3. The camera obscura (Lat. dark chamber) was an optical device
used in drawing, and one of the ancestral threads leading to the
invention of photography. In English, today's photographic devices
are still known as "cameras"
4.
5. The principle of the camera obscura can be demonstrated with a
rudimentary type, just a box (which may be room-sized, or even
hangar sized) with a hole in one side. Light from only one part of a
scene will pass through the hole and strike a specific part of the back
wall. The projection is made on paper on which an artist can then
copy the image. The advantage of this technique is that the
perspective is accurate, thus greatly increasing the realism of the
image
6.
7. In camera terms, the light converges into the room through the hole
transmitting with it the object(s) facing it. The object will appear in full
colour but upside down on the projecting screen/wall opposite the hole
inside the dark room. The explanation is that light travels in a straight line
and when some of the rays reflected from a bright subject pass through
the small hole in thin material they do not scatter but cross and reform as
an upside down image on a flat white surface held parallel to the hole
9. A pinhole camera is a camera in which the lens is replaced by an
extremely small hole, pierced in very thin material. Light from a scene
passes through this single point, producing a more-or-less sharp
image on the rear of a light-proof box. The image is upside-down, as
in a conventional camera with a lens
10. do - is the distance of the object (from the pinhole)
di - is the distance of the image (from the pinhole)
ho - is the height of the object, hi - is the height of the image
11. The smaller the hole, the sharper the image, but the longer the
exposure required. Optimally, the size of the pinhole, or aperture,
should be 1/100 or less of the distance between it and the screen
12. A pinhole camera's shutter is usually manually operated because
of the lengthy exposure times, and consists of a flap of some light-
proof material to cover and uncover the pinhole. Typical exposures
range from 5 seconds to hours and sometimes days
14. The box camera is, with the exception of the pin hole camera, a
camera in its simplest form. The classic box camera is shaped
more or less like a box
15. A box camera has a simple optical system, often only in the
form of a simple meniscus lens. It usually lacks a focusing
system (fix-focus) as well as control of aperture and shutter
speeds. This makes it suitable for daylight photography only
16. The box cameras are the oldest class of photographic cameras.
The first camera ever used for making persistent photographic
images was the big wooden box camera used for experimental
photography in the mid-1820s
17. From the beginning amateurs were participating in the
photography business, at least as customers for photographic
material. But traveling was expensive, and camera equipment
was heavy, so that a camera was even not in the luggage of
many rich travelers. Circumstances had changed at the end of
the 19th century. Dry plates, roll film, drugstores with darkrooms
to rent, material and infrastructure were given to support a wider
spreading of amateur photography
18.
19.
20.
21. The Kodak introduced in 1888, the first commercially successful
box camera for roll film -- the advertising slogan being ‘You
press the button - we do the rest’
The Kodak Brownie, a long lasting series of classical box
cameras using roll film
24. ‘SLR’ – Single lens reflex
means that the same lens is used for viewing and taking
pictures
25. A camera where the photographer sees exactly the same image
that is exposed to the film and can adjust everything by turning
dials and clicking buttons. Since it doesn't need any electricity to
take a picture, a manual SLR camera provides an excellent
illustration of the fundamental processes of photography
26. A still film camera is made of three basic elements: an optical
element (the lens), a chemical element (the film) and a mechanical
element (the camera body itself). As we'll see, the only trick to
photography is calibrating and combining these elements in such a
way that they record a crisp, recognizable image
27.
28.
29.
30.
31.
32.
33.
34. Most point-and-shoot cameras are fully automatic. Conceptually,
automatic cameras are pretty much the same as fully manual
models, but everything is controlled by a central microprocessor
instead of the user
35. The central microprocessor receives information from the
autofocus system and the light meter. Then it activates several
small motors, which adjust the lens and open and close the
aperture. In modern cameras, this a pretty advanced computer
system
36. Traditional photography burdened photographers working at
remote locations without easy access to processing facilities, and
competition from television pressured photographers to deliver
images to newspapers with greater speed. Photo journalists at
remote locations often carried miniature photo labs and a means
of transmitting images through telephone lines
37. In 1981, Sony unveiled the first consumer camera to use a charge-
coupled device for imaging, eliminating the need for film: the Sony
Mavica. While the Mavica saved images to disk, the images were
displayed on television, and the camera was not fully digital
38. The Kodak Professional Digital Camera System (unofficially
named the DCS 100) was the first DSLR camera. It was mounted
on a Nikon F3 body and released by Kodak in May of 1991
39. In the past twenty years, most of the major technological
breakthroughs in consumer electronics have really been part of
one larger breakthrough. When you get down to it, CDs, DVDs,
HDTV, MP3s and DVRs are all built around the same basic
process: converting conventional analog information (represented
by a fluctuating wave) into digital information (represented by ones
and zeros, or bits)
40. This fundamental shift in technology totally changed how we
handle visual and audio information -- it completely redefined what
is possible
The digital camera is one of -the most remarkable instances of
this shift because it is so truly different from its predecessor
41. Conventional cameras depend entirely on chemical and
mechanical processes -- you don't even need electricity to operate
them. On the other hand, all digital cameras have a built-in
computer, and all of them record images electronically
42. Instead of film, a digital camera has a sensor that converts light
into electrical charges
43. CCD CMOS
The image sensor employed by most digital cameras is a charge
coupled device (CCD). Some cameras use complementary
metal oxide semiconductor (CMOS) technology instead. Both
CCD and CMOS image sensors convert light into electrons
44. Once the sensor converts the light into electrons, it reads the value
(accumulated charge) of each cell in the image. This is where the
differences between the two main sensor types kick in:
A CCD transports the charge across the chip and reads it at one corner
of the array. An analog-to-digital converter (ADC) then turns each
pixel's value into a digital value by measuring the amount of charge at
each photosite and converting that measurement to binary form
CMOS devices use several transistors at each pixel to amplify and move
the charge using more traditional wires. The CMOS signal is digital, so it
needs no ADC
45. Differences between the two types of sensors lead to a number of
pros and cons
CCD sensors create high-quality, low-noise images. CMOS sensors are
generally more susceptible to noise
Because each pixel on a CMOS sensor has several transistors located
next to it, the light sensitivity of a CMOS chip is lower. Many of the
photons hit the transistors instead of the photodiode
CMOS sensors traditionally consume little power. CCDs, on the other
hand, use a process that consumes lots of power. CCDs consume as
much as 100 times more power than an equivalent CMOS sensor
CCD sensors have been mass produced for a longer period of time, so
they are more mature. They tend to have higher quality pixels, and more
of them
46. The amount of detail that the camera can capture is called the
resolution, and it is measured in pixels. The more pixels a camera
has, the more detail it can capture and the pictures can be larger
without becoming blurry or ‘grainy’
48. 256x256 - Found on very cheap cameras, this resolution is so low that
the picture quality is almost always unacceptable. This is 65,000 total
pixels
640x480 - This is the low end on most "real" cameras. This resolution is
ideal for e-mailing pictures or posting pictures on a Web site
1216x912 - This is a "megapixel" image size -- 1,109,000 total pixels --
good for printing pictures
1600x1200 - With almost 2 million total pixels, this is "high resolution."
You can print a 4x5 inch print taken at this resolution with the same
quality that you would get from a photo lab
2240x1680 - Found on 4 megapixel cameras -- the current standard --
this allows even larger printed photos, with good quality prints upto
5.25x8 inches
4064x2704 - A top-of-the-line digital camera with 11.1 megapixels takes
pictures at this resolution. At this setting, you can create 13.5x9 inch
prints with no loss of picture quality
49. High-end consumer cameras can capture over 12 million pixels.
Some professional cameras support over 16 million pixels, or 20
million pixels for large-format cameras
For comparison, Hewlett Packard estimates that the quality of
35mm film is about 20 million pixels
50. Image sensors used in DSLRs come in a range of sizes
The largest are the ones used in "medium format" cameras,
typically via a "digital back" which can be used as an
alternative to a film back. Because of the manufacturing costs
of these large sensors the price of these cameras is typically
over Rs. 10,00,000
51. With the exception of medium format DSLRs, the largest sensors
are referred to as "full-frame", and are the same size as 35 mm
film; these sensors are used in quite expensive DSLRs such as the
Canon EOS-1Ds Mark III, the Canon EOS 5D, the Nikon D700,
and the Nikon D3
52. Most modern DSLRs use a smaller sensor commonly referred to
as APS-C sized, that is, approximately 22 mm × 15 mm, or about
40% of the area of a full-frame sensor
Other sensor sizes found in DSLRs include the ‘Four Thirds
System’ sensor at 26% of full frame, APS-H sensors at around
61% of full frame, and the ‘Foveon X3’ sensor at 33% of full frame
53. The sensors used in current DSLRs are much larger than the
sensors found in digicam-style cameras, most of which use
sensors known as 1/2.5", whose area is only 3% of a full frame
sensor. Even high-end digicams such as the Canon PowerShot G9
or the Nikon CoolPix P5000 use sensors that are approximately
5% and 4% of the area of a full frame sensor, respectively
54.
55. There is a connection between sensor size and image quality; in
general, a larger sensor provides lower noise, higher sensitivity, and
increased latitude and dynamic range
56. According to a survey made by Kodak in 2007, 75 percent of
professional photographers say they will continue to use film, even
though some embrace digital
57. According to the U.S. survey results, more than two-thirds (68
percent) of professional photographers prefer the results of film to
those of digital for certain applications including:
Film’s superiority in capturing more information on medium and
large format films (48 percent)
Capturing shadow and highlighting details (45 percent)
The wide exposure latitude of film (42 percent)
58. Digital point-and-shoot cameras have become widespread
consumer products, outselling film cameras, and including
new features such as video and audio recording
59. Kodak announced in January 2004 that it would no longer
sell reloadable 35 mm cameras in western Europe, Canada
and the United States after the end of that year
60. In January 2006, Nikon followed suit and announced that they
will stop the production of all but two models of their film
cameras: the low-end Nikon FM10, and the high-end Nikon F6
61. On May 25, 2006, Canon announced they will stop developing
new film SLR cameras
