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  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.[