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Camera & Lens Function Class Objectives 1.  Types of camera 2.  Shutter 3.  Aperture 4.  Standard or Normal lens; Telephoto lens, Wide angle lens; Zoom lens.

Camera How an image is formed

Optical Process

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Arabian scholar Ibn al Haitam, in the 10th century, described what can be called a camera obscura

Eye

Camera Types by Film size & Image Format

The Human Camera Medium Format Large Format

Small format

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Film size & Image Format

Camera Types by viewing system

Single Lens Reflex (SLR)

Range Finder

24 x 36mm

Twin Lens Reflex (TLR)

Basic Camera Types Camera types by Technology

Conventional Camera Depends on chemical, mechanical & optical process.

Panoramic Camera

Digital Camera It has sensors that converts light in to electrical charges which are then turned in to digital information.

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Under Water Camera

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Different Parts of a SLR Shutter Speed & Film speed Dial

Hot Shoe Film Rewind

Film Advance Lever

Shutter Release

Lens Lock Lens

Different Parts of a SLR

SLR- Single Lens Reflex

Professional Digital SLR

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Shutter Button

All modern SLRs share some basic features:

LCD Panel

• A body • A lens which is interchangeable. • An adjustable aperture which is inside the lens. • An adjustable shutter which is inside the body • A built in TTL light meter

Mode Dial Lens Release Button

Hot Shoe

Different Parts of a Digital SLR

Lens

Viewfinder

Menu Button

Play Button

Erase Button

LCD monitor

Quick Control Dial

Different Parts of a Digital SLR (Rear View)

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1550 Girolama Cardano recommends use of bi-convex lens in camera obscura to brighten image. Lens is a cylinder of shaped pieces of glass (or plastic) that bend rays of light from the subject to create a sharp image on image plane (film/ sensor).

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Focusing Ring

Different Parts of a Lens Aperture Ring

Focusing Split- Image Focusing

Superimposed- Image Focusing

Focusing is the process of moving the lens forward and backward until it produces the sharpest possible image of your main subject, or of the most important part of the scene, on the film in your camera.

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Ground-Glass Focusing

Automatic Focusing

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Focal Length Focal length is the distance between the lens and its image (on the film) when the lens is focused at infinity. Focal length is expressed in millimeters, abbreviated mm. A lens s focal length determines two things1.  The first is how big your main subject will be in a photograph, a variable called magnification. 2.  The second is how much of a scene you can fit in a frame , a variable called angle of view.

7.5 mm

28 mm

50 mm

105 mm

135 mm

300 mm

1000 mm

500 mm

50mm - Normal (or Standard) Lens for 35mm Cameras When focused on a subject (s) normal Lens collects light rays from an angle of view about 50°- viewing things with about the same perspective as the human eye (when staring straight ahead with one eye closed).

Angle of View & Magnification

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The Normal Lens

A

24mm

B

43.26 mm

A 6 cm

135 Format

8.48cm 120 Format

B

C

36 mm

6 cm

C

What constitutes Normal depends on the film size.

When the Focal length of a lens Equals the diagonal measurement of the film the lens is considered normal. AC2 = AB2 + BC2 AC2 = (24) 2 + (36) 2 = 576 + 1296 = 1872 AC = 43.26 mm

AC2 = (6) 2 + (6) 2 = 36 + 36 = 72 AC =8.48 cm = 84.8 mm

A normal lens is the best choice when you want your lens to create an image in which the scene s size relationships seem most natural.

The Long Lens or The Telephoto Lens [Ex- 70mm, 85mm, 105mm, 300mm, 1000mm etc.]

Lenses with focal lengths much beyond 50mm (for 35mm cameras) are called both long lenses and telephoto lens.

Single- Focal- Length Lenses

Zoom Lens

(Fixed-Focal-Length Lenses or

(Variable Focal Lengths)

Prime Lens)

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A telephoto lens magnifies the subject. This means they make the subject bigger (on the film and in the viewfinder) than it appears in life, without your having to move closer to it physically.

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Nick Brandt

Telephoto lenses ( example- 105mm or 135 mm) are popular for both candid photography (spontaneous people pictures) and street photography, because they allow you to position yourself at a distance from the subject, so you can work more discreetly.

Telephoto lens is useful when you want to photograph something in the distance and you can t or don t want to get closer to the subject.

The Wide Angle Lens [Ex- 14mm, 20 mm, 24mm, 28mm, 35mm ]

A wide angle focal length does just what it sounds like it does: it takes in a larger section of the scene you are photographing than you would get with a normal focal length. A wide angle makes subject look smaller than they would be rendered by a normal focal length.

Steve McCurry Railway, Agra, 1983

Also the effect of using the lens is to compress the picture space, making near and far elements seem physically closer together.

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The most obvious time to use a wide angle lens is when you otherwise wouldn t be able to get far enough away from a subject to include it all.

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Tele Zoom (Ex- 100-300mm)

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Wide angle- Tele zoom (Ex- 24-135 mm)

Photo Saiful Huq

Wide angle lens are valuable for setting up relationships between foreground and background (near and far) elements. Landscape photographers are specially fond of this tactic, composing with prominent foreground elements (rocks, plants, structures & so on) and also showing a wide expanse of background (mountains, sky and so on).

A wide- angle focal length lets you get closer to the subject and it gives generous depth of field. So they are very popular among photojournalists.

Wide Angle Zoom (Ex- 12- 24 mm)

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Aperture

f-2.8

Smaller f/stop numbers are larger lens openings and permits more light to pass to the film.

f-4

Moving to the next f/stop number either halves or doubles the amount of light.

Depth Of Field The distance range within which objects appear in acceptably sharp focus is commonly called the depth of field.

f-5.6 f-8 f-11 f-16 f-22

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Larger f/stop numbers are smaller lens openings and reduce light passed to the film.

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Depth of Field The distance range within which objects appear in acceptably sharp focus is commonly called the depth of field. The wider the lens aperture, the shallower the depth of field.

Photo from  Wikipedia  

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Photo from  Wikipedia  

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Photo: Moinuddin  

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Shutter

Depth of Field & Aperture Size

Depth of Field & Changing lenses Shortest lens results in the greatest DOF

The shutter speed determines how long the film or sensor is exposed to light.

Depth of Field & Camera Distance Closer the subject narrower the DOF Barbara Morgan

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Shutter

Shutter Speed Moving the shutter speed dial to the next stop either halves or doubles exposure time.

B, 8,4, 2 ,1, 2,4,8,15,30,60,125,250,500,1000,2000...

B= Bulb 8= 8 seconds 1= 1 second 250= 1/250 second

Catching a Moment or Time Exposure [Shutter Priority]

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Controlling Motion With Shutter Speed 1/8

1/15

1/60

1/250

1/1000

1/30

1/30

1/125

1/125

1/500

The direction in which a moving subject is traveling affects how high a shutter speed you’ll need.

Photo from  Wikipedia    

Photo from  Wikipedia    

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Photo from  Wikipedia    

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Photo from Wikipedia

Photo from Wikipedia

Summary 1.  Types of camera- Small, medium & large format camera - View camera, TLR, Rangefinder & SLR. 2.  Moving the shutter speed dial or the f-number to the next stop either halves or doubles exposure. 3.  Use of Shutter: Exposure control, Catching a Moment or Time Exposure 4.  Use of Aperture: Exposure control, Depth of field & Brightness control 5.  Standard or Normal lens; Telephoto lens, Wide angle lens; Zoom lens.

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camera & lens fynction by Topu.pdf  

photography class

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