The Art of Photography A guide to digital Photography AN E-BOOK BY SHUTTER | TUTORIALS www.shuttertutorials.wordpress.com | www.facebook.com/ShutterTutorials Author Tanay Shandilya CONTENT WORKING OF A DSLR CAMERA THE SENSOR AND CUP UNDERSTANDING LIGHT DYNAMIC RANGE UNDERSTANDING ISO EXPOSURE CAMERA SHUTTER SPEED UNDERSTANDING CAMERA LENSES UNDERSTANDING PHOTOGRAPHY ‘CIRCLE OF CONFUSION’ OPTICAL ZOOMING PERSPECTIVE CHANGE THE HISTOGRAM FULL FRAME v/s CROPPED SENSOR GET TO KNOW FLASH PHOTOGRAPHY Working Of A DSLR Camera A camera based on the single-lens reflex (SLR) principle uses a mirror to show in a viewfinder the image that will be captured. The cross-section (side-view) of the optical components of an SLR shows how the light passes through the lens assembly (1), is reflected into the pentaprism by the reflex mirror (which must be at an exact 45 degree angle) (2) and is projected on the matte focusing screen (3) opens, and the image is projected and captured on the sensor (4), after which actions, the shutter closes, the mirror returns to the 45 degree angle, the diaphragm reopens, and the built in drive mechanism re-tensions the shutter for the next exposure. (5). Via a condensing lens (6) and internal reflections in the roof penta-prism. (7) the image is projected through the eyepiece (8) to the photographer‘s eye. Focusing is either automatic, activated by pressing half-way on the shutter release or a dedicated AF button, as is mainly the case with an autofocusing film SLR; or manual, where the photographer manually focuses the lens by turning a lens ring on the lens barrel. When an image is photographed, the mirror swings upwards in the direction of the arrow, the focal-plane shutter. There is often a ring of soft material around the focusing screen, which helps to both cushion the impact of the mirror slapping up and helps seal the mirror box from light entering through the eye piece. Some high end cameras incorporate a shutter into the eyepiece to further eliminate light that may enter there during long exposures. Phase-detection autofocus. The diagram shown here is an over-simplification in that it omits the sensors used to activate the drive for the autofocus system. Those sensors reside at the bottom of the mirror box. In such a system, the main mirror is slightly translucent in the center, which allows light to pass through it to a secondary mirror which reflects light to the sensors below. DSLRs typically use a phase detection autofocus system. This method of focus is very fast, and results in less focus ―searching‖, but requires the incorporation of a special sensor into the optical path, so it is usually only used in SLR designs. Digicams that use the main sensor to create a live preview on the LCD or electronic viewfinder must use contrast-detect autofocus instead, which is slower in some implementations. DSLR optical viewfinder vs. digital point-and-shoot camera LCD Depending on the viewing position of the reflex mirror (down or up), the light from the scene can only reach either the viewfinder or the sensor. Therefore, many older DSLRs do not provide ―live preview‖ (allowing focusing, framing, and depth-of-field preview using the display), a facility that is always available on digicams although today most DSLRs offer live view. The advantages of an optical viewfinder are that it alleviates eye-strain sometimes caused by electronic view finders (EVF), and that it constantly shows (except during the time for the sensor to be exposed) the exact image that will be exposed because its light is routed directly from the lens itself. Compared to ordinary digital cameras with their LCDs and/or electronic viewfinders the advantage is that there is no time lag in the image; it is always correct as it is being ―updated‖ at the speed of light. This is important for action and/or sports photography, or any other situation where the subject or the camera is moving too quickly. Furthermore, the ―resolution‖ of the viewed image is much better than that provided by an LCD or an electronic viewfinder, which can be important if manual focusing is desired for precise focusing, as would be the case in macro photography and ―micro-photography‖ (with a microscope). Compared to some low cost cameras that provide an optical viewfinder that uses a small auxiliary lens, the DSLR design has the advantage of being parallax-free; that is, it never provides an off-axis view. A disadvantage of the DSLR optical viewfinder system is that while it is used it prevents the possibility of using the LCD for viewing and composing the picture before taking it. Some people prefer to compose pictures on the display – for them this has become the de- facto way to use a camera. Electronic viewfinders may also provide a brighter display in low light situations, as the picture can be electronically amplified; conversely, LCDs can be difficult to see in very bright sunlight. The Sensor and CPU The sensor is the part of your camera that captures the light exposure filtered through the lens. For our intents and purposes, we‘re just going to call this the image. The way the sensor was produced, and how large or small it is, has a pretty big effect on the end result: your photograph. First of all, the size of the sensors matters. Compact point-and-shoot cameras have very small sensors and the difference in size between them is a smaller factor when choosing a camera. When it comes to cameras with interchangeable lenses, which include DSLRs and MILC/CSC/EVIL cameras (which are basically compact, mirrorless DSLR- like cameras that often—but not always—have smaller sensors), sensor size has a greater impact. Generally larger sensors provide better low- light performance, greater control over depth of field, and produce higher resolution images with less noise than a smaller sensor. The majority of DSLRs have a sensor size most commonly known as APS-C. An APS-C sensor is about half the size of a frame of 35mm film and generally magnifies all lenses by a factor of 1.6x. This means that using a 35mm lens on a DSLR with an APS-C sensor is basically the same as using a 56mm lens on a regular 35mm camera. This is good news for telephoto lenses but bad news for wide angle, as every lens isn‘t as wide as advertised when placed on an APS-C-based camera. A 10mm fish eye lens will produce photos like a 16mm wide-angle lens. It‘s not a major downside for most people, but it‘s important to know. Some higher-end DSLRs contain full-frame sensors, such as the popular Canon 5D Mark II, which is equivalent to the size of a frame of 35mm film. Full-frame sensor DSLRs have the previously mentioned benefits that come with large sensors, but also are not subject to the 1.6x magnification like you‘ll find with APS-C sensors. Basically, a full- frame sensor DSLR is about as close as you‘re going to get to 35mm film with a digital camera. While sensor design is very relevant to the image quality, and the only way you‘re going to be able to judge that quality for certain is to see or produce sample images, you should pay attention to the sensor‘s megapixel rating. In general, the more megapixels packed into a sensor the more noise you‘ll find in a given image. This is why you don‘t necessarily want to choose a camera with a high megapixel rating—especially when a camera has a smaller sensor. For most people, even a 6.3 megapixel camera is sufficient, but anywhere from 8-10 should be more than sufficient. The point is, don‘t just buy one camera over the other because it has a higher megapixel count. It may produce noisier, less-desirable results so you should always test first. Understanding Light The Three Properties of Light Today is one of those days that I wanted to take a step back to some basics again. This time I want to talk about the three primary properties of light, and since what we are doing as photographers is recording light, it is important to know how these properties play into getting a good image. While I had studied this before, attending a recent seminar from Ed Pierce made me realize that many reader may never have seen these concepts before. Quantity The first property of light that we want to look at is Quantity. This is the amount of light that is hitting the subject. You have several ways of adjusting the amount of light the camera will see. In some cases you can adjust the light output of your lights or use diffusers to cut down on the light if you have too much. You should all know that you can also adjust your aperture or shutter to adjust the amount of light coming into the camera. With DSLR‘s, don‘t forget you can also adjust your ISO setting. With four main ways to adjust for light quantity, this is one of the more versatile of the three properties. Quality The light quality is one of the more confusing properties and the one that gives new photographers the most trouble. Quality is not about the color of the light, it refers to whether the light is very harsh and will cause hard shadows, or is it softer with smoother shadows. The quality of the light will affect the overall contrast.