digital photographer

38
SEMINAR SEMINAR ON ON DIGITAL PHOTOGRAPHY DIGITAL PHOTOGRAPHY & & IMAGE SENSORS IMAGE SENSORS

Upload: sajan-sahu

Post on 06-Jul-2015

76 views

Category:

Small Business & Entrepreneurship


0 download

DESCRIPTION

Digital photography

TRANSCRIPT

Page 1: Digital photographer

SEMINAR SEMINAR ONON

DIGITAL PHOTOGRAPHYDIGITAL PHOTOGRAPHY&&

IMAGE SENSORSIMAGE SENSORS

Page 2: Digital photographer

GUIDED GUIDED BY BY

Dr. JIBITESH MISHRA SIRDr. JIBITESH MISHRA SIRPRESENTED PRESENTED

BYBY

RAPARTHI SIVA SANKARRAPARTHI SIVA SANKAR

1MCA/021MCA/02

Page 3: Digital photographer

CONTENTS• If you are in the market for a digital camera,

here's the guide you've been looking for. It takes you around and through the digital camera so you know how it works and what its  features are used for. It has hundreds of links to the best sources and products so you can learn even more. I Hope you enjoy it!

1. What is a Digital Photograph?2. Why go digital? 3. Image Sensors 4. Types of Digital Cameras5. Image Storage

Page 4: Digital photographer

6. Downloading Images7. Image Compression 8. Preview Screens & view finders

9. Lenses10. Batteries

11. Other Features 12. Is it Time to Buy? 13. The Rules of the Shopping Game14. Digital Photography Web Sites

Page 5: Digital photographer

INTRODUCTION• Digital photography begins with capturing

images in a digital format. You can do this by taking photographs with a film camera and then scanning the slides, negatives, or prints. However, it’s much faster and easier to capture images with a digital camera. At the moment there are many digital cameras and new ones seem to be introduced weekly. If you are at all like me, these amazing devices are tempting indeed.

Page 6: Digital photographer

• It’s clear that almost everyone wants to know more about what features to consider when buying a camera and how to use those features once they own one. Even if you’re an experienced photographer, digital cameras introduce new criteria that you have to consider in your buying decision.

The Canon S20

Page 7: Digital photographer

Straightforward answers to the questions you might have, including the following:

• Why go digital?• What is a digital photograph?• How does a digital camera work?• What is digital photography?• How good are digital cameras?• What features should I look for in a digital camera?• What resolution do I need?• Do I want a point-and-shoot camera or one with creative

controls?• How important are accessories?• How should I choose the company to buy from?• What alternatives are there to a digital camera?• How do I use the features my camera has?

Page 8: Digital photographer

1. WHAT IS A DIGITAL PHOTOGRAPH?

• The digital photograph, is a good place to begin understanding the whole digital photography process.

PIXELS-DOTS ARE ALL THERE • Digital photographs are made up of hundreds of

thousands or millions of tiny squares called picture elements-or just pixels. Like the impressionists who painted wonderful scenes with small dabs of paint, your computer and printer can use these tiny pixels to display or print photographs. To do so, the computer divides the screen or printed page into a grid of pixels. It then uses the values stored in the digital photograph to specify the brightness and color of each pixel in this grid-a form of painting by number. Controlling, or addressing a grid of individual pixels in this way is called bit mapping and digital images are called bit-maps.

Page 9: Digital photographer

• Here you see a portrait of Amelia Earhart done entirely in jelly beans. Think of each jelly bean as a pixel and it's easy to see how dots can form images.

Page 10: Digital photographer

Image sizeThe quality of a digital image, whether printed or displayed on a screen, depends in part on the number of pixels used to create the image (sometimes referred to as resolution). More pixels add detailand sharpen edges.

The photo of the face (right) looks normal, but when the eye is enlarged too much (left) the pixels begin to show. Each pixel is a small square made up of a single color.

Page 11: Digital photographer

• The size of a photograph is specified in one of two ways-by its dimensions in pixels or by the total number of pixels it contains. For example, the same image can be said to have 1800 x 1600 pixels (where "x" is pronounced "by" as in "1800 by 1600"), or to contain 2.88-million pixels (1800 multiplied by 1600).

This digital image of a Monarch butterfly chrysalis is 1800 pixels wide and 1600 pixels tall. It's said to be 1800x1600.

Page 12: Digital photographer

2. WHY GO DIGITAL?• Once captured, digital

photographs are already in a format that makes them incredibly easy to distribute and use. For example, you can insert digital photographs into word processing documents, send them by e-mail to friends, or post them on a Web site where anyone in the world can see them.

A small digital camera is easy to carry so you'll have it when you see things you never expected to see.

Page 13: Digital photographer

• Digital cameras are becoming more than just cameras. Some digital cameras are capable of capturing not only still photographs, but also sound and even video-they are becoming more like multimedia recorders than cameras.

• In addition to displaying and distributing photographs, you can also use a photo-editing program to improve or alter them. For example, you can crop them, remove red-eye, change colors or contrast, and even add and delete elements. It's like having a darkroom with the lights on and without the chemicals.

Once you have captured an image in digital format, you can easily distribute, organize, store, and edit it.

Page 14: Digital photographer

THE THREE STEPS OF DIGITAL PHOTOGRAPHY Step 1. Inputting

photographs Input devices get photographs

or other data into a computer system. Eg:Digital still cameras capture photographs in a digital format

Step 2. Processing photographsOnce a photograph is in digital form, you can store it on your system and then edit or manipulate it with a photo-editing program such as Photoshop.

Step 3. Outputting photographsOnce an image is the way you want it, you can output it to share with others. Print the image on a color printer.

Page 15: Digital photographer

If you've been wondering digital photography is spreading faster than an ordinary once, here are just some of the reasons.

• Immediately review your images on the camera's preview screen. Be more confident because you can check your pictures immediately to see if you got what you wanted.

• Connect the camera to a TV and show your images as a slide show.• Connect the camera to a microscope to display dramatically enlarged images on a

large-screen TV. • Stitch together panoramas from multiple pictures of the same scene. • Print the image on a color printer. • Create 3D stereo images to display on the screen. • Create animations to display on the screen. • Save money by not buying rolls and rolls of film and paying for development. • Save time because you don't have to make two trips to the store to drop off and then

pick up your pictures. • Choose just the best images for printing. • Be an environmentalist by not using the toxic chemicals used in traditional

photography.• Don't wait to finish a roll before having it processed. (Or waste unexposed film when

you can't wait.) • Capture sounds and even short videos with the same camera. • Improve or alter your images with a photo-editing program. • Hand the camera to the kids, take weird and unusual angles, shoot without looking

through the viewfinder. There are no film costs to think about. • Insert the photograph into a word processing or desktop publishing document. • Post the photograph on a Web site or a photo network. • E-mail the photograph to friends or family members. • Store the photograph on your system for later use.

Page 16: Digital photographer

3. IMAGE SENSORS•Digital cameras are very much like the still more familiar 35mm film cameras. Both contain a lens, an aperture, and a shutter. The lens brings light from the scene into focus inside the camera so it can expose an image. The aperture is a hole that can be made smaller or larger to control the amount of light entering the camera. The shutter is a device that can be opened or closed to control the length of time the light enters.

Film camera Digital camera

Page 17: Digital photographer

• The big difference between traditional film cameras and digital cameras is how they capture the image. Instead of film, digital cameras use a solid-state device called an image sensor, usually a charge-couple device (CCD). On the surface of each of these fingernail-sized silicon chips is a grid containing hundreds of thousands or millions of photosensitive diodes called photosites, photoelements, or pixels. Each photosite captures a single pixel in the photograph to be.

An image sensor sits against a background enlargement of its square pixels, each capable of capturing one pixel in the final image. Courtesy of IBM.

Page 18: Digital photographer

When the shutter opens, light strikes the image sensor to form the image. Courtesy of Canon.

The gray scale contains a range of 256 tones from pure white to pure black.It may be surprising, but pixels on an image sensor can only capture brightness, not color. They record only the gray scale-a series of 256 increasingly darker tones ranging from pure white to pure black. How the camera creates a color image from the brightness recorded by each pixel is an interesting story.

Page 19: Digital photographer

RGB uses additive colors. When all three are mixed in equal amounts, they form white. When red and green overlap, the form yellow, and so on. To see how this works, visit Konica's interactive presentation by clicking the MoreInfo button below.

WHAT IS COLOR?

Page 20: Digital photographer

FROM BLACK AND WHITE TO COLORSince daylight is made up of red, green, and blue light, placing red, green, and blue filters over individual pixels on the image sensor can create color images.

Colored filters cover each photosite on the image sensor so the photosites only capture the brightness of the light that passes through. The lenses on top of each pixel are used to collect light and make the sensor more sensitive.

Page 21: Digital photographer

With the filters in place, each pixel can record only the brightness of the light that matches its filter and passes through it while other colors are blocked. For example, a pixel with a red filter knows only the brightness of the red light that strikes it. To figure out what color each pixel really is, a process called interpolation uses the colors of neighboring pixels to calculate the two colors that the pixel didn't record directly. By combining these two interpolated colors with the color measured by the site directly, the full color of the pixel can be calculated. "I'm bright red and the green and blue pixels around me are also bright so that must mean I'm really a white pixel."

Here the full color of a green pixel is about to be interpolated from the eight pixels that surround it.

Page 22: Digital photographer

There's a computer in your camera

Each time you take a picture millions of calculations have to be made in just a few seconds. It's these calculations that make it possible for the camera to preview, capture, compress, filter, store, transfer, and display the image. All of these calculations are performed by a microprocessor in the camera that's similar to the one in your desktop computer.

Page 23: Digital photographer

The CCD shifts one whole row at a time into the readout register. The readout register then shifts one pixel at a time to the output amplifier.

Page 24: Digital photographer

4.TYPES OF DIGITAL CAMERAS

• Point and shoot cameras – Less cost – Automatic– Resolution upto 3-4 million

pixels

Prosumer camerascreative controls5-6 million pixels

Page 25: Digital photographer

Digital video cameras The Sony DCR-TRV33 MiniDV •captures 1152 x 864 pixel still images. •video

Specialty cameras Cell phones like this one from Nokia are now featuring built-in cameras.

Novelty Cameras

Casio makes a camera watch that can capture small images up to 176 x 144 pixels and can store about 100 of them

Page 26: Digital photographer

5. IMAGE STORAGE Flash card storage

Memory card storage cases Hard disk storage

Optical disc storage Temporary Storage

Page 27: Digital photographer

6. DOWNLOADING IMAGES

Cables. Most cameras now come with a USB or FireWire port that you can use to connect the camera to the computer with a thin cable.

Page 28: Digital photographer

7. IMAGE COMPRESSION

• What is compression?• During compression, data that is

duplicated or that has no value is eliminated or saved in a shorter form, greatly reducing a file’s size.

• There are two forms of compression—lossless and lossy—and digital cameras use both forms.

Page 29: Digital photographer

8. PREVIEW SCREENS & VIEWFINDERS

LCD monitors let you see the image you just took and scroll through those stored in the camera.

Some cameras have monitors that swing out and swivel so you can position it at almost any angle--even facing frontward for a self portrait

Page 30: Digital photographer

9. LENSES Focal length• One of the most important characteristics of any lens

is its focal length. It's the focal length that determines a lens' angle of view-wide angle, normal, or telephoto.

As the focal length of a lens increases, its angle of view decreases. Here the short focal length lenses are on the left and the long focal length lenses are on the right. As you move from left to right the focal length increases and the field of view decreases.

Page 31: Digital photographer

10. BATTERIES The best batteries for cameras that accept AA batteries are clearly NiMH (nickel-metal hydride).

Battery chargerSome cameras come with their own chargers, but you might be able to find a better one with more features.

Page 32: Digital photographer

11. OTHER FEATURES

Look and feel

Size and weightOrientation sensor

Page 33: Digital photographer

Panorama mode Some panoramas are created by throwing away much of the captured image. (The black bands shown here.) When just the central strip is printed, it looks panoramic.

Multiple exposures This double-exposure puts Clover the cat next to the woman hiding behind the sheet of paper.

Page 34: Digital photographer

With addition to the above the following are some other features that should be noted.Self-timer/remote controlDate/time indicatorsSound recordingImage modes

and

Software Photoshop is the photo editing program against which all others are compared.

Page 35: Digital photographer

12. IS IT TIME TO BUY?Point to Consider Digital Camera Scanned Film

Immediacy Images are instantly available Images are available only after the roll is finished and processed

Resolution Resolution (detail) is low compared to film. Even digital cameras with over 1 million pixels are only great for 4 x 6 prints and good for 8 x 10s.

Excellent, many times higher than digital cameras. You can make 16 x 20-inch prints from 35 mm film if you shoot with a tripod.

Storage Magnetic or optical media adds to total image costs.

Negatives and slides are self storing, but slides must be put in sheet holders for protection, convenience, and ease of use.

Longevity Storage media may not be readable in the future as formats and devices change. Prints are not as stable as silver-based prints.

Slides and prints can always be viewed without devices; and slides, negatives, and prints should easily last a century or more.

Cost Film and processing cost is eliminated so you can shoot at no cost. However, costs are incurred when you store or print. Battery costs will also be a factor over the life of the camera.

Film must be both purchased and processed. However, at that point there are no additional costs unless you want additional prints or enlargements.

Creative Controls All but the most expensive consumer level digital cameras lack all of the controls found on the least expensive SLR cameras. Choice of lenses is very limited.

Professional level controls are found on even the cheapest 35 mm SLR. There is also an extensive choice of lenses for most models.

Page 36: Digital photographer

13. THE RULES OF THE SHOPPING GAME

Advertising claimsCheck Reseller RankingsCheck price comparison sitesExplore on-line auctionsWatch out for unbundlingAvoid gray market productsCheck postage ratesAvoid extended warrantiesCheck return policies, restocking feesBuy no extrasShop locally-support your local economy

Page 37: Digital photographer

14.Digital photography Web sites

Steves Digicams

Steve Sanders runs one of the most popular sites on the Web. Not only does he have up-to-the-minute news, his discussion forums are among the most heavily visited. This is a must visit for anyone exploring thew world of digital photography.

Page 38: Digital photographer