However, a very large amount of residual color aberration known as secondary spectrum still remains. An apochromatic telescope has a multi lens setup to eliminate chromatic aberration when stargazing. Achromatic lenses used in a variety of applications such as microscopy. The main determining factors for choosing lenses includes the number of fluorescence colors you may want to detect, the quality of images required, and the working distance distance between sample and the lens. Corrected for both chromatic and spherical aberration, as a lens. An apochromatic lens normally has 3 or more elements. Criteria for color correction derived from the dispersion formulas of hartmann, cauchy, schmidt, conrady, and buchdahl will be discussed, and their application to the design of apochromatic optical systems will be presented. The design of apochromatic systems is difficult because of two problems. I recently published an article in the journal applied optics where i describe a very fast method for selecting optical glasses for the design of an. Apochromatic lens apo if three or more visible wavelengths of light are brought into focus at the same point behind the lens, the lens is known as an apochromat or is called an apochromatic lens.
Manufacturers label lenses as apo according to their own standards, or with many i suspect when they have made more attempt than usual at correction or more cynically as a suffix used in marketing. Its quadruplet lens design includes four highquality glass elements. An apochromat, or apochromatic lens apo, is a photographic or other lens that has better. A refracting telescope also called a refractor is a type of optical telescope that uses a lens as its objective to form an image also referred to a dioptric telescope. The design of achromatic also helps minimize spherical aberrations. In comparison to a singlet lens, or singlet for short, which only consists of a single piece of glass, the additional design freedom provided by using a doublet. Vixen sd103s apochromatic ed refractor with dovetail adapter, tube rings and flip mirror dual speed focuser is available as optional upgrade. Precise machine vision detection for a large object at a finite working distance wd requires that the lens has a high resolution for a large field of view fov. Aug 31, 2011 it is basicaly impossible to make an apochromatic lens of any kind that is faster than f5ish with even the most modern optical glasses. What is teh difference between an apochromatic and achromatic lensescope. This paper presents a novel approach to the design of such apochromatic combinations which automatically minimizes the residual chromatic aberration over a specific wavelength range. What is apo and what are the real apo lenses on the market. Apochromatic refractor lenses are designed so that at least three colors of lights rather than just two reach the same focus.
Barry johnson, in lens design fundamentals second edition, 2010. They are very readable and include a lot of information on the design of specific lens types not found elsewhere, for example, complex apochromatic lenses in the second volume. Our main focus is on how well we center the lenses compared to the mechanical axis. And by midcentury most of the classic lens design forms had already been created. These books are the basis for a two semester graduate course in lens design. Method to design apochromat and superachromat objectives.
That lens featured a rare at that price point apo apochromatic optical design that delivered incredible sharpness and extremely low chromatic aberrations. Specifically, red light is focused farther from the lens than blue light. Design of twoglass for apochromatic optical system raghad ismail ibrahim almustansiryah universitycollege of educationphysics department, baghdad, iraq, abstract. Apochromatic objective lenses are the most highly corrected and are therefore recommended for color. The lenses are centered to within 2 microns of each other and the cell. Malacara, hand book of optical design, 3th edition, usa. I like apochromatic lenses and am trying to get a list of them together. The distance behind the lens at which monochromatic light light of a single wavelength comes to focus varies as a smooth function of the wavelength. The apm 107700 features an ohara fpl 53 super ed element as part of its apm design lens cell. There is a huge difference in price and a small difference in performance according to an experiment i made recently.
The design requirements for a nonfluorite material apochromatic objective lens with a large field and high definition for machine vision detection have been achieved. Apochromatic vs achromatic refractors cloudy nights. While there are many highend manufacturers that offer apochromatic apo lenses, its very difficult to find a full explanation of what it is to a t. The strict definition of apochromatism is having three wavelengths of light focusing to the same point. Achromatic lenses are corrected to bring two wavelengths typically red and blue into focus on the same plane. Modern lens design mcgrawhill professional engineering smith, warren on. Also, im looking at this beauty, because it is near my budget. Common microscope objective lenses include achromatic, plan achromatic, fluorite, plan fluorite, apochromatic and plan apochromatic lens.
Rudolf kingslake 19032003 is widely considered to be the father of lens design in the united states. Oct 14, 2010 apochromatic vs achromatic refractor people should think twice before purchasing an apochromatic refractor as opposed to an achromatic telescope. This section details the optical design and inherent aberrations of refracting telescopes. Achromatic lens is used to minimize or eliminate chromatic aberration.
Books on optics eckhardt optics books we recommend. Not igoring you advice in the above post just querying. A truly highend colour corrected 3 lens air spaced apochromatic refractor. Therefore, this book can be used with any lens design software. Primalucelab airy ed72 doublet apochromatic refractor. Precision applied products 140 mm f6 apochromatic tube assembly. The fourelement design provides excellent colour correction and ensures pinsharp, highbrilliance images of the night sky. Achromatic and apochromatic refractor designs starizona.
A simple lens focuses different wavelengths of light to different points. Search the worlds most comprehensive index of fulltext books. Achromatic lens achromatic lenses achromat edmund optics. Is that simply because it is a doublet and not triplet lens design. Apochromatic designs of lens systems utilizing two optical materials are. This combination of glass, lenses, and coatings virtually eliminates chromatic and. The 107700 was the result of a long development period. Hannfried zugge, group manager of the carl zeiss optical design department explains more about this fascinating topic. Make an apochromatic telescope, from a pcx lens surplus shed 150 4000mm. Introduction to lens design by jose sasian september 2019. The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses.
Apochromatic objectives are constructed by combining three lenses made of different materials with properly chosen powers and dispersions. The optical glass manufacturers offer a wide range of. I recently published an article in the journal applied optics where i describe a very fast method for selecting optical glasses for the design of an apochromatic lens with a large field of view 1. Osa design of apochromatic lens with large field and high. In a single lens setup, blue light is focussed closer to the lens and it has a shorter focal length. This normally requires a third lens element in the objective. The simplest way to reduce chromatic aberration is to increase the focal length of the lens system whenever possible, so the effect is less prominent in relation to the image location. Design of twoglass for apochromatic optical system raghad. They should not have longitudinal ca when shot wide open. The normal configuration is a positive, lowdispersion crown, combined with two highdispersion flints, one negative and one positive.
An apochromat, or apochromatic lens apo, is a photographic or other lens that has better correction of chromatic and spherical aberration than the much more common achromat lenses. The most common type of achromat is the achromatic doublet, which is composed of two individual lenses made from glasses with different amounts of dispersion. Of course the practice of lens design today is radically different from what it was in the 1940s and 1950s. For a more basic overview of this design please see therefractors page. An apochromat, or apochromatic lens, is a photographic or other lens that has better correction of chromatic and spherical aberration than the much more common achromat lenses.
Explore scientific 102mm f7 ed apochromatic triplet. A method of glass selection for apochromatic optical systems with reduced. If youve seen an inexpensive lens that uses apo in the title ahem, sigma, then you know it probably isnt a true apochromatic lens. Explore scientific instruction booklet for triplet refractors the explore scientific 102mm f7 airspaced triplet ed apo telescope made wired magazines wish list for cool gifts and is a perfect instrument for demanding wide field observing and astrophotography. Optical glass compatibility for the design of apochromatic. Model 76147 vixens new improved range of sd super ed refractors have redesigned baffle positions in t. The sophisticated triplet apochromatic lens system delivers highdefinition views across the entire field of viewno color fringing, degradation of resolution or dilution of color fidelity at longer viewing distances. Orion eon mm ed triplet apochromatic refractor telescope.
Plus, no need to use a field flattener for astrophotography, since the lens design already supplies a flat field of view. The chromatic focal shift for an achromatic doublet made out for bk7 and f2. Apochromatic vs achromatic refractor computer physics lab. Compared with a standard lens of identical speed and focal length, an apochromatic apo lens displays considerably better image quality. Let us indulge your curiosities as we get into what an apo lens is, what the benefits are, and how it can make for a better glassing experience. Vixen sd103s apochromatic ed refractor 365astronomy. With modern lens design and careful choice of lens materials, combined lens systems can be designed to offset the dispersion. Conventional periscope optical design has traditionally employed common achromat relay and objective lenses to correct color aberrations. The achromatic lenses originally designed for telescopes can now be found in various optical instruments, including cameras. Automatic and quasiautonomous computational methods and techniques is the first book that interactively describes the newest modern lens design tools. Modern lens design mcgrawhill professional engineering. The airy ed72 apochromatic refractor utilizes a doublet lens design with fpl51 fully multicoated optical glass. Apochromatic designs of lens systems utilizing two optical materials are described.
Achromatic and athermal lenses chapter 7 introduction to lens. Apochromatic designs require optical glasses with special dispersive. The computer program oslo was used to design the work, but the writeups are programneutral. Jan 09, 20 apochromatic is an ideal that no physical lens is likely to achieve.
The airy ed72 apochromatic refractor offers all this along with other firstclass features. An achromatic lens or achromat is a lens that is designed to limit the effects of chromatic and spherical aberration. Chromatic aberration is caused by the difference in wavelength of various colours of light. For the dedicated visual observer or imager seeking a topoftheline instrument to advance their capabilities and enjoyment in the hobby, the orion eon mm triplet ed apochromatic refractor should be on your short list of candidates. You can read more on this subject in this more detailed article on zeiss lenspire. The different wavelengths meet at the same point of focus, effectively eliminating chromatic aberration. This article is from the photographic lenses faq, by david jacobson with numerous contributions by others 31. Michael kidger, fundamental optical design and intermediate optical design. Detailing design methods for a variety of lens forms, this book shows that fixed focus and zoom lenses can be optimized, starting from planeparallel surfaces, in a brief time on a. Apochromatic definition of apochromatic by the free dictionary. To this day, these designs are still the basis of many excellent modern optical systems.