1. 1. Fireworks photography Fireworks photography is the process of taking photographs of fireworks at night. It is a type of night photography, specifically using available light of the fireworks instead of artificial light. Without using the flash on the camera, the photographer often exposes the image for a period of time, known as long exposure. Brighter fireworks sometimes support shorter exposure times. Exposing the image for long periods of time, requires that the camera is held as steady as possible by the photographer, as slight movements will result in notable camera shake. The most common and effective equipment used to prevent camera shake for long image exposures are a good sturdy tripod along with a remote shutter release (avoiding to have to touch the camera when taking the shot). Another challenge the photographer faces with exposure timing is having to estimate how long to expose the image in relation to when the firework bursts. Opening the shutter just before the firework bursts and then closing it after its finished would provide the ideal timing for capturing that 'perfect moment'. This can be achieved by setting the camera to 'b' or 'bulb' whereby exposure times are under the direct control of the photographer through the shutter release button. Examples The following samples are ordered from longer to shorter exposure time. Photo of exploding artillery shell Photo of exploding artillery shell fireworks. fireworks. Backyard fireworks in 4 July fireworks in Denton,Texas, 60 second exposure Denton, Texas, 60 second exposure
2. 2. Roman candlewith report.4 July fireworks in Denton, Texas,60 second exposure 4 July fireworks inPortland, Oregon, 10 second exposure 4th of July Fireworks inSan Jose,California, 2 second exposure 4 July fireworks from San Jose, 1 second exposure Fireworks in Cameron Park, California, 1/40th second exposure The World Showcase Lagoon at Epcot in Walt Disney World during IllumiNations: Reflections of Earth (the nightly fireworks show), 1/100th second exposure
3. 3. Multiple exposure In photography and cinematography, a multiple exposure is the superimposition of two or more exposures to create a single image, and double exposure has a corresponding meaning in respect of two images. The exposure values may or may not be identical to each other. Ordinarily, cameras have a sensitivity to light that is a function of time. For example, a one- second exposure is an exposure in which the camera image is equally responsive to light over the exposure time of one second. The criterion for determining that something is a double exposure is that the sensitivity goes up and then back down. The simplest example of a multiple exposure is a double exposure without flash, i.e. two partial exposures are made and then combined into one complete exposure. Some single exposures, such as "flash and blur" use a combination of electronic flash and ambient exposure. This effect can be approximated by a Dirac delta measure (flash) and a constant finite rectangular window, in combination. For example, a sensitivity window comprising a Dirac comb combined with a rectangular pulse, is considered a multiple exposure, even though the sensitivity never goes to zero during the exposure. Analogue Composer Karlheinz Stockhausen, double exposure made using a film camera, 1980 Double exposure made using a film camera In photography and cinematography, multiple exposure is a technique in which the camera shutter is opened more than once to expose the film multiple times, usually to different images. The resulting image contains the subsequent image/s superimposed over the original. The technique is sometimes used as an artistic visual effect and can be used to
4. 4. create ghostly images or to add people and objects to a scene that were not originally there. It is frequently used in photographic hoaxes. It is considered easiest to have a manual winding camera for double exposures. On automatic winding cameras, as soon as a picture is taken the film is typically wound to the next frame. Some more advanced automatic winding cameras have the option for multiple exposures but it must be set before making each exposure. Manual winding cameras with a multiple exposure feature can be set to double-expose after making the first exposure. Since shooting multiple exposures will expose the same frame multiple times, negative exposure compensation must first be set to avoid overexposure. For example, to expose the frame twice with correct exposure, a 1 EV compensation have to be done, and 2 EV for exposing four times. This may not be necessary when photographing a lit subject in two (or more) different positions against a perfectly dark background, as the background area will be essentially unexposed. Medium to low light is ideal for double exposures. A tripod may not be necessary if combining different scenes in one shot. In some conditions, for example, recording the whole progress of a lunar eclipse in multiple exposures, a stable tripod is essential. More than two exposures can be combined, with care not to overexpose the film. Ian Hornak.Title: Hannah Tillich's Mirror: Rembrandt's Three Trees Transformed Into The Expulsion From Eden, acrylic on canvas, 60 x 120 inches, 1978. An example of multiple as applied to fine art. Digital Multiple exposure of one person using Adobe Photoshop Digital technology enables images to be superimposed over each other by using a software photo editor, such as Adobe Photoshop or GIMP. These enable the opacity of the images to be altered and for an image to be overlaid over another. They also can set the
5. 5. layers to multiply mode, which 'adds' the colors together rather than making the colors of either image pale and translucent. Many digital SLR cameras allow multiple exposures to be made on the same image within the camera without the need for any external software. And some bridge cameras can take successive multiple exposures (sometimes up to nine) in one frame and in one shot. It is the same with High Dynamic Range which takes multiple shots in one burst captures, then combines all the proper shots into one frame.[1] Long exposures With traditional film cameras, a long exposure is a single exposure, whereas with electronic cameras a long exposure can be obtained by integrating together many exposures. This averaging also permits there to be a time-windowing function, such as a Gaussian, that weights time periods near the center of the exposure time more strongly. Another possibility for synthesizing long exposure from multiple-exposure is to use an exponential decay in which the current frame has the strongest weight, and previous frames are faded out with a sliding exponential window. Scanning film with multiple exposure Multiple exposure technique can also be used when scanning transparencies like slides, film or negatives using a film scanner for increasing dynamic range. With multiple exposure the original gets scanned several times with different exposure intensities. An overexposed scan lights the shadow areas of the image and enables the scanner to capture more image information here. Afterwards the data can be calculated into a single HDR image with increased dynamic range. Among the scanning software solutions which implement multiple exposure are VueScan and SilverFast.
6. 6. Afocal photography Afocal photography, also called afocal imaging or afocal projection is a method of photography where the camera with its lens attached is mounted over the eyepiece of another image forming system such as an optical telescope or optical microscope, with the camera lens taking the place of the human eye. Overview Afocal photography works with any system that can produce a virtual image of parallel light, for example telescopes and microscopes. Afocal photographic setups work because the imaging devices eyepiece produces collimated light and with the camera's lens focused at infinity, creating an afocal system with no net convergence or divergence in the light path between the two devices. In this system the device is focused on the object and the camera is placed above the eyepiece as close as possible. The drawback is the system will have a high focal ratio, with a correspondingly dim image, and some vignetting. A high focal ratio also means the field of view will be narrow. Field of view can be calculated using: Focal field of view/angle of view: Approximate: Precise:
7. 7. Use with optical telescopes One method of afocal photography is to mount a camera with its lens attached behind the eyepiece an Keplerian optical telescope, the combination giving the photographer a long focus lens. Historically afocal photography with 35 mm SLR or large format film cameras was a very difficult method of photography. With film cameras the bulk and mechanical shake had to be taken into consideration, with some setups employing a separate tripod for the camera (adding the complexity of setting up the camera in relationship to the eyepiece). The general difficulties of focus and exposure with film cameras, along with the detailed mathematical calculations, combined with the time lag of waiting for the film to be developed, meant film afocal photography could be pretty hit and miss. Spotting scope with a digital camera mounted afocally using an adapter. Digital afocal photography The advent of digital single-lens reflex camera and, moreover, compact point and shoot digital cameras has made the afocal method far more popular since this type of camera is small enough to mount directly on to telescopes or other devices, is for the most part a solid state device with minimal moving parts, has auto focus, has auto exposure adjustment, has some capacity for time exposure, usually has a zoom mechanism to crop vignetting, and has a video screen on the back side of the camera so you can actually see the image hitting the image plane.[3] A whole new industry has sprung up selling couplers and other devices for mounting digital cameras a focally. Simply holding the camera up to the eyepiece and snapping a
8. 8. picture can obtain usable results. Most popular types of consumer digital cameras have non-removable lenses so afocal photography is also the only method available for these types of cameras. Afocal astrophotography Afocal photography is a form of astrophotography long practiced by astronomers. Afocal setups with film and digital cameras are not the preferred system for astrophotography since astrophotographers have many ways of coupling a camera to an astronomical telescope, the simplest being prime focus (using no camera lens and allowing the image to fall directly onto the film, or image plane of a digital single- lens reflex camera or purpose built astronomical CCD camera). Almost from their invention amateur astronomers were adapting compact digital still and video cameras for use in afocal astrophotography. But since most celestial objects require a long exposure, compact consumer digital cameras are somewhat problematic due to their high inherent sensor noise. This noise limits their usefulness, especially since point-objects, such as stars, can be obscured by even one "hot" pixel. The narrow field of view for this type of photography lends itself to lunar and planetary objects. Continuing advancements in digital camera and image manipulation have somewhat overcome this limitation and digital afocal astrophotography has become more popular. A "digiscoped" photo of agoosander, taken with a Fujifilm digital camera and a Kowa spotting scope Daytime afocal photography Since the development of compact digital cameras, afocal photography is also widely used by birdwatchers, naturalist, and other photographers. In the birdwatching community it quickly acquired the coined name of digiscoping. Birdwatchers and naturalist found a digital camera used afocally with a spotting scope to be a particularly effective technique since it gave them an easy way to record their subjects (sometimes by simply holding the camera up to the eyepiece) as well as allowing them to take relatively high quality photographs. Since these
9. 9. types of photographs are usually single subjects (narrow field) in daylight hours, the light loss and narrow angle of view are not a hindrance, and the high effective focal lengths are a plus. It also gives the photographer the use of a very long lens without buying and lugging around extra equipment (except maybe a small afocal adapter). This technique has lent itself to many other types of photography including photographing plants (for example, wild orchids growing in the canopy of a jungle), insects (for example, wild bees near their beehive), other shy or dangerous wild animals, or details in old buildings (for example, statues/gargoyles on the roof of old churches/castles). Afocal secondary lenses Besides combining a Keplerian telescope with a camera, there are also dedicatedsecondary lens afocal attachments that mount on the front of a camera lens to work in the role of a teleconverter, technically called teleside converters. These lenses are usually Galilean telescopes that alter the width of the entering beam of light without affecting the divergence of the beam, so they can change the effective focal length 1 to 3 times without increasing focal ratio. There are models that are 6x or 8x and even Russian made 12x to 14x Gregorian maksutov designs that can be used as long lenses and microscopes.[6] Like their Keplerian counterparts these can be universally adapted to most camera lenses with the proper type of adapter.
10. 10. Bokeh In photography, bokeh (Originally/bok/, /boke/ BOH-kay also sometimes pronounced as /bok/ BOH-k, Japanese: [boke]) is the aesthetic quality of the blur produced in the out-of-focus parts of an image produced by a lens. Bokeh has been defined as "the way the lens renders out-of-focus points of light". Differences in lens aberrations andaperture shape cause some lens designs to blur the image in a way that is pleasing to the eye, while others produce blurring that is unpleasant or distracting"good" and "bad" bokeh, respectively. Bokeh occurs for parts of the scene that lie outside the depth of field. Photographers sometimes deliberately use a shallow focus technique to create images with prominent out-of-focus regions. Bokeh is often most visible around small background highlights, such as specular reflections and light sources, which is why it is often associated with such areas. However, bokeh is not limited to highlights; blur occurs in all out-of-focus regions of the image. Coarse bokeh on a photo shot with an 85 mm lens and 70 mm entrance pupil diameter, which corresponds to f /1.2 Bokeh and lens design The depthof field is theregion wherethe size of thecircle of confusion isless than the resolution of the human eye. An extremely shallow depth of field, a common effect in macrophotography,emphasizesbokeh.
11. 11. 200 mm lens at f/2. An example of the bokeh produced by the Canon 85 mm prime f/1.8 lens. The polygonal shapes are due to the 8- bladed aperture diaphragm being slightly closed. At its full aperture (f/1.8) these shapes would be smooth and not polygonal. The bokeh produced by acatadioptric lens (also called a mirror lens). Catadioptric lens bokeh seen in more detail. Though difficult to quantify, some lenses have subjectively more pleasing out-of-focus areas. "Good" bokeh is especially important for macro lenses and long telephoto lenses, because they're typically used in situations that produce shallow depth of field. Good bokeh is also important for medium telephoto lenses (typically 85150 mm on 35 mm format). When used in portrait photography (for their "natural" perspective), the photographer usually wants a shallow depth of field, so that the subject stands out sharply against a blurred background. Bokeh characteristics may be quantified by examining the image's circle of confusion. In out- of-focus areas, each point of light becomes an image of the aperture, generally a more or less round disc. Depending how a lens is corrected for spherical aberration, the disc may be uniformly illuminated, brighter near the edge, or brighter near the center. Lenses that are poorly corrected for spherical aberration will show one kind of disc for out-of-focus points in front of the plane of focus, and a different kind for points behind. This may actually be
12. 12. desirable, as blur circles that are dimmer near the edges produce less-defined shapes which blend smoothly with the surrounding image. An example of the creative application of bokeh. The shape of the aperture has an influence on the subjective quality of bokeh as well. For conventional lens designs (with bladed apertures), when a lens is stopped down smaller than its maximum aperture size (minimum f-number), out-of-focus points are blurred into the polygonal shape formed by the aperture blades. This is most apparent when a lens produces hard-edged bokeh. For this reason, some lenses have many aperture blades and/or blades with curved edges to make the aperture more closely approximate a circle rather than a polygon. Minolta has been on the forefront of promoting and introducing lenses with near-ideal circular apertures since 1987, but most other manufacturers now offer lenses with shape-optimized diaphragms, at least for the domain of portraiture photography. In contrast, a catadioptric telephoto lens renders bokehs resembling doughnuts, because its secondary mirror blocks the central part of the aperture opening. Recently, photographers have exploited the shape of the bokeh by creating a simple mask out of card with shapes such as hearts or stars, that the photographer wishes the bokeh to be, and placing it over the lens.[11] Leica lenses, especially vintage ones, are often claimed to excel in bokeh quality because they used to have 11, 12, or 15 blades. Because of this, the lenses don't need to reach wide apertures to get better circles (instead of polygons). In the past, wide aperture lenses (f/2, f/2.8) were very expensive, due to their complex mathematical design and manufacturing know-how required, at a time when all computations and glass making were done by hand. Leica could reach a good bokeh at f/4.5. Today it is much easier to make an f/1.8 lens, and a 9-bladed lens at f/1.8 is enough for an 85mm lens to achieve great bokeh.
13. 13. Some lens manufacturers including Nikon, Minolta, and Sony make lenses designed with specific controls to change the rendering of the out-of-focus areas. The Nikon 105 mm DC-Nikkor and 135 mm DC-Nikkor lenses (DC stands for "Defocus Control") have a control ring that permits the over-correction or under-correction of spherical aberration to change the bokeh in front of and behind thefocal plane. The Minolta/Sony STF 135mm f/2.8 [T4.5] (with STF standing for smooth trans focus) is a lens specifically designed to produce pleasing bokeh. It is possible to choose between two diaphragms: one with 9 and another with 10 blades. Anapodization filter is used to soften the aperture edges which results in a smooth defocused area with gradually fading circles. Those qualities made it the only lens of this kind on the market from its introduction in 1999 to 2014. In 2014 Fuji film announced a lens utilizing a similar apodization filter in the Fujinon XF 56mm F1.2 R APD lens. The 'Sigma YS System Focusing' 135mm f/2.8 also has an extra manually-moved component, intended to compensate for aberration at close-focus distances. It can be re- purposed for defocus control. The use of anamorphic lenses will cause bokeh to appear differently along the horizontal and vertical axes of the lens, becoming cylindrical compared to those in a spherical lens. Emulation No bokeh or blur Synthetic bokeh Gaussian blur Bokeh can be simulated by convolving the image with a kernel that corresponds to the image of an out-of-focus point source taken with a real camera. Unlike conventional convolution, this convolution has a kernel that depends on the distance of each image point and at least in principle has to include image points that are occluded by objects in the foreground. Also, bokeh is not just any blur. To a first approximation, defocus blur is convolution by a uniform disk, a more computationally intensive operation than the
14. 14. "standard" Gaussian blur; the former produces sharp circles around highlights whereas the latter is a much softer effect.Diffraction may alter the effective shape of the blur. Some graphics editors have a filter to do this, usually called "Lens Blur." This is an illustration of work done to explain the different types of Bokeh photography An alternative mechanical mechanism has been proposed for generating bokeh in small aperture cameras such as compacts or cellphone cameras, called image destabilisation, in which both the lens and sensor are moved in order to maintain focus at one focal plane, while defocusing nearby ones. This effect currently generates blur in only one axis. Some advanced digital cameras have bokeh features which take several images with different apertures and focuses and then manually compose them afterward to one image. More advanced systems of bokeh use a hardware system of 2 sensors, one sensor to take photo as usual while other ones record depth information. Bokeh effect and refocusing can then be applied to an image after the photo is taken. As 'good' bokeh requires large diameter lenses with large apertures that cannot be used in smartphones and tablets, the Android 4.4 KitKat featured an algorithm in its camera app to simulate bokeh. Other applications In 2009, a research group at MIT Media Lab showed that the bokeh effect can be used to make imperceptibly small barcodes, or bokodes. By using barcodes as small as 3 mm with a small lens over them, if the barcode is viewed out of focus through an ordinary camera focused at infinity, the resulting image is large enough to scan the information in the barcode.
15. 15. Contre-jour Contre-jour photo taken directly against the Contre-jour emphasizes the outline of the man setting sun causing loss of subject detail and and the tunnel entrance. The ground reflections colour, and emphasis of shapes and lines. showthe position of the man. Medium: Digital Medium: Colour digital image. scan from B&W paper print. Contre-jour (French for "against daylight") is a photographic technique in which the camera is pointing directly toward a source of light. Contre-jour produces backlighting of the subject. This effect usually hides details, causes a stronger contrast between light and dark, creates silhouettes and emphasizes lines and shapes. The sun, or other light source, is often seen as either a bright spot or as a strong glare behind the subject. Fill light may be used to illuminate the side of the subject facing toward the camera. Silhouetting occurs when there is a lighting ratio of 16:1 or more; at lower ratios such as 8:1 the result is instead called low-key lighting.
16. 16. Long-exposurephotography Long-exposure photography or time-exposure photography involves using a long- duration shutter speed to sharply capture the stationary elements of images while blurring, smearing, or obscuring the moving elements. Long-exposure photography captures one element that conventional photography does not: time. The paths of bright moving objects become clearly visible. Clouds form broad bands, head and tail lights of cars become bright streaks, stars form trails in the sky and water smooths over. Only bright objects will form visible trails, however, dark objects usually disappear. Boats during daytime long exposures will disappear, but will form bright trails from their lights at night. Technique Whereas there is no fixed definition of what constitutes "long", the intent is to create a photo that somehow shows the effect of passing time, be it smoother waters or light trails. A 30-minute photo of a static object and surrounding cannot be distinguished from a short exposure, hence, the inclusion of motion is the main factor to add intrigue to long exposure photos. Images with exposure times of several minutes also tend to make moving people or dark objects disappear (because they are in any one spot for only a fraction of the exposure time), often adding a serene and otherworldly appearance to long exposure photos.
17. 17. A long exposure photo of a watch in the dark. Note the appearance of the second hand as it rotates, showing that this was a 30-second exposure. The hour hand (which has only moved barely) is clear, while the minute hand is slightly blurry from a half a minute of movement. When a scene includes both stationary and moving subjects (for example, a fixed street and moving cars or a camera within a car showing a fixed dashboard and moving scenery), a slow shutter speed can cause interesting effects, such as light trails. Long exposures are easiest to accomplish in low-light conditions, but can be done in brighter light using neutral density filters or specially designed cameras. Night photography Long-exposure photography is often used in a night-time setting, where the lack of light forces longer exposures, if maximum quality is to be retained. Increasing ISO sensitivity allows for shorter exposures, but substantially decreases image quality through reduced dynamic range and higher noise. By leaving the camera's shutter open for an extended period of time, more light is absorbed, creating an exposure that captures the entire dynamic range of the digital camera sensor or film. If the camera is stationary for the entire period of time that the shutter is open, a very vibrant and clear photograph can be produced. Light painting In this technique, a scene is kept very dark and the photographer or an assistant takes a light sourceit can be small penlightand moves it about in patterns. The light source can be turned off between strokes. Often, stationary objects in the scene are illuminated by briefly turning on studio lights, by one or more flashes from a strobe light, or by increasing the aperture.
18. 18. Water and long exposure . Long exposures can blur moving water so it has mist-like qualities while keeping stationary objects like land and structures sharp.