If one of the surfaces is flat, the lens is planoconvex or planoconcave depending on the curvature of the other surface. Home books introduction to lens design thin lenses. The ultimate guide to lens design using the classic. Nontelecentric lenses are required to produce a flat field of focus but allow that the beam can strike the surface at an angle. Adding a planoconvex converging lens before curved petzval image surface, according to flatfield condition, regardless of lens thickness, we can write r f the radius of curvature of the planoconvex lens is 18 r f n. Focal reducers for refractors with focal ratio of f7 to f9, roughly, have a design reduction factor of about 0. This book holds a unique place in the optics literature.
The ultra flat field 10mm and 15mm telescope eyepieces fit all 1. This book is superb because it lays out different lens design forms suitable for different fnumber and fov. A large part of this book is devoted to a study of possible design procedures for various types of lens or mirror systems, with fully worked examples of each. This increases the field area and reduces the cost of the lens. Optical designers deal with field curvature by adding corrective lens elements to the objective in specially designed flat field objectives. This type of macro is optimized for copying work, such as copying books, paintings, etc. The percival philosophy is similar to that used in modern spectacle lens design. A flat field is obtained, if the following condition is fulfilled. A flat lens is a lens whose flat shape allows it to provide distortionfree imaging, potentially with arbitrarilylarge apertures. By placing the field flattener in the plane of the image, the lens can be shaped as stated in eqs. Some of the smaller work will be rezed up 300 to 400%9x9to 36x36 and printed on my epson 9600. Second, the methods here developed also allow to design a flat lens with a needlelike focus beam with a small spot size, close to the abbes diffraction limit, and an extended depth of focus. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses elements, usually arranged along a common axis.
But at macro distances the dof is very shallow, so the difference becomes visible. Other telescopes incorporate an additional field flattener lens near the focal plane to create a flat field. The petzval lens is one design which has significant amount of field curvature. Flatfield correction is a technique used to improve quality in digital imaging. Prior to the advent of flatfield objectives by the carl zeiss corporation in the late 1930s, the effective flat area of the field at the intermediate image plane was only 10 to 12 millimeters. While advancements in the field over the past two centuries have done much to transform it from the former category to the latter, much of the lens design process remains encapsulated in the experience and knowledge of industry veterans. Placing this lens the distance f from a flat image sensor, image points near the. Flat field correction is a technique used to improve quality in digital imaging. For best optical performance you need to stop down the stacked lens, not the lens attached to the camera. Lens design fundamentals, second edition, is the most comprehensive treatise to be published on the subject of lens design. Flatlens design using field transformation and its.
The ultra flat telescope eyepieces are fully multicoated to maximize light transmission to your eyes, as well as blackened at the lens edges to minimize light scatter. A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. The process of designing lenses is both an art and a science. In spite of that, a lot of lens design books and textbooks that i have read rely. Design for near and distant viewing distances is essentially identical. Optical designers deal with field curvature by adding corrective lens elements to the objective in specially designed flatfield objectives. With a massively improved cycle time, the jobsite walk took less time, and the punch list was entered in real time rather than after the walk. With practical zemax examples joseph geary, are all great books, just to name a few. The lens, made by university of utah electrical engineer rajesh menon and his colleagues, is called a multilevel diffractive lens because it is basically a concentric. A lens with one convex and one concave side is convexconcave or meniscus. This edition has been thoroughly updated and contains integral coverage of soft lenses. For normal lenses, subjects and working distances the curved field may not matter much, since we have enough dof to cover the difference.
Whether youre a team of 5 or 500, fieldlens works for. The reader is urged to follow the logic of these examples and be sure that he understands what is happening, noticing particularly how each available degree of freedom is used to control one aberration. Phasecorrection coated high index prism creates sharp, clear, hd images while the 42mm fully multicoated lenses with flat field technology deliver the brightness and color fidelity you need. Feb 14, 2012 im looking for a flat field lens for photographing my painting and drawings. Germanys carl zeiss jena is derived from, and suggests, a planeflat field curvature. Most of the worlds fastest lenses today are derivatives of the planar. The lens design consists of 10 layers of graded index dielectric in the radial direction and 5 layers in the longitudinal direction. Lens design is, therefore, a strong component of a wellrounded education in optics, and a skill valued by industries employing optical engineers. Jan 24, 2017 however the flat field obviously had some sort of issue. The book begins with an outline of the general process before delving into aberrations, basic lens design forms, and optimization. Design strategy for flatfield schmidt optical system. Now you can address issues before they become problems. This spie field guide provides a working reference for practicing physicists, engineers, and scientists for deciphering the nuances of basic lens design. Dec 26, 2004 among flat field zooms, you can consider a vivitar series 1 90180mm f4.
This legendary zeiss design trademarked planar also known as biotar or biometar in e. Every step from setup specifications to finalizing the design for production is discussed in a straight forward, tangible way. The antireflective coatings reduce ghosting and glow, and aid in providing a darker background. Delving deep into the mechanics of lens design, optics legend warren j. Jan 01, 2006 this title is directed primarily towards health care professionals outside of the united states. The simulation results have been identified that using our method to design fresnel lens the concentration ratio can achieve 2500x while fnumber. A novel technique to design flat fresnel lens with uniform. By placing the field flattener in the plane of the image, the lens can. The introduction of the computer revolutionized the way lenses optical systems are designed and evaluated. A lens with two concave surfaces is biconcave or just concave. I put the lens hood directly against an led tracer panel, leave the focus exactly the same it is taped solid as not to disturb it in moving.
We built fieldlens to solve problems we know first hand. Modern lens design, 2nd edition book oreilly media. For good designs, the distortions can be far below 1%. Telescope optics, a comprehensive manual for amateur. Next, we will design a flatfield schmidt optical system. Prior to the advent of flat field objectives by the carl zeiss corporation in the late 1930s, the effective flat area of the field at the intermediate image plane was only 10 to 12 millimeters.
Many new lens design problems and examples ranging from simple lenses to complex zoom lenses and mirror systems give insight for both the newcomer and specialist in the field rudolf kingslake is regarded as the american father of lens design. Lens design fundamentals rudolf kingslake, applied optics and optical design part 1 and part 2 a. Lenses are made from materials such as glass or plastic, and are ground and polished or molded to a desired shape. Field guide to lens design spie press field guide fg27. They sport folddown rubber eyeguards so you wont scratch your eyeglasses, and also to provide a comfortable feel when viewing through the eyepiece. Unlike the first edition, which was more a collection of lens designs for use in larger projects, the 2nd edition of modern lens design is an optical howto. Dec 30, 2014 this legendary zeiss design trademarked planar also known as biotar or biometar in e. Smith reveals timetested methods for designing topquality lenses.
Also, this method can be used to design concentrated photovoltaic cpv system without secondary optics lens soe. Our team has worked on construction projects large and small. Flat field nir nearir megapixel lenses 3megapixel full hd resolution for 247 surveillance nir radiation refracts differently from visible light, causing blurring in an image captured in the nir spectrum. Computeraided design chapter 9 the maksutov camera 9. Optical design includes 5 or 6 elements to nearly eliminate field curvature distortion eliminates out of focus stars near the edge of the field of view feature large eye lenses and generous eye relief from 9. Practical computeraided lens design by gregory hallock smith. Film cameras, may be able to bend their image planes to compensate, particularly when the lens is fixed and known. Design examples of several widely used modern lenses are provided. By the way, john shaws book which is otherwise excellent gives very poor advice about stacking lenses. Field flattening 201711 herbert gross winter term 2017.
No 35mm slr lens is really comfortable with its pupil forced to the outside. It adds impressive building blocks to the foundation established by a. A novel technique to design flat fresnel lens for cpv system was presented to increase the concentration ratio, reduce optical loss, and improve uniformity of irradiance distribution over receiver. At 180mm, it does not give a flat field performance or a 70180mm f4.
In some cases, the mentioned nonlinear distortions of scanning lenses can also be compensated with. Optical design mouroulis major reference works wiley online. A practical guide to lens design focuses on the very detailed practical process of lens design. Tamron nir megapixel lenses utilize cuttingedge optical design technology and advanced low dispersion glass to converge the. The central layer in the longitudinal direction primarily contributes to a bulk of the phase. However the flat field obviously had some sort of issue. Dave boroughs needs to rip out an er department within 2 weeks. The goal is to remove artifacts from 2d images that are caused by variations in the pixeltopixel sensitivity of the detector andor by distortions in the optical path. This design requires that the lens be larger than the scan field driving up the cost and limiting the size of the scan area. A flat field lens tries to compensate so that the focal plane becomes flat rather than the normal fishbowl shape. Over the last 10 to 15 years, the field of optical design has been totally. The earliest anastigmats flattened selection from modern lens design, 2nd edition book.
Thus, a lens cannot have a flat field if it comprises only positive elements. They sport folddown rubber eyeguards so you wont scratch your eyeglasses, and also to provide a. Depending on the final aberration content of the lens design, the optimized image. This letter proposes a technique for designing flat lenses using field transformation ft, as opposed to ray optics ro or transformation optics to. These eyepieces can be used for nighttime astronomy as well as solar observing.
Which of these 2 would be best the 55mm micro nikor or the 60mm. The optimum meniscus corrector chapter 10 the maksutovcassegrain telescope 10. Although the optical correction for field curvature requires the addition of several new lenses to the design, these objectives termed plan or plano are the most common type of objective in use today. You are also interested in flat field macrophotography which simplifies things since all the elements a. This result indicates that, to have a flat field lens, there must be no variation of.
Modern microscopes deal with field curvature by correcting this aberration using specially designed objectives. Conrady in applied optics and optical design and rudolph kingslake in lens design. Among flat fieldzooms, you can consider a vivitar series 1 90180mm f4. Fundamental optical formulae book chapter iopscience. Steven pointed out that the 40mm dx macro is also a flat field lens.
The flood of disorganized communication causes confusion, mistakes, and rework. In this paper, we propose a novel technique to design flat fresnel lens to achieve big concentration ratio, high uniform irradiance distribution while keeping fnumber small using both refraction and total internal reflection tir phenomena. Adding a planoconvex converging lens before curved petzval image surface, according to flatfield condition, regardless of lens thickness, we can write r f the radius of curvature of the planoconvex lens is r f n. This lens is often removed for visual work to reduce the number of lens elements in the telescope. With fieldlens, each house got to substantial completion 30 days ahead of schedule. Field curvature is seldom totally eliminated, but it. Different versions of the class of lenses are presented and can be used to form a practical startingpoint base for many types of lens. Modern lens design mcgrawhill professional engineering, warren j. Most of the worlds fastest lenses today are derivatives of the planar design, including. The term is also used to refer to other lenses that provide a negative index of refraction. Experience breathtaking clarity with new flat field lens technology and phase correction coated prism watch colors pop like mother nature designed them. The idea of extending the depth of focus while keeping the focal spot small increases the interaction of the source field with the object as well as. Flatfield apo refractor telescopes for astrophotography apo refractor telescopes with integrated field corrector combines the advantages of a good appochromatic refractor telescope with a very expensive apo telephoto lens. In recent years, flat lenses based on metasurfaces were also demonstrated.
Agenas guide to focal reducers agena astroproducts. To obtain sharp imaging on a flat surface there must be neither astigmatism. In reply to flowderf apr 20, 2011 the sigma 1224mm a fullframe lens is well known to have extremely low distortion. Im looking for a flat field lens for photographing my painting and drawings. It is a standard calibration procedure in everything from pocket digital cameras to giant.
For example, the field of view fov of a camera and lens combination is an. It is possible to design a flatfield schmidtcassegrain, but these are typically not compact designs and so are only occasionally. It is this type of lens that is most commonly used in corrective lenses. A comprehensive guide to camera lens design and zeiss. During that call, i specifically asked steve about flat field since nikons 60mm macro lens is well known to be a flat field macro, which means the focus plane itself is flat. The structural aberration coefficients do not depend on the field of view, the optical speed. What camera lens would be best for photographing print work. Petzval field curvature, named for joseph petzval, describes the optical aberration in which a. This title is directed primarily towards health care professionals outside of the united states. Smith, and optical system design robert fischer, introduction to lens design. Field guide to lens design 2012 bentley publications. Talyor that designed a flat field lens design with conventional glass. Introduction to lens design by jose sasian september 2019. Because of its large flat field over a wide angle of view and its slow f16 aperture requiring twenty to thirty.