Introduction to Photography PDF

Introduction to photography L4 The lens aperture is a value that expresses the diameter of the diaphragm opening in relation to the lens focal length. It is usually referred to as f-number and is defined as the ratio of the focal length to the diameter of the diaphragm, "The aperture value is define...

Introduction to photography L4 The lens aperture is a value that expresses the diameter of the diaphragm opening in relation to the lens focal length. It is usually referred to as f-number and is defined as the ratio of the focal length to the diameter of the diaphragm, "The aperture value is defined as the ratio of the focal length to the aperture diameter. For example, f/2.8 corresponds to an aperture with a diameter of 1/2.8 focal lengths. Lenses capable of providing a large aperture diameter are often called fast lenses, "The aperture stop of a photographic lens can be adjusted to control the amount of light reaching the film or Image sensor' "The aperture stop of a photographic lens can be adjusted to control the amount of light reaching the film or image sensor" "The diaphragm functions much like the iris of the eye, it controls the effective diameter of the lens opening. Its movable leaves can be opened wide to let in more light or closed down to let in less light" "The size of an aperture is indicated by its f-number or f-stop. There is a standardized full-stop series of numbers on the f-stop scale ,1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22 32, 45" The lower the F/stop number, the wider the diaphragm opening on the lens. The higher the F/Stop number, the smaller the diaphragm opening in the lens. A lens that is set at f/4 admits half as light as one set at f/2.8 and only a quarter as much as one set at f/2 I - In the camera viewfinder 2- In the data-panel readout 3- On the lens barrel 4- On the LCD panel "Depth of field (DOF) is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image" That plane of sharpest focus, measured from the camera's image plane called the "Focal Distance" "A large depth of field renders virtually all of the scene in sharp detail" "A shallow depth of field has a limited range of distance in focus. Items nearer or more distant than the point of primary focus will become progressively more blurred" "A large depth of field allows the audience to view the details of the image as they choose" "A shallow depth of field can be used to force the audience to concentrate on what the photographer wants them to notice" Distance to The Subject "As the camera is moved closer the depth of field becomes smaller and as the camera is moved away it becomes larger Lens Aperture "The bigger the lens opening, The shallower the depth of field So The smaller the lens opening, The deeper the depth of field" Focal Length 35mm "As the lens focal length is increased the depth of field decreases Focal Length 35mm "As the lens focal length is increased the depth of field decreases L5 Aperture* Aperture is a device that allows light to enter for a specific time to expose photographic film or electronic light sensor to capture a permanent image of the scene. Its units are fractions of a second. *Types of Apertures* 1. Simple leaf aperture: Consists of mechanisms with moving metal leaves. 2. Diaphragm aperture: Same principle as simple leaf aperture. 3. Focal plane aperture: Located in front of the sensor and moves an aperture across the film until the entire frame is exposed. 4. Electronic aperture: Digital image sensors can be built to function similarly to a camera aperture by moving multiple pixel charges simultaneously. *Global aperture* 1. The image is integrated without interruption in time. 2. Superior image quality with reduced blur movement. 3. More accurate measurements. 4. No moving mechanical parts. 5. No flash is required to stop blur movement. *Aperture speed* 1. Determines the amount of light that reaches the film. 2. Determines the amount of movement in the image. 3. Controls "clear motion", where a faster aperture speed results in a clearer focus on the subject. *Common aperture speeds* 1, 2, 4, 8, 16, 32, 60, 125, 250, 500, 1000. *Exposure* Exposure = Time × Intensity 1. Exposure can be adjusted by aperture speed and lens aperture. 2. There are two types of light meter: incident light meter and reflected light meter. *Exposure types* 1. Full auto exposure. 2. Program mode. 3. Aperture priority mode. 4. Aperture speed priority mode. 5. Manual mode. *Shooting situations* 1. Sports. 2. Portrait. 3. Night portrait. 4. Landscape. 5. Macro. L6 Photographic Film "Photographic film is a sheet of plastic (polyester, nitrocellulose or cellulose acetate) coated with an emulsion containing light-sensitive silver halide salts bonded by gelatin. When the emulsion is sufficiently exposed to light, it forms a latent (invisible) image. Chemical processes can then be applied to the film to create a visible image, in a process called film developing" Photographic Film "In black-and-white photographic film there is usually one layer of silver salts. When the exposed grains are developed, the silver salts are converted to metallic silver, Image Sensor "An image sensor is a device that converts an optical image into an electronic signal. The most currently used are charge-coupled device (CCD) or complementary metal oxide semiconductor Image Sensor "It consists of a collection of tiny light-sensitive diodes. Diodes convert photons (light) into electrons (electrical charge). These diodes are called photosites. sensitive diodes = photo sites = photo elements = pixels Capturing Color Trilinear Image Sensor Spinning Disk Beam Splitter Bayer Filter Pattern Three Layers of Pixels Sensor Capturing Color Trilinear Image Sensor Capturing Color Trilinear Image Sensor A trilinear image sensor captures color information by using three linear arrays of photosites, each sensitive to one of the primary colors (red, green, and blue). As the image moves across the sensor, each line captures its respective color component. Capturing Color Spinning Disk Capturing Color Beam Splitter A beam splitter in digital cameras divides incoming light into separate color components by using prisms or dichroic mirrors. Each color component is directed to a different sensor or sensor area, allowing for precise capture of red, green, and blue light. Capturing Color Three Layers of Pixels Sensor Capture color information by stacking three layers of photosites, each sensitive to a different primary color (red, green, and blue). Capturing Color  Bayer Filter Pattern Using the Bayer filter pattern to break up the sensor into a variety of red, blue, and green pixels, This process of looking at the other pixels in the neighborhood in a sensor and making an educated guess is called interpolation" Resolution "Resolution is the number of pixels captured by the photosites of the image sensor. Resolution I Megapixel Camera image sensor would = I million pixels differ in size depending on the size of the image sensor' Image Sensor Image resolution in both images is the same although they are produced from different sizes "Memory cards are used to store information from cameras and other devices. Storage capacity:Choose a card with enough space for the number of photos and videos you plan to capture. Speed: Faster cards allow for quicker burst shooting and faster data transfer. Compatibility: Ensure the card type is compatible with your camera." Secure Digital (SD) "The majority of cameras record images and movies to one or more varieties of SD memory cards. L7 composition is the way in which different elements of an artwork are combined or arranged according to the design principles. with various terms such as design, form, visual ordering, or formal structure, page layout. Composition aims to create a balanced and aesthetically pleasing image" Color can aid organization so develop a color strategy and stay consistent with those colors. It can give emphasis to create a hierarchy It impacts visual perception Space Space refers to the distances or areas around, between, and within components of an object. Negative space can have a great impact, it implies a continuation of the scene and adds a certain serenity to the work. Unity the presentation of an integrated image, is perhaps as close to a rule as art can approach. Unity means that a congruity or agreement exists among the elements in a design; they look as though they belong together, as though some visual connection beyond mere chance has caused them to come together. Another term for the same idea is harmony. If the various elements are not harmonious, if they appear separate or unrelated, your composition falls apart and lacks unity. Focal Point  The emphasized element initially can attract attention and encourage the viewer to look closer, because it will be the main subject in a piece. Proportion refers to relative size, which is the size measured against other known elements' sizes. Balance Some equal distribution of visual weight, It is a universal aim of composition. is basically related to movement, Here the concept refers to the movement of the viewer's eye, progressive rhythm Again, the rhythm involves repetition, but in progressive rhythm, it's a repetition of changing elements regularly. There is a feeling of a sequential pattern. Rule of thirds The rule of thirds is a guideline followed by some visual artists. The objective is to stop the subjects) and areas of interest (such as the horizon) from bisecting the image, by placing them near one of the lines that would divide the image into three equal columns and rows, ideally near the intersection of those lines. Rule of thirds Dividing the parts of an image according to this proportion helps to sense of balance and interest. wants to apply the illusion of movement, or which is supposed to create a contextual bubble in the viewer's mind. Simplification Clutter can also be reduced through the use of lighting, as the brighter areas of the image tend to draw the eye, as do lines, squares and color. Framing The world is full of objects which make perfect natural frames, such as trees, archways and holes. By placing these around the edge of the composition you help to isolate the main subject from the outside world.