An Introduction to Chromatic Aberration in Refractors
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Panoramas Shoot with the Camera Positioned Vertically As This Will Give the Photo Merging Software More Wriggle-Room in Merging the Images
P a n o r a m a s What is a Panorama? A panoramic photo covers a larger field of view than a “normal” photograph. In general if the aspect ratio is 2 to 1 or greater then it’s classified as a panoramic photo. This sample is about 3 times wider than tall, an aspect ratio of 3 to 1. What is a Panorama? A panorama is not limited to horizontal shots only. Vertical images are also an option. How is a Panorama Made? Panoramic photos are created by taking a series of overlapping photos and merging them together using software. Why Not Just Crop a Photo? • Making a panorama by cropping deletes a lot of data from the image. • That’s not a problem if you are just going to view it in a small format or at a low resolution. • However, if you want to print the image in a large format the loss of data will limit the size and quality that can be made. Get a Really Wide Angle Lens? • A wide-angle lens still may not be wide enough to capture the whole scene in a single shot. Sometime you just can’t get back far enough. • Photos taken with a wide-angle lens can exhibit undesirable lens distortion. • Lens cost, an auto focus 14mm f/2.8 lens can set you back $1,800 plus. What Lens to Use? • A standard lens works very well for taking panoramic photos. • You get minimal lens distortion, resulting in more realistic panoramic photos. • Choose a lens or focal length on a zoom lens of between 35mm and 80mm. -
Chapter 3 (Aberrations)
Chapter 3 Aberrations 3.1 Introduction In Chap. 2 we discussed the image-forming characteristics of optical systems, but we limited our consideration to an infinitesimal thread- like region about the optical axis called the paraxial region. In this chapter we will consider, in general terms, the behavior of lenses with finite apertures and fields of view. It has been pointed out that well- corrected optical systems behave nearly according to the rules of paraxial imagery given in Chap. 2. This is another way of stating that a lens without aberrations forms an image of the size and in the loca- tion given by the equations for the paraxial or first-order region. We shall measure the aberrations by the amount by which rays miss the paraxial image point. It can be seen that aberrations may be determined by calculating the location of the paraxial image of an object point and then tracing a large number of rays (by the exact trigonometrical ray-tracing equa- tions of Chap. 10) to determine the amounts by which the rays depart from the paraxial image point. Stated this baldly, the mathematical determination of the aberrations of a lens which covered any reason- able field at a real aperture would seem a formidable task, involving an almost infinite amount of labor. However, by classifying the various types of image faults and by understanding the behavior of each type, the work of determining the aberrations of a lens system can be sim- plified greatly, since only a few rays need be traced to evaluate each aberration; thus the problem assumes more manageable proportions. -
Making Your Own Astronomical Camera by Susan Kern and Don Mccarthy
www.astrosociety.org/uitc No. 50 - Spring 2000 © 2000, Astronomical Society of the Pacific, 390 Ashton Avenue, San Francisco, CA 94112. Making Your Own Astronomical Camera by Susan Kern and Don McCarthy An Education in Optics Dissect & Modify the Camera Loading the Film Turning the Camera Skyward Tracking the Sky Astronomy Camp for All Ages For More Information People are fascinated by the night sky. By patiently watching, one can observe many astronomical and atmospheric phenomena, yet the permanent recording of such phenomena usually belongs to serious amateur astronomers using moderately expensive, 35-mm cameras and to scientists using modern telescopic equipment. At the University of Arizona's Astronomy Camps, we dissect, modify, and reload disposed "One- Time Use" cameras to allow students to study engineering principles and to photograph the night sky. Elementary school students from Silverwood School in Washington state work with their modified One-Time Use cameras during Astronomy Camp. Photo courtesy of the authors. Today's disposable cameras are a marvel of technology, wonderfully suited to a variety of educational activities. Discarded plastic cameras are free from camera stores. Students from junior high through graduate school can benefit from analyzing the cameras' optics, mechanisms, electronics, light sources, manufacturing techniques, and economics. Some of these educational features were recently described by Gene Byrd and Mark Graham in their article in the Physics Teacher, "Camera and Telescope Free-for-All!" (1999, vol. 37, p. 547). Here we elaborate on the cameras' optical properties and show how to modify and reload one for astrophotography. An Education in Optics The "One-Time Use" cameras contain at least six interesting optical components. -
Ground-Based Photographic Monitoring
United States Department of Agriculture Ground-Based Forest Service Pacific Northwest Research Station Photographic General Technical Report PNW-GTR-503 Monitoring May 2001 Frederick C. Hall Author Frederick C. Hall is senior plant ecologist, U.S. Department of Agriculture, Forest Service, Pacific Northwest Region, Natural Resources, P.O. Box 3623, Portland, Oregon 97208-3623. Paper prepared in cooperation with the Pacific Northwest Region. Abstract Hall, Frederick C. 2001 Ground-based photographic monitoring. Gen. Tech. Rep. PNW-GTR-503. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 340 p. Land management professionals (foresters, wildlife biologists, range managers, and land managers such as ranchers and forest land owners) often have need to evaluate their management activities. Photographic monitoring is a fast, simple, and effective way to determine if changes made to an area have been successful. Ground-based photo monitoring means using photographs taken at a specific site to monitor conditions or change. It may be divided into two systems: (1) comparison photos, whereby a photograph is used to compare a known condition with field conditions to estimate some parameter of the field condition; and (2) repeat photo- graphs, whereby several pictures are taken of the same tract of ground over time to detect change. Comparison systems deal with fuel loading, herbage utilization, and public reaction to scenery. Repeat photography is discussed in relation to land- scape, remote, and site-specific systems. Critical attributes of repeat photography are (1) maps to find the sampling location and of the photo monitoring layout; (2) documentation of the monitoring system to include purpose, camera and film, w e a t h e r, season, sampling technique, and equipment; and (3) precise replication of photographs. -
High-Quality Computational Imaging Through Simple Lenses
High-Quality Computational Imaging Through Simple Lenses Felix Heide1, Mushfiqur Rouf1, Matthias B. Hullin1, Bjorn¨ Labitzke2, Wolfgang Heidrich1, Andreas Kolb2 1University of British Columbia, 2University of Siegen Fig. 1. Our system reliably estimates point spread functions of a given optical system, enabling the capture of high-quality imagery through poorly performing lenses. From left to right: Camera with our lens system containing only a single glass element (the plano-convex lens lying next to the camera in the left image), unprocessed input image, deblurred result. Modern imaging optics are highly complex systems consisting of up to two pound lens made from two glass types of different dispersion, i.e., dozen individual optical elements. This complexity is required in order to their refractive indices depend on the wavelength of light differ- compensate for the geometric and chromatic aberrations of a single lens, ently. The result is a lens that is (in the first order) compensated including geometric distortion, field curvature, wavelength-dependent blur, for chromatic aberration, but still suffers from the other artifacts and color fringing. mentioned above. In this paper, we propose a set of computational photography tech- Despite their better geometric imaging properties, modern lens niques that remove these artifacts, and thus allow for post-capture cor- designs are not without disadvantages, including a significant im- rection of images captured through uncompensated, simple optics which pact on the cost and weight of camera objectives, as well as in- are lighter and significantly less expensive. Specifically, we estimate per- creased lens flare. channel, spatially-varying point spread functions, and perform non-blind In this paper, we propose an alternative approach to high-quality deconvolution with a novel cross-channel term that is designed to specifi- photography: instead of ever more complex optics, we propose cally eliminate color fringing. -
As the Dome of Twilight Sinks Below The
As the dome of twilight sinks below the horizon, a mechanical corps de ballet starts a slow-motion pirouette with each dancer keeping the unblinking eye of a telescope locked on a single spot in the heavens. Shutters open and ancient photons, ending a journey that may have started before the earth was born, collide with sensors that store an electron to mark that photon's arrival. With the dance in motion the directors sit back to watch the show; another imaging session has begun... Image by Marcus Stevens A Full and Proper Kit An introduction to the gear of astro-photography The young recruit is silly – 'e thinks o' suicide; 'E's lost his gutter-devil; 'e 'asn't got 'is pride; But day by day they kicks him, which 'elps 'im on a bit, Till 'e finds 'isself one mornin' with a full an' proper kit. Rudyard Kipling Like the young recruit in Kipling's poem 'The 'Eathen', a deep-sky imaging beginner starts with little in the way of equipment or skill. With 'older' imagers urging him onward, providing him with the benefit of the mistakes that they had made during their journey and allowing him access to the equipment they've built or collected, the newcomer gains the 'equipment' he needs, be it gear or skills, to excel at the art. At that time he has acquired a 'full and proper kit' and ceases to be a recruit. This paper is a discussion of hardware, software, methods and actions that a newcomer might find useful. It is not meant to be an in-depth discussion of all forms of astro-photography; that would take many books and more knowledge than I have available. -
AG-AF100 28Mm Wide Lens
Contents 1. What change when you use the different imager size camera? 1. What happens? 2. Focal Length 2. Iris (F Stop) 3. Flange Back Adjustment 2. Why Bokeh occurs? 1. F Stop 2. Circle of confusion diameter limit 3. Airy Disc 4. Bokeh by Diffraction 5. 1/3” lens Response (Example) 6. What does In/Out of Focus mean? 7. Depth of Field 8. How to use Bokeh to shoot impressive pictures. 9. Note for AF100 shooting 3. Crop Factor 1. How to use Crop Factor 2. Foal Length and Depth of Field by Imager Size 3. What is the benefit of large sensor? 4. Appendix 1. Size of Imagers 2. Color Separation Filter 3. Sensitivity Comparison 4. ASA Sensitivity 5. Depth of Field Comparison by Imager Size 6. F Stop to get the same Depth of Field 7. Back Focus and Flange Back (Flange Focal Distance) 8. Distance Error by Flange Back Error 9. View Angle Formula 10. Conceptual Schema – Relationship between Iris and Resolution 11. What’s the difference between Video Camera Lens and Still Camera Lens 12. Depth of Field Formula 1.What changes when you use the different imager size camera? 1. Focal Length changes 58mm + + It becomes 35mm Full Frame Standard Lens (CANON, NIKON, LEICA etc.) AG-AF100 28mm Wide Lens 2. Iris (F Stop) changes *distance to object:2m Depth of Field changes *Iris:F4 2m 0m F4 F2 X X <35mm Still Camera> 0.26m 0.2m 0.4m 0.26m 0.2m F4 <4/3 inch> X 0.9m X F2 0.6m 0.4m 0.26m 0.2m Depth of Field 3. -
Glossary of Lens Terms
GLOSSARY OF LENS TERMS The following three pages briefly define the optical terms used most frequently in the preceding Lens Theory Section, and throughout this catalog. These definitions are limited to the context in which the terms are used in this catalog. Aberration: A defect in the image forming capability of a Convex: A solid curved surface similar to the outside lens or optical system. surface of a sphere. Achromatic: Free of aberrations relating to color or Crown Glass: A type of optical glass with relatively low Lenses wavelength. refractive index and dispersion. Airy Pattern: The diffraction pattern formed by a perfect Diffraction: Deviation of the direction of propagation of a lens with a circular aperture, imaging a point source. The radiation, determined by the wave nature of radiation, and diameter of the pattern to the first minimum = 2.44 λ f/D occurring when the radiation passes the edge of an Where: obstacle. λ = Wavelength Diffraction Limited Lens: A lens with negligible residual f = Lens focal length aberrations. D = Aperture diameter Dispersion: (1) The variation in the refractive index of a This central part of the pattern is sometimes called the Airy medium as a function of wavelength. (2) The property of an Filters Disc. optical system which causes the separation of the Annulus: The figure bounded by and containing the area monochromatic components of radiation. between two concentric circles. Distortion: An off-axis lens aberration that changes the Aperture: An opening in an optical system that limits the geometric shape of the image due to a variation of focal amount of light passing through the system. -
A Guide to Smartphone Astrophotography National Aeronautics and Space Administration
National Aeronautics and Space Administration A Guide to Smartphone Astrophotography National Aeronautics and Space Administration A Guide to Smartphone Astrophotography A Guide to Smartphone Astrophotography Dr. Sten Odenwald NASA Space Science Education Consortium Goddard Space Flight Center Greenbelt, Maryland Cover designs and editing by Abbey Interrante Cover illustrations Front: Aurora (Elizabeth Macdonald), moon (Spencer Collins), star trails (Donald Noor), Orion nebula (Christian Harris), solar eclipse (Christopher Jones), Milky Way (Shun-Chia Yang), satellite streaks (Stanislav Kaniansky),sunspot (Michael Seeboerger-Weichselbaum),sun dogs (Billy Heather). Back: Milky Way (Gabriel Clark) Two front cover designs are provided with this book. To conserve toner, begin document printing with the second cover. This product is supported by NASA under cooperative agreement number NNH15ZDA004C. [1] Table of Contents Introduction.................................................................................................................................................... 5 How to use this book ..................................................................................................................................... 9 1.0 Light Pollution ....................................................................................................................................... 12 2.0 Cameras ................................................................................................................................................ -
Choosing Digital Camera Lenses Ron Patterson, Carbon County Ag/4-H Agent Stephen Sagers, Tooele County 4-H Agent
June 2012 4H/Photography/2012-04pr Choosing Digital Camera Lenses Ron Patterson, Carbon County Ag/4-H Agent Stephen Sagers, Tooele County 4-H Agent the picture, such as wide angle, normal angle and Lenses may be the most critical component of the telescopic view. camera. The lens on a camera is a series of precision-shaped pieces of glass that, when placed together, can manipulate light and change the appearance of an image. Some cameras have removable lenses (interchangeable lenses) while other cameras have permanent lenses (fixed lenses). Fixed-lens cameras are limited in their versatility, but are generally much less expensive than a camera body with several potentially expensive lenses. (The cost for interchangeable lenses can range from $1-200 for standard lenses to $10,000 or more for high quality, professional lenses.) In addition, fixed-lens cameras are typically smaller and easier to pack around on sightseeing or recreational trips. Those who wish to become involved in fine art, fashion, portrait, landscape, or wildlife photography, would be wise to become familiar with the various types of lenses serious photographers use. The following discussion is mostly about interchangeable-lens cameras. However, understanding the concepts will help in understanding fixed-lens cameras as well. Figures 1 & 2. Figure 1 shows this camera at its minimum Lens Terms focal length of 4.7mm, while Figure 2 shows the110mm maximum focal length. While the discussion on lenses can become quite technical there are some terms that need to be Focal length refers to the distance from the optical understood to grasp basic optical concepts—focal center of the lens to the image sensor. -
Zemax, LLC Getting Started with Opticstudio 15
Zemax, LLC Getting Started With OpticStudio 15 May 2015 www.zemax.com [email protected] [email protected] Contents Contents 3 Getting Started With OpticStudio™ 7 Congratulations on your purchase of Zemax OpticStudio! ....................................... 7 Important notice ......................................................................................................................... 8 Installation .................................................................................................................................... 9 License Codes ........................................................................................................................... 10 Network Keys and Clients .................................................................................................... 11 Troubleshooting ...................................................................................................................... 11 Customizing Your Installation ............................................................................................ 12 Navigating the OpticStudio Interface 13 System Explorer ....................................................................................................................... 16 File Tab ........................................................................................................................................ 17 Setup Tab ................................................................................................................................... 18 Analyze -
Topic 3: Operation of Simple Lens
V N I E R U S E I T H Y Modern Optics T O H F G E R D I N B U Topic 3: Operation of Simple Lens Aim: Covers imaging of simple lens using Fresnel Diffraction, resolu- tion limits and basics of aberrations theory. Contents: 1. Phase and Pupil Functions of a lens 2. Image of Axial Point 3. Example of Round Lens 4. Diffraction limit of lens 5. Defocus 6. The Strehl Limit 7. Other Aberrations PTIC D O S G IE R L O P U P P A D E S C P I A S Properties of a Lens -1- Autumn Term R Y TM H ENT of P V N I E R U S E I T H Y Modern Optics T O H F G E R D I N B U Ray Model Simple Ray Optics gives f Image Object u v Imaging properties of 1 1 1 + = u v f The focal length is given by 1 1 1 = (n − 1) + f R1 R2 For Infinite object Phase Shift Ray Optics gives Delta Fn f Lens introduces a path length difference, or PHASE SHIFT. PTIC D O S G IE R L O P U P P A D E S C P I A S Properties of a Lens -2- Autumn Term R Y TM H ENT of P V N I E R U S E I T H Y Modern Optics T O H F G E R D I N B U Phase Function of a Lens δ1 δ2 h R2 R1 n P0 P ∆ 1 With NO lens, Phase Shift between , P0 ! P1 is 2p F = kD where k = l with lens in place, at distance h from optical, F = k0d1 + d2 +n(D − d1 − d2)1 Air Glass @ A which can be arranged to|giv{ze } | {z } F = knD − k(n − 1)(d1 + d2) where d1 and d2 depend on h, the ray height.