront error and are offered with larger diameters. Aspheric collimators are designed to collimate divergent light with diffraction-limited performance. We offer fixed focus and adjustable focus fiber collimators as well as laser diode collimation tubes. Aspheric Lens Pairs Aspheric Condensers Aspheric lens pairs are designed for near aberration-free finite conjugate imaging. These pairs are ideal for image relay and magnification systems. Aspheric condensers are designed for high-efficiency illumination applications. They offer reduced spherical aberration with large apertures and low f-numbers. They are ideal for collimating light from a lamp or LED.

Lens Materials

Thorlabs' wide breadth of optics manufacturing capabilities allows us to offer lenses made from a variety of optical materials. Table 5.1 should aid with the selection of a lens best suited for use at a particular wavelength. To view transmission plots for the uncoated materials, please click on the appropriate icon below. For more details on optical substrates, please see our Optical Substrates tutorial.

Table 5.1  Lens Materials Material Transmission Description Transmission Plots N-BK7 350 nm - 2.0 µm N-BK7 is a RoHS-compliant borosilicate crown glass. It is probably the most common optical glass used for high quality optical components. UV Fused Silica (UVFS) 185 nm - 2.1 µm UV-grade fused silica offers high transmission in the deep UV and extremely low fluorescence levels compared to natural quartz, making it an ideal choice for applications from the UV to the near IR. In addition, UV fused silica has better homogeneity and a lower coefficient of thermal expansion than N-BK7. N-SF11 420 nm - 2.3 µm N-SF11 is a RoHS-compliant dense-flint glass with a high index of refraction and a low Abbe number. This glass exhibits higher dispersion than N-BK7 but many of its other properties are comparable. Calcium Fluoride (CaF2) 180 nm - 8.0 µm Calcium fluoride has a low refractive index and is mechanically and environmentally stable. It is ideal for any demanding applications where its high damage threshold, low fluorescence, and high homogeneity are beneficial. Barium Fluoride (BaF2) 200 nm - 11.0 µm Barium fluoride's properties are similar to those of calcium fluoride, but it is more resistant to high-energy radiation. It is, however, less resistant to water damage. Silicon
(Si) 1.2 - 8.0 µm Silicon offers high thermal conductivity and low density. However, since it has a strong absorption band at 9 microns, it is not suitable for use in CO2 laser transmission applications. Zinc Selenide (ZnSe) 600 nm - 16.0 µm Due to its wide transmission band and low absorption in the red portion of the visible spectrum, Zinc Selenide is commonly used in optical systems that combine CO2 lasers, operating at 10.6 µm, with inexpensive HeNe alignment lasers. Germanium (Ge) 2.0 - 16 µm Germanium is well suited for IR laser applications. The element is inert to air, water, alkalis, and acids (except nitric acid), but its transmission properties are highly temperature sensitive. Magnesium Fluoride (MgF2) 200 nm - 6.0 µm Magnesium Fluoride is an extremely rugged and durable material, making it useful in high-stress environments. It is commonly used in machine vision, microscopy, and industrial applications. PTFE 30 µm - 1.0 mm PTFE has a low dielectric constant of approximately 1.96 @ 520 GHz and an index of refraction of 1.4. The material is especially useful for application in the terahertz range, which is defined as the frequency range from 300 GHz to 10 THz, or the wavelength range of 30 μm to 1 mm.

That is my general understanding. Think of it this way, a Spherical lens projects an image circle where and an anamorphic projects an oval (I think in any cast a squeezed image.)

Pick up Cinemtography: 3rd Edition it has a great little graphic showing how each works:

http://www.amazon.com/Cinematography-Third...&sr=8-1

and is quite a pleasant read.

Hey,

a spherical lense is considered a simpler lense in optics as it consist of a part of a full sphere or a sylinder.

The problem with spherical lenses incorporated into optics in general are that they produce optical aberrations,

witch can for example result in loss of contrast and resolution, often towards the outer parts of an image.

Aspherical lenses are dificult to produce as they need a more hands-on aproach in production (a least when they are made of glass..)

The lens will bend certain parts of the image, and reducing the optical aberrations that we all hate in cheap zooms, older zeiss primes etc.

Another great thing is that an aspherical lens may incorporate the optical qualities of many spherical lense elements, making the acctual lense

mounted on the camera, lighter and with less breating when focusing.

The new master prime series from Zeiss has been put together with aspherical lense elements and produces super sharp images (to sharp maybe..?)

the only problem is that they are much more expensive to produce, bye and in our case - rent.

Martin, while all of that is true, for optics, at least in my own experience, in terms of cinematography, spherical lenses v anamorphic lenses are just the processes, even if the lens itself is aspherical. Just that when you shoot say 3-perf for a 2:40 extraction the cinematographic process is referred to as "spherical." At least that's what I got the question was asking-- more nomenclature as opposed to actual science behind it.

Thank you all for your answers to my query. Adrian, I'm going to pick up Cinematography-3rd edition. I'm still not sure which lenses are spherical. For instance, I'm holding in my hand an Angenieux 10-150 for my 16mm camera. Would this lens be considered spherical? Can any of you give me some more examples of spherical and non-spherical lenses? Please - not too technical, remember, this is the idiot section of the forum. Thanks.

Thank you all for your answers to my query. Adrian, I'm going to pick up Cinematography-3rd edition. I'm still not sure which lenses are spherical. For instance, I'm holding in my hand an Angenieux 10-150 for my 16mm camera. Would this lens be considered spherical? Can any of you give me some more examples of spherical and non-spherical lenses? Please - not too technical, remember, this is the idiot section of the forum. Thanks.

Think of a big cone of light entering the lens it flips upside down at the nodal point and is projected out the back of the lens. The reason that the image is a rectangle and not a circle is because you have an aperture plate that blocks or crops out the rest of the image. If you were to do the same the thing to an anamorphic lens which is not spherical (round) your image would be squeezed in the middle. It goes onto the film squeezed and is projected by a projector with a lens that un-squeezes the image so it now appears normal yet wider. Don't over think this. Take the 10-150 and look through the end of it. The image should be round, spherical. Most lenses are spherical.

Tom,

I agrea, the Angenieux is most probably spherical, the new Optimos are aspherical as far as i know,

but the 10-150 is from an age where production of aspherical elements was difficult.

I found an interesting thing on the nodal point(s) not being what you describe TOM,

check it out: http://doug.kerr.home.att.net/pumpkin/Pivot_Point.pdf

The only reason we think the nodal point is where the image is flipped upside down (and where we are mislead to tilt/pan the cam on f.ex the F7)

is because "the entrance pupil" where i supposedly acctually happens,

sometimes/often coencides with on of two nodal points.

These are not my thoughts, I just found them interesting, having believed for years I was using the right term...

OK,

now I feel like a nerd.

All my lens books are in the garage burried. Disregard nodal point. I can't remember exactly what it is called. I'm lucky if I remember what I had for breakfast, if I ate at all. The one important thing that you students need to remember is you don't have to know everything. You have to know a lot that's for sure. Don't look at the camera, look through the camera. You are making art, not science. Science is just another tool. Think more about the quality of light around you. Look how it hits people's faces. Your light meter will tell you quantity. Sometime people get so wrapped up in the technical side they miss the art.

:blink: I've seen the term "spherical lens" in a few 2 perf Techniscope threads. Does this mean any lens that is not anamorphic? Are most or all primes and zooms spherical lenses? Are there non-spherical lenses?

I think there are two issues being discussed here.

In Cinematogroahy lingo, If you are NOT shooting anamorphic (in-lens optical squeezing), then you are said to be shooting spherical, no matter if it's 2 Perf, 3 perf or 4 perf.

As a separate note, some lens designs (be they anamorphic or not) have aspherical elements WITHIN the lens itself which correct for OTHER optical issues or make it possible to have smaller and lighter lenses.

If you look at an aspherical element from the side, it's not a concave or convex shape, but changes across it's surface. it may still produce what tom calls a spherical image when you look from the rear.

This hasn't got anything to do with the fact that it's anamorphic or not, which is a choice not a correction. The anamorphic element in an anamorphic lens is separate to any aspherical elements it may have.

jb

Contact us to discuss your requirements of Coating Witness Samples Wholesaler. Our experienced sales team can help you identify the options that best suit your needs.