Optics for Birding – the Basics
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Breaking Down the “Cosine Fourth Power Law”
Breaking Down The “Cosine Fourth Power Law” By Ronian Siew, inopticalsolutions.com Why are the corners of the field of view in the image captured by a camera lens usually darker than the center? For one thing, camera lenses by design often introduce “vignetting” into the image, which is the deliberate clipping of rays at the corners of the field of view in order to cut away excessive lens aberrations. But, it is also known that corner areas in an image can get dark even without vignetting, due in part to the so-called “cosine fourth power law.” 1 According to this “law,” when a lens projects the image of a uniform source onto a screen, in the absence of vignetting, the illumination flux density (i.e., the optical power per unit area) across the screen from the center to the edge varies according to the fourth power of the cosine of the angle between the optic axis and the oblique ray striking the screen. Actually, optical designers know this “law” does not apply generally to all lens conditions.2 – 10 Fundamental principles of optical radiative flux transfer in lens systems allow one to tune the illumination distribution across the image by varying lens design characteristics. In this article, we take a tour into the fascinating physics governing the illumination of images in lens systems. Relative Illumination In Lens Systems In lens design, one characterizes the illumination distribution across the screen where the image resides in terms of a quantity known as the lens’ relative illumination — the ratio of the irradiance (i.e., the power per unit area) at any off-axis position of the image to the irradiance at the center of the image. -
Geometrical Irradiance Changes in a Symmetric Optical System
Geometrical irradiance changes in a symmetric optical system Dmitry Reshidko Jose Sasian Dmitry Reshidko, Jose Sasian, “Geometrical irradiance changes in a symmetric optical system,” Opt. Eng. 56(1), 015104 (2017), doi: 10.1117/1.OE.56.1.015104. Downloaded From: https://www.spiedigitallibrary.org/journals/Optical-Engineering on 11/28/2017 Terms of Use: https://www.spiedigitallibrary.org/terms-of-use Optical Engineering 56(1), 015104 (January 2017) Geometrical irradiance changes in a symmetric optical system Dmitry Reshidko* and Jose Sasian University of Arizona, College of Optical Sciences, 1630 East University Boulevard, Tucson 85721, United States Abstract. The concept of the aberration function is extended to define two functions that describe the light irra- diance distribution at the exit pupil plane and at the image plane of an axially symmetric optical system. Similar to the wavefront aberration function, the irradiance function is expanded as a polynomial, where individual terms represent basic irradiance distribution patterns. Conservation of flux in optical imaging systems is used to derive the specific relation between the irradiance coefficients and wavefront aberration coefficients. It is shown that the coefficients of the irradiance functions can be expressed in terms of wavefront aberration coefficients and first- order system quantities. The theoretical results—these are irradiance coefficient formulas—are in agreement with real ray tracing. © 2017 Society of Photo-Optical Instrumentation Engineers (SPIE) [DOI: 10.1117/1.OE.56.1.015104] Keywords: aberration theory; wavefront aberrations; irradiance. Paper 161674 received Oct. 26, 2016; accepted for publication Dec. 20, 2016; published online Jan. 23, 2017. 1 Introduction the normalized field H~ and aperture ρ~ vectors. -
How to Choose and Use Birding Optics
Blackburnian Warbler In association with Chestnut-sided Warbler CONTENTS Birding Optics 101 . 2 Optics Terms . 3 How Binoculars Work . 6 All About Spotting Scopes . 10 Top 10 Tips for Purchasing Your First Optics . 14 Adjusting Your Birding Optics . 18 Become a Birder in 5 Simple Steps . 22 Identifying Birds . 24 Three Tips for IDing Birds . 26 Traveling With Optics . 28 BIRDING OPTICS 101 No bird watcher’s toolkit is complete without optics, which means binoculars or a spotting scope . While you can bird without the magnifying power of optics, you won’t always get a satisfactory look at the birds, and will likely miss a few IDs . One barrier to entry for aspiring birders is the belief that quality optics are expensive . They can be, but they don’t have to be . Technological and manufacturing advances mean that today’s binoculars and spotting scopes are more affordable than ever, while still featuring high-end materials . So, where do you begin when selecting your first birding optics? In this guide, we discuss how binoculars and spotting scopes work, so you can select the best optics to enhance your birding experience . Once you’ve made your choice, we’ll teach you how to clean and care for your optics . You will learn to love them, because they are your gateway to discovering flocks’ worth of amazing birds . OPTICS DEFINED: WHAT YOU SEE IS WHAT YOU GET The vast majority of birders use binoculars—also known as “binos,” “binocs,” or “bins” for short . When you hear birders use the term “optics,” they are usually referring to binoculars . -
Photography and Photomontage in Landscape and Visual Impact Assessment
Photography and Photomontage in Landscape and Visual Impact Assessment Landscape Institute Technical Guidance Note Public ConsuDRAFTltation Draft 2018-06-01 To the recipient of this draft guidance The Landscape Institute is keen to hear the views of LI members and non-members alike. We are happy to receive your comments in any form (eg annotated PDF, email with paragraph references ) via email to [email protected] which will be forwarded to the Chair of the working group. Alternatively, members may make comments on Talking Landscape: Topic “Photography and Photomontage Update”. You may provide any comments you consider would be useful, but may wish to use the following as a guide. 1) Do you expect to be able to use this guidance? If not, why not? 2) Please identify anything you consider to be unclear, or needing further explanation or justification. 3) Please identify anything you disagree with and state why. 4) Could the information be better-organised? If so, how? 5) Are there any important points that should be added? 6) Is there anything in the guidance which is not required? 7) Is there any unnecessary duplication? 8) Any other suggeDRAFTstions? Responses to be returned by 29 June 2018. Incidentally, the ##’s are to aid a final check of cross-references before publication. Contents 1 Introduction Appendices 2 Background Methodology App 01 Site equipment 3 Photography App 02 Camera settings - equipment and approaches needed to capture App 03 Dealing with panoramas suitable images App 04 Technical methodology template -
S P O R T O P T I
KENKO-SPORT-OPTICS-2012-1 12.4.6 11:07 AM Page 1 SPORT OPTICS BIRDING SPORTS MARINE OUTDOOR TRAVEL EVENTS ASTRONOMY KENKO-SPORT-OPTICS-2012-1 12.4.6 11:07 AM Page 2 KENKO-SPORT-OPTICS-2012-1 12.4.6 11:07 AM Page 3 In a moment, the breadth and beauty of nature is real, inviting you into its world... The sea, mountains, fields, forests and blue sky... see the full grandeur of nature through our outstanding line of binoculars. RECOMMENDED NEW ITEMS OP 8x32 DH II 8X21 DH SG OP 10x32W DH II 10X25 DH SG BIRDING BINOCULARS For more information, please refer to page 8 For more information, please refer to page 15 KENKO-SPORT-OPTICS-2012-1 12.4.6 11:07 AM Page 4 INDEX As one of the world's largest makers of binoculars, Kenko has the experience and refined manufacturing techniques to produce high-quality, multi-coated and phase-coated glass optics that yield bright, crisp clear viewing under a wide-variety of conditions. You may not know the name, but the Kenko company is an original manufacturer with decades of experience in the precise production of sports optics. THE PRODUCTION PROCESS OF KENKO BINOCULARS INDEX BINOCULARS Kenko - ULTIMATE BIRDING BINOCULARS OP 8x42DH Mark II / OP 10x42DH Mark II, 8x42DH MS / 10x42DH MS . .6 8x32DH MS / 10x32DH MS, 8x25DH / 10x25D . .7 ultra VIEW EX - PREMIUM BIRDING BINOCULARS OP 8x32 DH II / OP 10x32W DH II, OP 8x42 DH ED / OP 10x42 DH ED . .8 OP 8x42 DH II / OP 10x42 DH II, 10x50 DH / 12x50 DH, 8x42 DH / 10x42 DH . -
Telescopes and Binoculars
Continuing Education Course Approved by the American Board of Opticianry Telescopes and Binoculars National Academy of Opticianry 8401 Corporate Drive #605 Landover, MD 20785 800-229-4828 phone 301-577-3880 fax www.nao.org Copyright© 2015 by the National Academy of Opticianry. All rights reserved. No part of this text may be reproduced without permission in writing from the publisher. 2 National Academy of Opticianry PREFACE: This continuing education course was prepared under the auspices of the National Academy of Opticianry and is designed to be convenient, cost effective and practical for the Optician. The skills and knowledge required to practice the profession of Opticianry will continue to change in the future as advances in technology are applied to the eye care specialty. Higher rates of obsolescence will result in an increased tempo of change as well as knowledge to meet these changes. The National Academy of Opticianry recognizes the need to provide a Continuing Education Program for all Opticians. This course has been developed as a part of the overall program to enable Opticians to develop and improve their technical knowledge and skills in their chosen profession. The National Academy of Opticianry INSTRUCTIONS: Read and study the material. After you feel that you understand the material thoroughly take the test following the instructions given at the beginning of the test. Upon completion of the test, mail the answer sheet to the National Academy of Opticianry, 8401 Corporate Drive, Suite 605, Landover, Maryland 20785 or fax it to 301-577-3880. Be sure you complete the evaluation form on the answer sheet. -
Field of View - Wikipedia, the Free Encyclopedia
Field of view - Wikipedia, the free encyclopedia http://en.wikipedia.org/wiki/Field_of_view From Wikipedia, the free encyclopedia The field of view (also field of vision, abbreviated FOV) is the extent of the observable world that is seen at any given moment. In case of optical instruments or sensors it is a solid angle through which a detector is sensitive to electromagnetic radiation. 1 Humans and animals 2 Conversions Horizontal Field of View 3 Machine vision 4 Remote sensing 5 Astronomy 6 Photography 7 Video games 8 See also 9 References In the context of human vision, the term “field of view” is typically used in the sense of a restriction Vertical Field of View to what is visible by external apparatus, like spectacles[2] or virtual reality goggles. Note that eye movements do not change the field of view. If the analogy of the eye’s retina working as a sensor is drawn upon, the corresponding concept in human (and much of animal vision) is the visual field. [3] It is defined as “the number of degrees of visual angle during stable fixation of the eyes”.[4]. Note that eye movements are excluded in the definition. Different animals have different visual fields, depending, among others, on the placement of the eyes. Humans have an almost 180-degree forward-facing horizontal diameter of their visual field, while some birds have a complete or nearly complete 360-degree Angle of view can be measured visual field. The vertical range of the visual field in humans is typically horizontally, vertically, or diagonally. -
Astronomical Binoculars
30˚E 15˚E OWNER’S MANUAL ASTRONOMICAL BINOCULARS ZHUMELL 20X80 SUPERGIANT ASTRONOMICAL BINOCULARS 0˚ 15˚W 75˚W 60˚W 30˚W 45˚W Zhumell customers know that there are plenty of ways to experience the world. They also understand that, however you choose to explore it, the best experience is one that fully immerses you in the world’s most striking details. That’s where our optics products come in. We strive to put high-performance products in the hands of our customers so that they can experience the world up close, with their own eyes. With Zhumell, you get field-tested, precision-crafted optics at the best possible value. So even if you’re just starting out as an amateur birder or astronomer, you don’t have to settle for entry-level products. Zhumell customers enjoy life’s pursuits, hobbies, and adventures in rich, colorful detail- the kind of detail that only high-performance optics can produce. At Zhumell, we design our binoculars, telescopes, and spotting scopes for discerning, price-conscious users who are uncompromising on quality. If you’re looking for accessibly priced optics that will bring your world within reach, you’re looking for Zhumell. Enjoy the view. 2 ENJOYING YOUR ZHUMELL ASTRONOMICAL BINOCULARS 1. Caring For Your Binoculars 2. Using Your Binoculars i. Tripod Mounting ii. Interpupillary Distance iii. Center and Diopter Focus 3. Terrestrial and Astronomical Viewing 4. Astronomical Observation Tips i. Selecting a Viewing Site ii. Seeing and Transparency iii. Dark-Adapting iv. Tracking Celestial Objects 5. Cool Views i. The Moon ii. -
Viewing an Eclipse Safely
ECLIPSES SOLAR an eclipse safely How to observe SOLAR ECLIPSE, OCTOBER 2014, BY LEMAN NORTHWAY Solar eclipses are quite rare and are often a major event. The SOLAR ECLIPSES Moon passes right in front of the Sun, blotting out its disc. Every time a solar eclipse occurs there are various things to look for. However, it is extremely dangerous to just go out and look up. The Sun is so bright that just looking at it can blind you, so you’ll need to prepare beforehand. There are various ways to observe eclipses safely, using both everyday materials and telescopes or binoculars. So read this leaflet Introduction to find out what happens during an eclipse and how you can see all the stages of the event safely. This booklet was written by the Royal Astronomical Society with The Society for Popular Astronomy and is endorsed by the British Astronomical Association The Royal Astronomical The Society for Popular Formed in 1890, the Society, founded in Astronomy is for British Astronomical 1820, encourages and beginners of all ages. Our Association has an promotes the study of aim is to make astronomy international reputation astronomy, solar-system fun, and our magazine, for the quality of science, geophysics and Popular Astronomy, is full its observational closely related branches of information to help and scientific work. of science. you get to know the Membership is open to www.ras.org.uk sky and get involved. We even have a special Young all persons interested in HIGGS-BOSON.COM JOHNSON: PAUL BY D Stargazers section, run by TV’s Lucie Green. -
Optical & Sport Systems
PRODUCT GUIDE No. 46 ◆ 9 •20 7 1 9 4 1 Optical & Sport Systems 3 5 t h Ye a r BINOCULARS TELESCOPES MICROSCOPES OUTDOOR ◆ INDEX BINOCULARS & SPOTTERS SPECS Konus is tradition and innovation. The tradition of an historic and prestigious brand that Konus binoculars and spotting scopes are made with an uncompromising commit- has become a synonymours of uncompromising quality and excellenge in the optics ment to quality at its highest standards. Their superior components ensure the ultimate industry over the last years and is currently distributed in 76 Countries worldwide. viewing experience for every demanding user. Featuring a wide assortment of models The innovation of a creative approach to the market that takes place through the con- with distinctive specifications (compact, zoom, waterproof, etc.), our lines of binoculars stant development of exclusive products with an unique and original style in both their and spotting scopes have become the favourite choice of avid hunters, birdwatchers design and packaging. In the competitive and challenging market of nowadays, Konus and outdoorsmen. is able to offer the ideal solution for every possible need, from Hunting to Birdwatching, from Research to Astonomiy, from Science to Sport. MAGNIFICATION: EYE RELIEF: This is the number of times that an object is being enlarged whi- this is the distance a binocular/spotting scope can be held away le looking at it through a binocular/spotting scope. For example, from the eye and still maintain the full field of view. Long eye BINOCULARS ◆ MAGNIFIERS an object that is 100 yards away will appear like it is 5 yards relief optics reduce eyestrain and are much more comfortable, away if it is observed with a 20x instrument (100 : 20 = 5). -
The Microscope Parts And
The Microscope Parts and Use Name:_______________________ Period:______ Historians credit the invention of the compound microscope to the Dutch spectacle maker, Zacharias Janssen, around the year 1590. The compound microscope uses lenses and light to enlarge the image and is also called an optical or light microscope (vs./ an electron microscope). The simplest optical microscope is the magnifying glass and is good to about ten times (10X) magnification. The compound microscope has two systems of lenses for greater magnification, 1) the ocular, or eyepiece lens that one looks into and 2) the objective lens, or the lens closest to the object. Before purchasing or using a microscope, it is important to know the functions of each part. Eyepiece Lens: the lens at the top that you look through. They are usually 10X or 15X power. Tube: Connects the eyepiece to the objective lenses Arm: Supports the tube and connects it to the base. It is used along with the base to carry the microscope Base: The bottom of the microscope, used for support Illuminator: A steady light source (110 volts) used in place of a mirror. Stage: The flat platform where you place your slides. Stage clips hold the slides in place. Revolving Nosepiece or Turret: This is the part that holds two or more objective lenses and can be rotated to easily change power. Objective Lenses: Usually you will find 3 or 4 objective lenses on a microscope. They almost always consist of 4X, 10X, 40X and 100X powers. When coupled with a 10X (most common) eyepiece lens, we get total magnifications of 40X (4X times 10X), 100X , 400X and 1000X. -
Investigation of Driver's FOV and Related Ergonomics Using Laser Shadowgraphy from Automotive Interior
of Ergo al no rn m u ic o s J Hussein et al., J Ergonomics 2017, 7:4 Journal of Ergonomics DOI: 10.4172/2165-7556.1000207 ISSN: 2165-7556 Research Article Open Access Investigation of Drivers FOV and Related Ergonomics Using Laser Shadowgraphy from Automotive Interior Wessam Hussein1*, Mohamed Nazeeh1 and Mahmoud MA Sayed2 1Military Technical College, KobryElkobbah, Cairo, Egypt 2Canadian International College, New Cairo, Cairo, Egypt *Corresponding author: Wessam Hussein, Military Technical College, KobryElkobbah, 11766, Cairo, Egypt, Tel: + 20222621908; E-mail: [email protected] Received date: June 07, 2017; Accepted date: June 26, 2017; Publish date: June 30, 2017 Copyright: © 2017 Hussein W, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract A new application of laser shadowgraphy in automotive design and driver’s ergonomics investigation is described. The technique is based on generating a characterizing plot for the vehicle’s Field of View (FOV). This plot is obtained by projecting a high divergence laser beam from the driver’s eyes cyclopean point, on a cylindrical screen installed around the tested vehicle. The resultant shadow-gram is photographed on several shots by a narrow field camera to form a complete panoramic seen for the screen. The panorama is then printed as a plane sheet FOV plot. The obtained plot is used to measure and to analyse the areal visual field, the eye and nick movement ranges in correlation with FOV, the horizontal visual blind zones, the visual maximum vertical angle and other related ergonomic parameters.