2. Digital and Analog Technology
Analog Digital
Image
Structure
Silver grains or dye clouds of
varying size distributed in a
random pattern.
Same sized sensor pixels arranged
in a regular grid or raster array.
Color
Recording
Colors in the scene separated
by red, green and blue
sensitive layers.
Colors in the scene separated by
Bayer pattern of red, green and
blue filters.
Color
Reproduction
Dye clouds of cyan, magenta,
and yellow.
Interpolated from color filter
array.
Image
Amplification
Development by chemical
action.
Electronic and digital process.
Image
Quality
Depends on film speed, grain
structure, and processing
system.
Depends on sensor resolutions and
interpolation methods, also
compression implied, if used.
Storage Image fixed by removing
unexposed color dye.
Image is stored memory chips,
hard-drive or cloud storage.
5. Advantage and
Disadvantage of Digital
Shooting
Advantages Disadvantages
I. No purchases of film stock or lab
costs
The digital cameras are much more
costly than film camera.
II. Darkroom facilities are not required. Resolution is low with comparison to
the film.
III. Image storage and transmission is
easy.
Unlike processed film you cannot
physically hold up and study your
image any where and at any time
IV. Can be edited easily using editing
software in a PC.
Digital files may deteriorates
knowingly.
V. Need not to depend on film speed,
grain structure, and processing
system.
Technological upgrades are essential
over the time.
VI. Immense opportunity for creativity. Creative possibilities are limited.
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Digital Pathways
Digital Pathways through photography start with the digital capture of an image.
Primarily you will capture or take, an image using your di9ital camera . But you may
also obtain images downloaded from a website or sent wirelessly by mobile phones.
Image transferred from a video camera or copied from storage media such as cd, dvd
or flash memories.
Being digital, your image is similar to any word-processor document, spreadsheet, or
other computer file. You can store it on your computer hard-disk, as well on any
removeable medium; you can exchange the file between networked computers-
wirelessly or through cables; and you can sent it around the world via the internet. Like
any computer file, however, it must be in a form that will be recognized by your
chosen software before you can use if for image editing, retouching, manipulation or
combine with text or print it out.
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Digital Pathways…
• Digital Pathways, simply speaking how digital image is transmit form the source to the
desired destination using appropriate hardware, software and firewall.
• Digital Pathways is sometime associated with digital workflow. The crucial process of
taking an image from the camera’s sensor to the screen-and beyond is often described
as ‘workflow’. Workflow reflects photographer’s choice of the different software
available and his or her particular way of using it. The workflow may also vary with
assignments, so the way in which images are processed for a sports assignment when
pictures need to be transmitted during the game will vary from a features assignment,
whent it possible to perform a more considered edit at the conclusion of the shoot.
13. Digital Sensor
Types of Camera Sensors
There are two main types of camera
sensors: CCD (charge-coupled device)
sensors and CMOS (complementary metal-
oxide semiconductor) sensors.
1. CCD sensor: CCD sensors produce high
image quality with low noise and good
dynamic range. CCD sensors are common
for medium-format cameras. They consume
far more power than CMOS sensors.
2. CMOS sensor: CMOS sensors are
considerably more common than CCD
sensors, and they consume less power and
excel in high-speed burst shooting mode.
Though they have a lower sensitivity to light
and more grain, they have a quicker data
rate and are cheaper to produce.
14. Digital Sensor Cont..
6Ways Sensor Size ImpactsYour Photos
The size of the sensor on your camera has an enormous effect on your
photography, impacting the following elements:
1. Image resolution: Resolution is dependent on how many megapixels your
camera sensor holds—but what's a megapixel? Camera sensors contain millions of
“photosites” that capture light that is translated into pixels. A million of these
pixels equals one megapixel. The larger your camera's sensor, the larger the
photosites, the more resultant megapixels, which allow for a better image and a
higher resolution. High resolution is important to ensure that your images are high
quality even when you blow up a photo to a larger size.
2. Depth of field: Depth of field is the distance in an image where objects appear
“acceptably in focus” or have a level of “acceptable sharpness.” If other factors are
the same—aperture, focal length, camera-subject distance—a larger sensor will
have a shallower depth of field (since, in order to fill the frame, larger sensors
require you to either be closer to your subject or to use a longer focal length).
Correspondingly, cameras with smaller sensors have larger depths of field. A full-
frame camera sensor will provide you with the most flexibility when it comes to
depth of field.
How Image Sensor Size Affects the Quality ofYour Photos?
Sensor size is an important factor when it comes to selecting a digital camera
since it directly impacts the quality of your photos. But is a bigger sensor
always better? There are pros and cons to different sensor sizes, and it pays to
be familiar with them so you know which size is best for your needs.
15. Digital Sensor Cont..
3. Low-light performance: A large sensor contains larger photosites, which
enhance the camera's ability to capture low-light photos in comparison to a small
sensor.
4. Crop factor: Crop factor is the ratio of the sensor size to a full-frame image
sensor. Smaller sensors have a lower angle of view (how much of the frame is
visible when taking a photo), which means less of your frame is captured compared
to a full-frame sensor.
5. Dynamic range and image noise: Larger sensors contain larger photosites,
which increase the camera's dynamic range and decrease image noise. Dynamic
range is the maximum difference between a photo's lightest and darkest tones, so
a greater range is a positive attribute. Image noise is random specks of brightness
or color, so less image noise is also a positive characteristic.
6. Camera size and weight: While larger sensors have many benefits to your
finished photos, don't forget to take into account that a larger sensor requires a
larger lens and a potentially larger camera housing.The extra size and weight can
be a nuisance for certain types of photography—like travel and wildlife
photography—that require carrying your gear for long periods of time.
How Image Sensor Size Affects the Quality ofYour Photos?.......
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What is Dynamic Range?
Essentially, dynamic range is how far the brightest spots in your image can vary from the darkest spots in your image and still
maintain proper details in a single exposure.The more you have, the more you can capture scenes with a great contrast
between lights and darks.This often comes into play when shooting sunsets and sunrises since the sky is usually bright and the
foreground is usually dark.
If you’ve ever had to take a photograph on a bright sunny day, chances are pretty high that you would have lost detail, possibly
in the shadows or in the highlights, perhaps even both.This is not an exposure problem on your part. It’s more likely a limitation
of the dynamic range of your camera. Almost all cameras will come up against this problem at some time.
The 2Types of Dynamic Range
There are actually two dynamic ranges you need to think about. One is the dynamic range of the subject, the second is the
dynamic range of your camera.
The dynamic range of the subject is a measure of the range of light intensities from the shadows to the highlights. In low light
conditions, the dynamic range (that is the difference between the darkest and the latest part of the subject) is quite small. On a
bright sunny day, that range is much higher and is often outside the range of the camera.
Different cameras and different sensors will have bigger or smaller dynamic ranges. As long as the subject’s dynamic range
doesn’t exceed the camera’s dynamic range, you will be able to get a perfectly exposed photograph.
If the subject dynamic range is bigger than the camera’s dynamic range and one part of your subject will be either under or over
exposed.You can easily tell if the subject’s dynamic range exceeds that of your camera by using the histogram on your rear
screen.
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5 Standard Image Sensor Sizes
1. 35mm full-frame (36 x 24mm): Full-frame is the largest sensor size available and comes in both DSLR cameras and mirrorless
cameras.There's no crop factor with a full-frame sensor, meaning everything visible in the viewfinder appears in your photo.
The large sensor typically means the camera and lens will be bigger and heavier, so keep that in mind if your photography
requires long periods of shooting. Combining a wide aperture lens with a full-frame sensor gives you an exceptionally shallow
depth of field.
2. APS-H (28.1 x 18.7mm): Short for "active pixel sensor," the APS-H is a large sensor available in both fixed and
interchangeable lens cameras. It has a 1.3x crop factor and has a high ISO capability, resulting in less noise.
3. APS-C (size varies): APS-C cameras are an especially popular mid-range camera choice for amateur photographers who wish
to have some perks of a professional-level camera without overspending. Note that APS-C sensors come in different sizes
depending on the brand—Canon APS-C sensors measure 22.2 x 14.8mm and Nikon, Sony, Fujifilm, and Pentax sensors are
around 23.5 x 15.6mm.
4. FourThirds and Micro FourThirds (17.3 x 13mm):The original FourThirds System sensor is for DSLR cameras, while the
Micro FourThirds System is for mirrorless cameras.The Micro FourThirds system has a 2x crop factor and is a good choice for
still photography and high-level video recording.
5. One inch (9 x 12mm): A high-end compact camera with a 2.7x crop factor, its sensor is large for a compact camera, producing
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Pixel:
• The image seen on a computer screen is composed of tiny individual elements called pixels (derived from ‘picture
elements’. ‘Pic’ from Picture and ‘el’ from element).This is the smallest unit of any raster image.
• It corresponds to a grain of silver in a silver halides image.
• Each pixel has unique color, which is specified as proportion of the three primary colors: Red, Green and Blue. By
combining different amounts of each of the primary colors, almost any color can be generated. So each pixel has a size, an
address and a color spectrum.
• The ability to change pixel size, location and color makes it possible to manipulate digital images. A digital image is usually
composed of millions of individual pixel, so it is also known as building block or founding unit of a digital image.
• The smallest unit of data in an image file or on a computer monitor is one pixel. A million pixels means a Megapixel
denoted by MP, so it is a manageable way of describing very large numbers of pixels.
• For example: a 5-Megapixel camera is one that will produce 5 million pixels of image data.
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Pixel Cont….
• The pixel -- a word invented from picture element -- is the basic unit of programmable color on a computer display or in a
digital image.
• Each pixel is a square that's arranged in a uniformly two-dimensional grid. Each pixel has a logical address. (Think of it as a
logical -- rather than a physical -- unit.)
• Pixels are the smallest unit in a digital display. Up to millions of pixels make up an image or video on a device's screen.
Each pixel comprises a subpixel that emits a red, green and blue (RGB) color, which displays at different intensities.
• The RGB color components make up the gamut of different colors that appear on a display or computer monitor.
When referencing the resolution of a display, numbers like 1920 x 1080 refer to the number of pixels.
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Pixel Cont….
How do pixels work, and how are they used?
• The number of pixels determines the resolution of a computer monitor o,TV screen or digital image, and generally the
more pixels, the clearer and sharper the image.The resolution of the newest 8K full ultra-high-definitionTVs on the
market is approximately 33 million pixels -- or 7680 x 4320.
• The number of pixels is calculated by multiplying the horizontal and vertical pixel measurements. For example: 1,920
horizontal pixels and 1,080 vertical pixels, which totals 2,073,600.
• Other common display resolutions include the following:
480p, which is standard definition, is 640 x 480 and is often used for small mobile devices;
720p, which is HD, is 1280 x 720;
1440p, which is 2550 x 1440 and considered quarter HD, is often used for PC gaming monitors; and
4K video resolution, which is ultra HD, is 3840 x 2160 pixels.
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Each pixel is made up of a red, green and blue subpixel that lights up at different intensities to create different colors.
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Pixel Cont….
• The specific color information that a pixel describes is some blend of three components of the color spectrum -- RGB.
Up to three bytes of data are allocated to specify a pixel's color, one byte for each major color component. A true
color or 24-bit color system uses all three bytes. However, many color display systems use only one byte, which limits
the display to 256 different colors.
• A bitmap is a file that indicates a color for each pixel along the horizontal axis or row -- called the x coordinate -- and a
color for each pixel along the vertical axis -- called the y coordinate. A GIF file, for example, contains a bitmap of an
image along with other data.
How big is a pixel?
The physical size of a pixel depends on the set resolution for the display screen. If the display is set to its maximum
resolution, the physical size of a pixel will equal the dot pitch, or the dot size, of the display. But if the resolution is set to
something less than the maximum resolution, a pixel will be larger than the physical size of the screen's dot -- that is, a
pixel will use more than one dot.
What is a megapixel?
A megapixel (MP) is a million pixels.The term megapixel comes up most often in photography; however, screen resolutions
can be measured in megapixels. For example, 4K is approximately 12 MP and 1080p is 2.1 MP. In photography, megapixels
typically refer to the resolution of an image and the number of image sensor elements in digital cameras. For example,the
Sony A7 III camera can take 24.2 MP photos, which is 24,200,000 pixels.The Nikon Z9 is a 45.7MP full-frame pro sports
mirrorless camera: a high speed, 8K-shooting
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Pixel Cont….
Smartphones typically have 12 MP cameras, while interchangeable-lens cameras typically have anywhere from 20-60 MP.
Smaller action cameras like GoPros or Insta360 cameras can range from 12-48 MP.
The difference between PPI and DPI
Screen image sharpness is sometimes expressed as pixels per inch (PPI). PPI and dots per inch (DPI) are two similar and
commonly conflated concepts. PPI is the number of pixels contained in one inch of a digital image. By contrast, DPI is the
number of printed dots within one inch of a printed image.The main difference between the two terms is that PPI is the
quality of a digital image displayed on-screen, while DPI is the quality of a physical, printed image.The dots in DPI refer to
the number of printed dots of ink.
Although DPI is technically a term used for printing physical images, it has been misused so often that it's synonymous with
PPI.
According to Sony, there are two reasons for the confusion between the two terms. One reason is that even though PPI
refers to digital image quality, it still has an effect on an image when printed out, as prints with a higher MP count may have
finer details.The second reason is that some professional print services mistakenly request images be a specific DPI in order
to be printed, when they should instead be using the term PPI.
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What is bit depth?
Bit depth is one of the most fundamental and important parameters you're likely to come across in photography and videography.Before we
compare the various options, lets first discuss what the naming means. A “bit” is a computer’s way of storing information as a 1 or 0. A single
bit isn’t really good for anything beyond “yes” or “no” because it can only have 2 values. If it was a pixel, it would be pure black or pure white.
Not very useful.
To describe something complex, we can combine multiple bits. Every time we add another bit, the number of potential combinations
doubles. A single bit has 2 possible values, 0 or 1. When you combine 2 bits, then you can have four possible values (00, 01, 10, and 11). When
you combine 3 bits, you can have eight possible values (000, 001, 010, 011, 100, 101, 110, and 111). And so on. In general, the number of
possible choices is 2 raised to the number of bits. So “8-bit” = 28 = 256 possible integer values. In Photoshop, this is represented as integers 0-
255 (internally, this is binary 00000000-11111111 to the computer).
So “bit-depth” determines the smallest changes you can make, relative to some range of values. If our scale is brightness from pure black to
pure white, then the 4 values we get from a 2-bit number would include: black, dark mid-tones, light mid-tones, and white. This is a pretty
unsmooth and not very useful for a photograph. But if we have enough bits, we have enough gray values to make what appears to be a
perfectly smooth gradient from black to white.
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The large number of pixel the
greater the file size and higher
the resolution of detail in the
image
Capturing Images
On exposure to the
light, electrical
charges are
generated in a
proportion to how
much light each
pixel receives to
form an image
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Types of Digital Image
2. File format
a. Raster
b. Vector
1. Numbers of Bit
Representation
2. File format
1. Number of Bit
Representation
a. Binary Image
b. Gray-Scale
c. Color Image
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Types of images on the base of bit Representation
1. Binary Images
It is the simplest type of image. It takes only two values i.e, Black and White or 0 and 1.The binary image consists of a 1-bit
image and it takes only 1 binary digit to represent a pixel. Binary images are mostly used for general shape or outline.
For Example: OpticalCharacter Recognition (OCR).
Binary images are generated using threshold operation.When a pixel is above the threshold value, then it is turned
white('1') and which are below the threshold value then they are turned black('0')
2. Gray-scale images
Grayscale images are monochrome images, Means they have only one color. Grayscale images do not contain any
information about color. Each pixel determines available different grey levels.
A normal grayscale image contains 8 bits/pixel data, which has 256 different grey levels. In medical images and astronomy,
12 or 16 bits/pixel images are used.
3. Colour images
Colour images are three band monochrome images in which, each band contains a
different color and the actual information is stored in the digital image.The color images contain gray level information in
each spectral band.
The images are represented as red, green and blue (RGB images). And each color image has
24 bits/pixel means 8 bits for each of the three color band(RGB).
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12121
Types of images on the base of File Format
Vector and Raster
All digital image files fall into one of two categories: vector or raster. Each format has advantages and disadvantages in
different situations, so knowing the properties of each can help determine which format is the best choice for any project.
Vector files are most useful when a graphic needs to be able to handle resizing, as they retain crisp detail when scaled to
any size.Vector format is an excellent choice for digital illustrations such as logos.
A vector file can be converted to a raster file, but it will permanently lose the advantages of the vector format.
Common vector file extensions: SVG, EPS, and EMF
SVG — web-based vector format
EPS — Adobe-based vector format
EMF — Microsoft Office-based vector format
Raster
Raster images are best for complex images like photographs, and are more likely to be a widely compatible file format
(such as JPG). However, raster images lose detail and become increasingly blurry when enlarged.
Although a vector image can be saved as a raster image, it is not possible to convert a raster image into a vector image.
Raster files saved as vector file formats will still be raster files. Most images on the web are raster files.
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Common raster file extensions: JPG, PNG, andTIFF
JPG — compressed raster format, often used for photos
Best for web use
Small file size
Universal — compatible with most software
Most images on stock photography websites will be downloaded as JPG files
PNG — raster format good for illustrations or icons
supports transparency, unlike JPG
Best for web use
Small file size
TIFF — raster format that is best for high-resolution printing
Great for professional print use, especially when preserving crisp image detail is important
Large file size
Digital File Formats
