Sunex has many online tools designed to help you find a lens according to your specifications that is best suited to your application. Once a lens is identified based on first order parameters, there can be many options or variants of that part number (PN). It is therefore useful to know how to interpret Sunex part numbers and the PN itself can provide insight into the lens’ performance or intended use. The intention of this…
New imagers can capture light intensity variations up to six or more orders of magnitude within the same image frame (+120db HDR, 20*LOG(1e6)), and together with the growing number of applications using computer vision, they are putting very demanding requirements on lens performance. Designing and manufacturing an HDR lens is probably as much art as it is science and engineering. Sunex HDR Optimized™ lenses are the first stepping stone to build a system, that performs…
Many applications require that CMOS or CCD imaging lenses be optimized for a finite object, that is, for an object distance closer than “infinity.” The practical definition of infinity varies based on individual use-case requirements and specific lens being used. It can be defined in different ways, such as spot size, through-focus MTF, etc. As a general rule of thumb, and depending on F/#, infinity is generally 100-200x the focal length (EFL) of the lens…
The general guideline for cleaning optics is “if it’s not dirty, don’t clean it”. Handling optics increases their chances of getting dirty or damaged, so you should clean optics only when necessary. Both the proper cleaning products and proper methods are equally important to cleaning the optic. There are different methods for cleaning and certain specialized optics require particular attention and change in procedures. Below are general guidelines to be used as a reference only…
One of the questions we frequently get at Sunex is some variation of, “Can I modify a standard lens, and what does this entail?” The answer to this question is, “Yes!” depending on what you would like to modify, of course! In general, there are four categories of what can potentially be modified on a standard lens: External Mechanical Features Coatings/Filters F/# Specifications While first-order lens parameters which are inherent to the optical design typically…
A typical lens assembly consists of several lens elements inside a cylindrical barrel. Due to the mechanical clearance requirement, the internal element diameters must be smaller than the barrel internal diameter. This creates potential risks that could result in boresight errors or changes: Lens to lens variance of the optical axis due to manufacturing tolerance A possible lateral shift of individual elements overtime due to strenuous conditions The first potential risk (lens to lens variance)…
Lens distortion is a commonly used term in the general specification of lenses. The classic, textbook definition of distortion includes barrel and pincushion type distortions. These concepts are useful for photographic optics where the field of view of the lenses are not extreme. Lenses designed for machine or computer vision applications can have extreme field of views. Field of view greater than 100 degrees are common specifications for machine vision lenses. We need to develop…
One modification that is commonly requested by our Customers is changing the F/# of a standard lens. The most common reason to stop down a lens is to resolve more detail and gain greater depth of field in an image. However, the term itself can sometimes be confusing, and there are limits to how much you can stop down a lens before encountering diminishing returns. “Stopping down a lens” refers to increasing the numerical f-stop…
Super wide-angle lenses and fisheye lenses have pronounced barrel distortion. When viewing a flat object, off-axis features are “squeezed” significantly relative to the on-axis ones. This reduces the effective off-axis resolutions. For many applications, it is an undesirable effect. It is possible to post-processing the image to reduce this effect. However, post-processing in software reduces the image quality because the missing off-axis information must now be interpolated. We created a new class of super wide-angle…
Certain applications require a broad spectral operating range and customers oftentimes inquire whether a lens can perform “well” out to their wavelength of interest. These requests typically involve both visible (VIS) and near infrared (NIR) wavelengths. For purposes of this discussion, a wavelength range roughly from 470nm (or lower) out to about 850-950nm is assumed. Fundamentally, it is important to consider the use-case of the lens and determine how the VIS and NIR wavelengths apply…
The imaging applications in the automotive industry go through rapid changes. Where just a couple of years ago a lens/camera just needed to survive, the expectations moved to better performance, consistent and reliable over a wide temperature range. Below is a video of the talk Sunex presented at the AutoSens 2017 show, sharing experiences and observations on how requirement changes on the camera level impact consideration and design approaches on the lens level. Some of…
“Scaling’ refers to a method where a known lens design is proportionally enlarged or reduced geometrically to meet a different image size requirement from what the lens was originally designed for. For example, say, we have a lens that was originally designed for a 1/3” format sensor with an image circle of 6mm, we can “scale” up that design to make the image circle 8mm. This new scaled-up design is now capable of supporting a…
With the advent of computers and more processing power, the art of lens design has matured. But computers cannot solve the whole problem. A computer can select a configuration and designer optimizes that configuration. Can a machine learning algorithm find the absolute best lens design? Yes, if you try an infinite number of different design form. But..”I still want to be young when we get there!” Hence, the journey of developing an elegant design will…
One of the most common questions Sunex receives is regarding the need for Active Alignment of lens modules. Initially, customers designing or prototyping an imaging system may find it hard to see the value of actively aligned modules. After all, active alignment requires a significant tooling investment. In addition, during the prototyping phase, customers can typically achieve great results in small numbers by manually focusing the lens and gluing it into an off-the-shelf camera module….
Many customers use Sunex lenses in a custom housing unit which is unique to their particular application. In many wide-angle lenses, especially fisheye lenses, it is important to understand where the rays of the maximum field of view for a specific sensor are located with respect to a reference datum on the lens in order to design a housing or hood that will maximize the field and not clip the rays. Understanding the concept of…
At Sunex, we get the above question frequently, but the answer is not straight-forward. Specifying an operating temperature range for a lens can be tricky, because generally speaking, there is no point within a lens’ physically survivable temp range that it will suddenly “fail.” Since the index of refraction is a function of temperature, nearly all lenses experience some performance degradation over temperature, yet could still reasonably be considered “operational” well beyond their specified nominal…
Sunex Inc. has developed design expertise, process know-how, and manufacturing facilities to eliminate or minimize optical noise (such as ghosts, flare, starbursts, spurious images) in lenses for high-performance applications. Lenses designed and manufactured with this process are known as NoGhost™ lenses. The following comparison demonstrates the advantages of a NoGhost™ lens: At Sunex, we are always interested to learn about new applications and project requirements. If we can’t find something which works in our current…
Following up on the article Optical Tolerances – Part 1, Part 2 discusses the quantitative measure of image quality. The modulation transfer function (MTF) is a quantitative measure of image quality. MTF describes the ability of a lens or system to transfer object contrast to the image. Consider a sine-wave chart in the form of a positive transparency in which transmittance varies in one dimension. Assume that the transparency is viewed against a uniformly illuminated…
Tolerance is a critical factor impacting the performance and cost of an optical system. Optical components usually require much tighter tolerances than that commonly associated with mechanical components. As a result, special equipment and techniques are used in the manufacturing process and measuring of the optical tolerances. SURFACE ACCURACY When attempting to specify how closely an optical surface conforms to its intended shape, a measure of surface accuracy is needed. Surface accuracy can be determined by…
At Sunex we are using our deep design expertise, understanding of material properties, and state-of-the-art high-volume manufacturing process to deliver Digital Imaging Systems based on plastic, glass, and glass/plastic hybrid elements depending on the application, performance and environmental requirements of our clients from the Automotive, Security, VR/AR, Robotics, and Medical industry around the globe. For the 1998 SPIE-Conference, Sunex Founder and CEO Alex Ning wrote a whitepaper discussing the key factors to consider when choosing…
