working of digital cameras

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Parts and working of a telescopic zoom camera

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Page 1: Working of digital cameras

Parts and working of a telescopic zoom camera

Page 2: Working of digital cameras

Basics of capturing a picture

Light enters a dark box through a small hole and creates an inverted image on the wall opposite the hole.

Page 3: Working of digital cameras

Role of a camera in capturing pictures A still camera is an optical device which creates a

single image of an object or scene, and records it on an electronic sensor or photographic film.

All cameras use the same basic design: light enters an enclosed box through a converging lens and an image is recorded on a light-sensitive medium.

A shutter mechanism controls the length of time that light can enter the camera.

Page 4: Working of digital cameras

A movie camera or a video camera operates similarly to a still camera, except it records a series of static images in rapid succession, commonly at a rate of 24 frames per second.

When the images are combined and displayed in order, the illusion of motion is achieved.

Page 5: Working of digital cameras

Camera buttons and controls1. Lens Alignment 2. Flash Pop Up Button 3. Lens Release 4. Depth of Field preview5. Lens contacts 6. Mirror 7. Grip8. Shutter Release Button 9. Focus Assist Beam 10.Pop Up Flash 

Page 6: Working of digital cameras

1. Viewfinder2. Diopter Adjustment 3. Rubber Eye-cup 4. Joystick Dial 5. Exposure Lock/Zoom Button 6. Focus Point Selector/Zoom Button 7. Write Indication Light 8. Jog Dial and Set button 9. On/Off Button 10.Erase Button 11,12,13,14- UI buttons12-LCD screen

Page 7: Working of digital cameras

1. Light for LCD Display 2. Auto focus/white balance3. Drive/ISO 4. Shutter Button 5. Top Dial 6. Metering/Flash Compensation7. LCD Screen 8. Hotshoe9. Exposure control Dial 10.Flash

Page 8: Working of digital cameras

Main functional parts Aperture ring-This part of the DSLR is used to manually

select the desired aperture.

Dust removal system-These systems work by shaking the sensor very rapidly in order remove the dust particles.

Focus ring-The focus ring is used to manually let you have a control over the focus.

Live view-. This is especially useful for photographers using a tripod or working at odd angles.

Mount-The mount is the physical connection between the lens and the camera body.

Page 9: Working of digital cameras

Prime lens-These lenses are the ones which are fixed within the camera, which offer the best image quality.

Sensor-Used to capture incoming light.

Zoom lens-Unlike prime lenses, a zoom lens can cover a range of focal lengths.

Viewfinder-A viewfinder will display the various focus areas superimposed over the image

Zoom ring-This is the ring that one adjusts to manually control the zoom of your subject.

Page 10: Working of digital cameras

Zoom lens

Page 11: Working of digital cameras

A zoom lens is a mechanical assembly of lens elements for which the focal length (and thus angle of view) can be varied, as opposed to a fixed focal length (FFL) lens or prime lens.

Zoom lenses are often described by the ratio of their longest to shortest focal lengths.

A zoom lens with focal lengths ranging from 100 mm to 400 mm may be described as a 4:1 or "4×" zoom.

This ranges up to 19× in SLR camera lenses, 83× in amateur digital cameras and can be as high as 300× in professional television cameras.

But photographic zoom lenses beyond 3× cannot generally produce imaging quality on par with prime lenses.

It features very complicated internal construction.

Page 13: Working of digital cameras

The three lenses of the afocal system areL1, L2, L3. 

Lens L3 is fixed, but lenses L1 and L2 can be moved axially in a particular non-linear relationship, changing the overall focal length of the system.

While the negative lens L2 moves from the front to the back of the lens, the lens L1 moves forward and then backward in a parabolic arc.

In doing so, the overall angular magnification of the system varies, changing the effective focal length of the complete zoom lens.

Page 14: Working of digital cameras

The two fundamental parameters of an optical lens are the focal length and the maximum aperture.

The lens' focal length determines the magnification of the image projected onto the image plane, and the aperture the light intensity of that image.

Focal lengths are usually specified in millimetres (mm).

28 mm lens  50 mm lens 

70 mm lens  210 mm lens 

Page 15: Working of digital cameras

With a large pinhole, the image spot is large, resulting in a blurry image. 

With a small pinhole, light is reduced and diffraction prevents the image spot from getting arbitrarily small. 

With a simple lens, much more light can be brought into sharp focus. 

Page 16: Working of digital cameras

Parts The mechanical movement of the

optics within this zoom lens can be broken down into three independently moving groups of optical elements and one stationary group of optical elements.

the focus group,the variator group,the compensator group, andthe master group.

Page 17: Working of digital cameras

Functions of various parts The focus group moves forward or backward as necessary for

focusing the lens.

The variator group of lens elements, like its name implies, varies the magnification power of the focus group.

The variator group alone isn't enough to achieve a true zoom function and maintain focus.

The compensator group of lens elements maintains proper focus when zooming a true zoom lens.

True zoom lenses have a compensator group which moves in the same direction but at a different rate compared to the focus group.

Page 18: Working of digital cameras

The compensator group is also partly responsible for changing the focal length of the lens when it is zoomed.

The variator and compensator groups work together to create the change in focal length when the lens is zoomed, and the compensator group also assures that the lens remains in focus while being zoomed.

The master group serves to relay the variable magnifications from the other groups to the camera's focal plane.

It is also optically constructed to correct aberrations from the other optical groups.

Page 19: Working of digital cameras

Zoom Lens Mechanics

Zoom lenses feature complicated to extremely complex internal construction.

The zoom's mechanics not only must move the various optical groups with the correct rates of movement, but also must do this precisely while also maintaining optical alignment of the optical elements.

Page 20: Working of digital cameras

The movement of the various optical groups is accomplished via a series of nested barrels or sleeves.

These sleeves feature machined cam-slots and cam-followers.

In zoom lenses, some sleeves remain stationary while others rotate or move back and forth.

Page 21: Working of digital cameras

Exploded view of a camera

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Cut section

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Page 26: Working of digital cameras

Detailed working of a camera

Page 27: Working of digital cameras

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