Us7920339b2 method and apparatus providing singlet wafer. Flattens the field in addition to reducing the effective focal length for fast, superior quality astroimaging operations. 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. Design requirements of a particular system require the scanning spot to have a specific intensity. The process of designing lenses is both an art and a science. Countering the blurred effect typically rendered by the curvature of conventional lens elements, field flattener lenses help deliver a sharp, lowdistortion image across the entire field of view. Lens design was more conceptual in the early days of lens design since computational lens design had not been developed. Methods and apparatus to correct a curved petzval focusing surface to a plane using a convex lens, a concave lens, and a space arranged between the curved side of the convex lens and the curved side of the concave lens. Field flattener lenses counteract the petzval field curvature of an optical system.
And conveniently, its one thats easy to understand even without the coefficients. Use with a dslr requires a standard m42 tring sold separately for the camera. There are also some nonreducing field flatteners available for. Lens design opti 517 syllabus university of arizona. The first lens used for photography was designed in 1812 by the english scientist w. A field flattener lens made in silica with the front and the rear surfaces being aspherical field flattener are different for each channel. Petzval portrait lens and field flattener phase, hologram, and sweatt models rapid rectilinear, meniscus and landscape lens protar and optimization hints newachromat and schroeder lens cooke triplet and as telecentric lens. Field flattener lenses counteract the petzval field curvaturepetzval field. In a twomirror system, the lens field flattener is of negative power, with both. Explore scientific ed102apo reducerfield flattener posted in refractors.
Threadon field flattener adaptor, used to install the field flatteneron the focusers drawtube. Field flattener techniques for reduction of aberrations. To start off, we look at classic lens design forms in the dawn of lens design. Thoroughly revised and expanded to reflect the substantial changes in the field since its publication in 1978 strong emphasis on how to effectively use software design packages, indispensable to todays lens. Ray tracing and aberration theory was invented during this period. Wollaston and chevalier landscape lenses, a 10x microscope objective, the rapid rectilinear and celor lenses, cooke triplet and petzval portrait lenses, and a telephoto lens. Fully contributes to petzval but not to spherical, coma, or astigmatism. Lens design fundamentals download ebook pdf, epub, tuebl. Its only remaining primary aberration is strong field curvature. Field guide to lens design 2012 bentley publications. I think i have finished a design of a fileld flattener for it when done, ill post all about it, but i have a question for resident optical experts before i call it done. Coma and astigmatism are corrected by the relative lens powers, thicknesses, and spacing between the doublet and the positive lens.
Optical engineers working in lens design will find this book an invaluable guide to lens design in traditional and emerging areas of application. Optical design with the schmidt concept telescopes and. This 63 distance is called the field flattener back focus. The orion field flattener for short refractors is compatible with 2 focuser drawtubes and is conveniently threaded for use with 2 filters. Lens design fundamentals download ebook pdf, epub, tuebl, mobi. While realising a wide field of view, the field flattener lens system assures a sharp and clear view all the way to the lens periphery. Field lenses are placed at or near an image location for the purpose of optically. Conrady in applied optics and optical design and rudolph kingslake in lens design. Define the three field points for initial field angles of 0, 3 and 5. It adds impressive building blocks to the foundation established by a. The invention of the camera in the early 19th century led to an array of lens designs intended for photography.
The method and apparatus may also include a fresnel lens arranged between the concave lens and a pixel array. Installing the field flattener and a dslr digital single lens reflex camera note. The ffedapo01 is designed to work with explore scientifics achromatic doublet series dar,essential series and fcd100 series telescopes with diameters of 80 mm, 102 mm and 127 mm. Coma and astigmatism are corrected by the relative lens pow ers, thicknesses, and spacing. Schmidt camera field flattener good example for the use of a singlelens flattener is the schmidt camera, which is exclusively a photographic instrument. Lens design fundamentals, second edition, is the most comprehensive treatise to be published on the subject of lens design. The field flattener is everyones most common example of this negative power element, that reduces the field curvature. Design for near and distant viewing distances is essentially identical. The percival philosophy is similar to that used in modern spectacle lens design.
The object in designing a field flattening lens is to create a lens that shifts the focal points of the petzval surface to lie in the same plane. The fieldflattener lens seems to have improved the image quality. Design, assembly, and testing of an objective lens for a free. Smith, modern lens design, a resource manual, mcgraw hill.
Orion field flattener for short refractors orion telescopes. Sharp, clear images to the lens periphery, thanks to nikons field flattener lens system. Inside the box the 6mm ring spacer 3 is assembled with the field flattener body 2. Field flattening 201203 herbert gross winter term 20.
The rings are designed to provide 63mm of back focus with any dslr camera. Field flatteners are designed with the goal to exactly counter the inherent inward curvature and bring the star size down by a factor of about 50. Page 9 field of viewreal field of viewapparent field of viewfield of view at 1. Skills acquired include thin lens predesign, first and third order analytical methods, and computerbased design using zemax. When assembled, the two parts may look as if there were only one piece. Bulges and constrictions consider the cooke triplet and lenses for microlithography. Explore scientific ed102apo reducerfield flattener. Slhkuh kuum u iihi 2 sheetssheet l signal q source c.
The reader is urged to follow the logic of these examples and be. Field flattener subaperture corrector amateur telescope optics. By default, field flattener lens faces image with its flat side, and the sign of its curved surface is. Hotech sca field flattener lowest price guaranteed opt. I still havent finished the complete design of my 6 ahcro binoscope, but im getting there. These classic lenses may look simple given the more complex lens designs we have today. Installing the field flattener and a dslr digital singlelens reflex camera note. This is a twoelement lens system that corrects the field of the ritcheychretien optical design. Page 11 8x32se cf10x42se cf12x50se cf all lenses and prisms are multilayer coated for the brightest images sharp, clear images to the lens periphery, thanks to nikons original field flattener lens and eyepiece design higheyepoint design for a clear field of view. The design of a lens being combined with this concentric field flattener element should include the aberrations resulting from a glass plate having a thickness equal to the distance between the plano surfaces of the concentric field flattener lens. Reduces the focal length of meade 115 mm and mm series 6000 apo refractor telescopes by a factor of 0. Full textpdf journal of the korean physical society.
Field of view at 1,000 meters is the width of the visible area at a distance of 1,000 meters, which can be seen without moving the binoculars. Field flattener lens the 8x20 is binoculars uses a field flattening lens element to provide edgetoedge sharpness for vivid images. 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. Design, assembly, and testing of an objective lens for a. Field flattener lens system forms sharp images all the way to the periphery curvature of field is an aberration that occurs when focusing on the centre of the field of view causing the periphery to go out of focus or vice versa. The hotech sca field flattener is fully multicoated on twoelement lens allowing the most efficient light transmission without sacrificing the precious collected light from your telescope. Distortion in this lens form can be controlled using the shape of the field flattener and was adjusted to provide the required fsino mapping. Anyone got a recommendation for one which works with the scope and a ccd camera like the qsi 660 wsg8 thanks. The types of optical systems in a lens designers toolbox. Chapter 1 handbook of optics photonics research group. Lens design fundamentals, kingslake, rudolf, johnson, r. This field flattener is an excellent choice for cameras with cropped sensors apsc and smaller. Higheyepoint design provides a clear field of view even for eyeglass wearers waterproof up to 1m3.
Reduces the focal length of meade 115 mm and mm series 6000 apo refractor telescopes. Field flattener lenses in binoculars improve edge sharpness and lower the distortion. 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. Skills acquired include thin lens pre design, first and third order analytical methods, and computerbased design using zemax. Field flattener lens is a type of lens used in modern binocular designs and in astronomic telescopes. Field lens flattener a field lens near to the image plane can help to correct a system for field curvature. Some focal reducers also act as a field flattener to significantly reduce the field curvature in all schmidtcassegrains and most refractors that causes stars to be out of focus at the edge of the field when the scope is sharply focused at the center. Backfocus of 55mm is required to achieve proper distance for use with ccd imagers. Fieldflattener lens system nikons fieldflattener lens system technology minimises curvature of field aberrations that occur when focusing on the centre of the field of view causing the periphery to go out of focus and vice versa and delivers sharper, clearer images all the way to the lens periphery. This book holds a unique place in the optics literature.
Field flattener lenses in binoculars improve edge sharpness. Field guide to lens design julie bentley, craig olson. This field flattener is fully multicoated on twoelement lens allowing the most efficient light transmission without sacrificing the precious collected light from your telescope. A ring spacer of 8mm is attached to the field flattener body. The field flattener lens mount design provides a nominal clearance between the lens and frames at operating temperature to accommodate material coefficient of thermal expansion differences and manufacturing tolerances without overstressing the lens. By examining the examples of relatively simple lens designs, it is actually easier to dissect why the lens designs are the way they are. So ive shown a ray trace here of a 2 millimeter telescope. In order to get the premium results the field flattener for esprit 100 can deliver the distance between the last lenses to the sensor should be exactly mm. Page 1 of 2 designing a field flattener and maybe reducing eyepiece astigmatism. Hotech sca field flattener the hotech sca field flattener is fully multicoated on twoelement lens allowing the most efficient light transmission without sacrificing the precious collected light from your telescope. Also there is little contribution to optical power.
Consider inserting a pane of glass in a focusing beam. Field flattener lens is a type of lens used in modern binocular designs e. Design, assembly, and testing of an objective university of arizona. Wollaston and chevalier landscape lenses, a 10x microscope objective, the rapid rectilinear and celor lenses, cooke triplet and petzval portrait lenses, and a. Page 9 field of viewreal field of viewapparent field of view field of view at 1. The problems of photographic lens design, creating a lens for a task that would cover a large, flat image plane, were well known even before the invention of photography due to the development of lenses to work with the focal plane of the camera obscura.
For the schmidt camera, field flattener lens is positive, with the radius. The air concentric field flattener lens has a manufacturing advantage over the form shown in. It will not provide a flat field when used with fullframe cameras. Tangential and sagittal sharp image shell depending on the azimuth. In other words, the function of a field flattener lens is to counter the fieldangle dependence of the focal length of a system. The lens can have an additional field flattener at the back, to.