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Lesson # 3

Types of Lens , Mega Pixel , Image Quality .

Subject:

Photography

Faculty Name:

Partha Pratim

Samanta

Deviprasad Goenka Management College of Media Studies (dgmcms.org.in)

FY BA

India’s premier Media -school

+Lens

A camera lens is an optical lens used in conjunction with a camera

body and mechanism to make images of objects either on photographic

film or on other media capable of storing an image chemically or

electronically.

+How Lens Work

A lens gathers the rays of light coming from a scene and projects

them as reversed images onto the film at the back of the camera. You

can see this demonstrated below:

+ Types of Lens

Normal Lens

Tele Photo Lens

Wide Angle lens

+Types of Lens

The telephoto on the other hand allows the

photographer to capture light from greater

distances and make it appear to be closer than

the scene really is.

Finally the wide-angle does the opposite of the

telephoto lens, it make the scene seem farther

away and expands the viewable area.

+Types of Lens

When a photographer speaks of the speed of his or her lens, they

are simply referring to the measure of light that transmits through

the lens to the film.

A larger aperture lens allows more light than a small aperture

lens. This diameter is measured as an f-stop.

+Types of Lens

EF-S zoom- EF- S 10-18mm, EF- S 10-22 mm, EF- S 15-85mm, EF- S 17-

55mm, EF- S 17-85mm, EF- S 18-55mm, EF- S 18-135mm, EF- S 18-200mm,

EF- S 55-250mm

Ultra Wide Zoom EF-S 10–18mm, EF 16–35mm, EF-S 10–22mm,

EF 17–40mm, EF-S 15–85mm.

Standard Zoom- EF-S 17–55mm, EF 24–70mm, EF-S 17–85mm,

EF 24–105mm, EF-S 18–55mm, EF 28–135mm, EF-S 18–135mm,

EF 28–300mm, EF-S 18–200mm.

Telephoto- EF-S 55–250mm, EF 70–200mm.

Standard Prime EF 70–300mm EF 40mm, EF 100–400mm,

EF 50mm, EF 200–400mm.

+Types of Lens

Telephoto Prime Wide Angle Prime EF 85mm, EF 14mm,

EF 100mm, EF 20mm, EF 135mm, EF 24mm, EF 200mm, EF

28mm.

Super telephoto Prime EF 35mm, EF 300mm.

Macro EF 400mm , EF 50mm.

+Zoom Lenses & Prime Lenses

A zoom lens is one where the photographer can vary the focal

length within a pre-defined range, whereas this cannot be

changed with a "prime" or fixed focal length lens. The primary

advantage of a zoom lens is that it is easier to achieve a variety

of compositions or perspectives (since lens changes are not

necessary). This advantage is often critical for dynamic subject

matter, such as in photojournalism and children's photography.

An inexpensive prime lens can generally provide as good (or

better) image quality as a high-end zoom lens.

+Pixels & Megapixel

Digital cameras capture images as pixel

elements, known as pixels.

Note :- Simply put, a megapixel is equal to one

million pixels.

EXAMPLE :- 1 dot = 1 pixel

8 dot = byte Pixel

1024 dots = Kilo Pixel

AND

1048576 dots = Mega Pixel

And so on.

+Elements of picture quality

The number of megapixels is only one aspect relating to the quality of a

camera

or

Factors such as camera sensor and processor, and the optical quality

of a lens, play equally important roles.

Other elements determine the quality of photos and prints. They

include:

Good lighting of a subject

Proper focus and exposure

Image clarity (lack of blur due to camera shake or incorrect shutter

speed)

Shooting at the highest resolution and quality camera settings

+F-Length

The aperture range of a lens refers to the amount that the lens can

open up or close down to let in more or less light,

respectively. Apertures are listed in terms of f-numbers, which

quantitatively describe relative light-gathering area (depicted below).

Note: Above comparison is qualitative; aperture opening (iris) is rarely a

perfect circle, due to the presence of 5-8 blade-like lens diaphragms.

That larger aperture openings are defined to have lower f-numbers

(often very confusing).

+Depth of Field

The depth of field (DOF) is the portion of a scene that appears

sharp in the image. Although a lens can precisely focus at only one

distance, the decrease in sharpness is gradual on either side of the

focused distance, so that within the DOF, the unsharpness is

imperceptible under normal viewing conditions.

+Depth of Field

+Take Away Tips

Many cameras use interchangeable lenses.

When a photographer speaks of the speed of his or her lens, they are simply

referring to the measure of light that transmits through the lens to the film.

Think

Experiment

Move

Wait

Rule of Thirds