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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

Roman candle with 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

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

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

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.

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 device’s 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:

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

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

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.

Bokeh

In photography, bokeh (Originally/ˈboʊkɛ/, /ˈboʊkeɪ/ BOH-kay — also sometimes

pronounced as /ˈboʊkə/ BOH-kə, 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 depth of field is the region where the size of the circle of confusion is less than the resolution of the human eye.

An extremely shallow depth of field, a common effect in macrophotography, emphasizes bokeh.

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 85–150 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

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.

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

"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.

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. show the 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.

Long-exposure photography 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.

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

source—it can be small penlight—and 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.

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.


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