PHOTO GUIDE for USAID PARTNERS
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“Digital Single Lens Reflex”
PHOTOGRAPHY GENERIC ELECTIVE SEM-II DSLR stands for “Digital Single Lens Reflex”. In simple language, a DSLR is a digital camera that uses a mirror mechanism to either reflect light from a camera lens to an optical viewfinder (which is an eyepiece on the back of the camera that one looks through to see what they are taking a picture of) or let light fully pass onto the image sensor (which captures the image) by moving the mirror out of the way. Although single lens reflex cameras have been available in various shapes and forms since the 19th century with film as the recording medium, the first commercial digital SLR with an image sensor appeared in 1991. Compared to point-and-shoot and phone cameras, DSLR cameras typically use interchangeable lenses. Take a look at the following image of an SLR cross section (image courtesy of Wikipedia): When you look through a DSLR viewfinder / eyepiece on the back of the camera, whatever you see is passed through the lens attached to the camera, which means that you could be looking at exactly what you are going to capture. Light from the scene you are attempting to capture passes through the lens into a reflex mirror (#2) that sits at a 45 degree angle inside the camera chamber, which then forwards the light vertically to an optical element called a “pentaprism” (#7). The pentaprism then converts the vertical light to horizontal by redirecting the light through two separate mirrors, right into the viewfinder (#8). When you take a picture, the reflex mirror (#2) swings upwards, blocking the vertical pathway and letting the light directly through. -
Completing a Photography Exhibit Data Tag
Completing a Photography Exhibit Data Tag Current Data Tags are available at: https://unl.box.com/s/1ttnemphrd4szykl5t9xm1ofiezi86js Camera Make & Model: Indicate the brand and model of the camera, such as Google Pixel 2, Nikon Coolpix B500, or Canon EOS Rebel T7. Focus Type: • Fixed Focus means the photographer is not able to adjust the focal point. These cameras tend to have a large depth of field. This might include basic disposable cameras. • Auto Focus means the camera automatically adjusts the optics in the lens to bring the subject into focus. The camera typically selects what to focus on. However, the photographer may also be able to select the focal point using a touch screen for example, but the camera will automatically adjust the lens. This might include digital cameras and mobile device cameras, such as phones and tablets. • Manual Focus allows the photographer to manually adjust and control the lens’ focus by hand, usually by turning the focus ring. Camera Type: Indicate whether the camera is digital or film. (The following Questions are for Unit 2 and 3 exhibitors only.) Did you manually adjust the aperture, shutter speed, or ISO? Indicate whether you adjusted these settings to capture the photo. Note: Regardless of whether or not you adjusted these settings manually, you must still identify the images specific F Stop, Shutter Sped, ISO, and Focal Length settings. “Auto” is not an acceptable answer. Digital cameras automatically record this information for each photo captured. This information, referred to as Metadata, is attached to the image file and goes with it when the image is downloaded to a computer for example. -
Digital Camera Functions All Photography Is Based on the Same
Digital Camera Functions All photography is based on the same optical principle of viewing objects with our eyes. In both cases, light is reflected off of an object and passes through a lens, which focuses the light rays, onto the light sensitive retina, in the case of eyesight, or onto film or an image sensor the case of traditional or digital photography. The shutter is a curtain that is placed between the lens and the camera that briefly opens to let light hit the film in conventional photography or the image sensor in digital photography. The shutter speed refers to how long the curtain stays open to let light in. The higher the number, the shorter the time, and consequently, the less light gets in. So, a shutter speed of 1/60th of a second lets in half the amount of light than a speed of 1/30th of a second. For most normal pictures, shutter speeds range from 1/30th of a second to 1/100th of a second. A faster shutter speed, such as 1/500th of a second or 1/1000th of a second, would be used to take a picture of a fast moving object such as a race car; while a slow shutter speed would be used to take pictures in low-light situations, such as when taking pictures of the moon at night. Remember that the longer the shutter stays open, the more chance the image will be blurred because a person cannot usually hold a camera still for very long. A tripod or other support mechanism should almost always be used to stabilize the camera when slow shutter speeds are used. -
Fourth International Visual Field Symposium Bristol, April 13-16,198O
Documenta Ophthalmologica Proceedings Series volume 26 Editor H. E. Henkes Dr W. Junk bv Publishers The Hague-Boston-London 1981 Fourth International Visual Field Symposium Bristol, April 13-16,198O Edited by E. L. Greve and G. Verriest Dr W. Junk bv Publishers The Hague - Boston -London 1981 Distributors for the United States and Canada Kluwer Boston, Inc. 190 Old Derby Street Hingham, MA 02043 USA for all other countries Kluwer Academic Publishers Group Distribution Center P.O. Box 322 3300 AH Dordrecht The Netherlands ISBN 90 6193 165 7 (this volume) 90 6193 882 1 (series) Cover design: Max Velthuijs Copyright 0 1981 Dr W Junk bv Publishers, The Hague. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publishers. Dr W. Junk bv Publishers, P.O. Box 13713, 2501 ES The Hague, The Netherlands PRINTED IN THE NETHERLANDS INTRODUCTION The 4th International Visual Field Symposium of the International Perimetric Society, was held on the 13-16 April 1980 in Bristol, England, at the occasion of the 6th Congress of the European Society of Ophthalmology. The main themes of the symposium were comparison of classical perimetry with visual evoked response, comparison of classical perimetry with special psychophysi- cal methods, and optic nerve pathology. Understandably many papers dealt with computer assisted perimetry. This rapidly developing subgroup of peri- metry may radically change the future of our method of examination. New instruments were introduced, new and exciting software was proposed and the results of comparative investigations reported. -
Depth of Field Lenses Form Images of Objects a Predictable Distance Away from the Lens. the Distance from the Image to the Lens Is the Image Distance
Depth of Field Lenses form images of objects a predictable distance away from the lens. The distance from the image to the lens is the image distance. Image distance depends on the object distance (distance from object to the lens) and the focal length of the lens. Figure 1 shows how the image distance depends on object distance for lenses with focal lengths of 35 mm and 200 mm. Figure 1: Dependence Of Image Distance Upon Object Distance Cameras use lenses to focus the images of object upon the film or exposure medium. Objects within a photographic Figure 2 scene are usually a varying distance from the lens. Because a lens is capable of precisely focusing objects of a single distance, some objects will be precisely focused while others will be out of focus and even blurred. Skilled photographers strive to maximize the depth of field within their photographs. Depth of field refers to the distance between the nearest and the farthest objects within a photographic scene that are acceptably focused. Figure 2 is an example of a photograph with a shallow depth of field. One variable that affects depth of field is the f-number. The f-number is the ratio of the focal length to the diameter of the aperture. The aperture is the circular opening through which light travels before reaching the lens. Table 1 shows the dependence of the depth of field (DOF) upon the f-number of a digital camera. Table 1: Dependence of Depth of Field Upon f-Number and Camera Lens 35-mm Camera Lens 200-mm Camera Lens f-Number DN (m) DF (m) DOF (m) DN (m) DF (m) DOF (m) 2.8 4.11 6.39 2.29 4.97 5.03 0.06 4.0 3.82 7.23 3.39 4.95 5.05 0.10 5.6 3.48 8.86 5.38 4.94 5.07 0.13 8.0 3.09 13.02 9.93 4.91 5.09 0.18 22.0 1.82 Infinity Infinite 4.775 5.27 0.52 The DN value represents the nearest object distance that is acceptably focused. -
What's a Megapixel Lens and Why Would You Need One?
Theia Technologies white paper Page 1 of 3 What's a Megapixel Lens and Why Would You Need One? It's an exciting time in the security department. You've finally received approval to migrate from your installed analog cameras to new megapixel models and Also translated in Russian: expectations are high. As you get together with your integrator, you start selecting Что такое мегапиксельный the cameras you plan to install, looking forward to getting higher quality, higher объектив и для чего он resolution images and, in many cases, covering the same amount of ground with нужен one camera that, otherwise, would have taken several analog models. You're covering the basics of those megapixel cameras, including the housing and mounting hardware. What about the lens? You've just opened up Pandora's Box. A Lens Is Not a Lens Is Not a Lens The lens needed for an IP/megapixel camera is much different than the lens needed for a traditional analog camera. These higher resolution cameras demand higher quality lenses. For instance, in a megapixel camera, the focal plane spot size of the lens must be comparable or smaller than the pixel size on the sensor (Figures 1 and 2). To do this, more elements, and higher precision elements, are required for megapixel camera lenses which can make them more costly than their analog counterparts. Figure 1 Figure 2 Spot size of a megapixel lens is much smaller, required Spot size of a standard lens won't allow sharp focus on for good focus on megapixel sensors. a megapixel sensor. -
EVERYDAY MAGIC Bokeh
EVERYDAY MAGIC Bokeh “Our goal should be to perceive the extraordinary in the ordinary, and when we get good enough, to live vice versa, in the ordinary extraordinary.” ~ Eric Booth Welcome to Lesson Two of Everyday Magic. In this week’s lesson we are going to dig deep into those magical little orbs of light in a photograph known as bokeh. Pronounced BOH-Kə (or BOH-kay), the word “bokeh” is an English translation of the Japanese word boke, which means “blur” or “haze”. What is Bokeh? bokeh. And it is the camera lens and how it renders the out of focus light in Photographically speaking, bokeh is the background that gives bokeh its defined as the aesthetic quality of the more or less circular appearance. blur produced by the camera lens in the out-of-focus parts of an image. But what makes this unique visual experience seem magical is the fact that we are not able to ‘see’ bokeh with our superior human vision and excellent depth of field. Bokeh is totally a function ‘seeing’ through the lens. Playing with Focal Distance In addition to a shallow depth of field, the bokeh in an image is also determined by 1) the distance between the subject and the background and 2) the distance between the lens and the subject. Depending on how you Bokeh and Depth of Field compose your image, the bokeh can be smooth and ‘creamy’ in appearance or it The key to achieving beautiful bokeh in can be livelier and more energetic. your images is by shooting with a shallow depth of field (DOF) which is the amount of an image which is appears acceptably sharp. -
Using Depth Mapping to Realize Bokeh Effect with a Single Camera Android Device EE368 Project Report Authors (SCPD Students): Jie Gong, Ran Liu, Pradeep Vukkadala
Using Depth Mapping to realize Bokeh effect with a single camera Android device EE368 Project Report Authors (SCPD students): Jie Gong, Ran Liu, Pradeep Vukkadala Abstract- In this paper we seek to produce a bokeh Bokeh effect is usually achieved in high end SLR effect with a single image taken from an Android device cameras using portrait lenses that are relatively large in size by post processing. Depth mapping is the core of Bokeh and have a shallow depth of field. It is extremely difficult effect production. A depth map is an estimate of depth to achieve the same effect (physically) in smart phones at each pixel in the photo which can be used to identify which have miniaturized camera lenses and sensors. portions of the image that are far away and belong to However, the latest iPhone 7 has a portrait mode which can the background and therefore apply a digital blur to the produce Bokeh effect thanks to the dual cameras background. We present algorithms to determine the configuration. To compete with iPhone 7, Google recently defocus map from a single input image. We obtain a also announced that the latest Google Pixel Phone can take sparse defocus map by calculating the ratio of gradients photos with Bokeh effect, which would be achieved by from original image and reblured image. Then, full taking 2 photos at different depths to camera and defocus map is obtained by propagating values from combining then via software. There is a gap that neither of edges to entire image by using nearest neighbor method two biggest players can achieve Bokeh effect only using a and matting Laplacian. -
Shutter Speed in Digital Photography Stephen Sagers, Tooele County 4-H Agent Ron Patterson, Carbon County Ag/4-H Agent
March 2012 4H/Photography/2012-03pr Shutter Speed in Digital Photography Stephen Sagers, Tooele County 4-H Agent Ron Patterson, Carbon County Ag/4-H Agent Photography is the process of recording light. Film The Shutter cameras recorded the light on to the film while digital cameras record light on an image sensor. In The shutter is located behind the lens and mirrors order to prevent bright or dim light from creating an and opens when a photograph is taken. Most consumer cameras can shoot pictures with shutter overexposed or underexposed image the shutter th must open and close in the right amount of time. speeds from 1/2000 of a second to several seconds The amount of time it is opened depends on three (or indefinitely.) This feature is useful for freezing factors: the light intensity, the aperture setting, and motion or capturing effects like fireworks or the ISO or film speed. (Refer to separate factsheets running water. on ISO and aperture for a more detailed definition of these concepts.) In order to achieve proper exposure these three features must be balanced. The shutter speed is the easiest to adjust in order to obtain proper exposure. Exposure In digital photography exposure refers to the amount of light that reaches the image sensor. When too much light is recorded the picture will be washed out — overexposed. When too little light is recorded the image will be dark — underexposed. Figure 1. The inside of a film camera. The mirror Usually, neither situation is desirable. and shutter behind it move when it shoots a photograph. -
Aperture Efficiency and Wide Field-Of-View Optical Systems Mark R
Aperture Efficiency and Wide Field-of-View Optical Systems Mark R. Ackermann, Sandia National Laboratories Rex R. Kiziah, USAF Academy John T. McGraw and Peter C. Zimmer, J.T. McGraw & Associates Abstract Wide field-of-view optical systems are currently finding significant use for applications ranging from exoplanet search to space situational awareness. Systems ranging from small camera lenses to the 8.4-meter Large Synoptic Survey Telescope are designed to image large areas of the sky with increased search rate and scientific utility. An interesting issue with wide-field systems is the known compromises in aperture efficiency. They either use only a fraction of the available aperture or have optical elements with diameters larger than the optical aperture of the system. In either case, the complete aperture of the largest optical component is not fully utilized for any given field point within an image. System costs are driven by optical diameter (not aperture), focal length, optical complexity, and field-of-view. It is important to understand the optical design trade space and how cost, performance, and physical characteristics are influenced by various observing requirements. This paper examines the aperture efficiency of refracting and reflecting systems with one, two and three mirrors. Copyright © 2018 Advanced Maui Optical and Space Surveillance Technologies Conference (AMOS) – www.amostech.com Introduction Optical systems exhibit an apparent falloff of image intensity from the center to edge of the image field as seen in Figure 1. This phenomenon, known as vignetting, results when the entrance pupil is viewed from an off-axis point in either object or image space. -
12 Considerations for Thermal Infrared Camera Lens Selection Overview
12 CONSIDERATIONS FOR THERMAL INFRARED CAMERA LENS SELECTION OVERVIEW When developing a solution that requires a thermal imager, or infrared (IR) camera, engineers, procurement agents, and program managers must consider many factors. Application, waveband, minimum resolution, pixel size, protective housing, and ability to scale production are just a few. One element that will impact many of these decisions is the IR camera lens. USE THIS GUIDE AS A REFRESHER ON HOW TO GO ABOUT SELECTING THE OPTIMAL LENS FOR YOUR THERMAL IMAGING SOLUTION. 1 Waveband determines lens materials. 8 The transmission value of an IR camera lens is the level of energy that passes through the lens over the designed waveband. 2 The image size must have a diameter equal to, or larger than, the diagonal of the array. 9 Passive athermalization is most desirable for small systems where size and weight are a factor while active 3 The lens should be mounted to account for the back athermalization makes more sense for larger systems working distance and to create an image at the focal where a motor will weigh and cost less than adding the plane array location. optical elements for passive athermalization. 4 As the Effective Focal Length or EFL increases, the field 10 Proper mounting is critical to ensure that the lens is of view (FOV) narrows. in position for optimal performance. 5 The lower the f-number of a lens, the larger the optics 11 There are three primary phases of production— will be, which means more energy is transferred to engineering, manufacturing, and testing—that can the array. -
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.