Conventional (film) and digital photography are in many ways very similar, but in just as many ways, quite different. Both have their advantages, so in the foreseeable future, there will remain applications for each.
Conventional photography using chemically photo-sensitive film is a well known and highly developed quantity – very close to a perfected technology.
We know how to use it, how to get the best out of it, and how its life span can be optimised because it has been around for so long, used so much and had so much effort and expense spent on its development.
Digital photography is, on the other hand, a relatively new and radically different technique, which records images in the form of digital (i.e. 2 digit or binary) codes. In simple terms digital codes are similar to Morse code. One number or digit is indicated by a pulse of electricity, a second digit is indicated by no electrical pulse. By combining these pulses and lack of pulses into codes, we can, for example, create representations for letters of the alphabet; allowing us to write language or text on a computer. When we combine these electrical "pulses" and "no pulses" (or ‘ones’ and ‘zeros’) in more complex combinations, we can create more complex representations. These can include the colour, and degree of darkness or brightness in a single spot on a picture. When huge quantities of such dots are combined together, into a grid or array, we can then create a digital picture. (This is basically how digital photography works!) Each dot is referred to as a pixel (PICTURE ELEMENT) and is represented by ‘bits’ of data – thus the digital image array is often referred to as a ‘bitmap’.
As time passes, digital photography is becoming better and better and its imagery now rivals that of the best traditional silver halide based photography. However, due to its nature,some photographers still work with film.
The major difference between a "film" camera and a "digital" camera is, in very simple terms, that one captures the picture on film, while the other captures the picture on an image sensor and then stores it as data in a memory card. There are two main types of sensor – The CCD (or CHARGE COUPLED DEVICE) and the CMOS array (COMPLEMENTARY METAL OXIDE SEMICONDUCTOR ).
CCDs and CMOS – The sensors
A CCD is a grid of linked, light-sensitive silicon semiconductors (think transistors). It is effectively an electronic memory array that can be charged by light. It comprises an enormous number of elements (the pixels), each being sensitive to light. When light from the image being photographed passes through the lens into the camera, it hits the CCD, and the light is converted into small charges of electricity, varying in intensity according to the varying intensities of the different rays of light creating the image.
When you take a digital photograph, you are exposing the CCD to an image, and that image creates a network of different electrical pulses which can then be converted into a digital code and stored in the memory system of the camera. CCDs and CMOS sensors are essentially analogue devices which need to have their outputs digitised or encoded in order for them to be stored in memory. CCDs have long held prominence as the highest quality sensors, which produce the best results. Generally they have better light sensitivity than CMOS but because of their structure (each pixel passes its charge to the next, necessitating a piece by piece scanning process to encode the image) they take longer in image processing and use much more power.
Distance Education Course
DIGITAL PHOTOGRAPHY BPH202
- An external studies course to develop your ability to produce photographs using digital technology (digital or conventional photography combined with computer software and hardware for processing the photographs).
- Duration: 100 hours
- (study at your own pace, average time to complete this module is 4-6 months part time)
- COURSE AIMS
- To understand the scope and nature of digital photography
- To be able to select appropriate equipment for use in digital photography
- COURSE STRUCTURE
This course is divided into eleven lessons as follows:
- 1. Introduction To Digital Technology
- How images are captured and stored, categories of equipment & software, scope of applications
- 2. Equipment -getting started; deciding what you need
- CCD's, Image Sizes, Raster Images,, Video Cards, Colour depth, Computer terminology etc.
- 3. Digital Technology
- Colour, resolution, sensors ( how technology enables digital images to be captured).
- 4. Digital Cameras
- Image formation, lenses, camera stability, one shot cameras, 3 shot cameras, terminology
- (eg.DPI, DVD, Bit, EDO RAM, Plug In etc)
- 5. Taking Photographs
- Principles of Photo Composition, Creating effects, Default Setting, Compression of Data,
- Dithering, Halftones etc
- 6. Scanners
- Techniques which can be used for digitally capturing images from film photographs, or graphics
- 7. Uploading Images
- How digital images can be transferred effectively from a camera (or scanner) onto another device
- (eg. a computer, video monitor, television set, etc).
- 8. The Digital Darkroom
- Techniques that can be used to process digital photographs within a computer to achieve
- improved or changed images
- 9. Compositing & Imaging - Production & manipulation of images
- How digital photos can be manipulated and changed to produce altered images
- 10. Special Effects
- Scope and nature of special effects that can be created with digital photographs
- 11. Outputs & Applications- Printers, The Internet
- How and where digital photography can effectively be used.
- EQUIPMENT REQUIREMENTS
You will need access to a digital camera and some type of storage or output device during the course.
- This is required so that you can take some photographs on a digital camera and submit them as a print or as a digitised file. An inexpensive digital camera and a printer or 3.5 inch floppy disk would be a minimum. If you plant o purchase a digital camera, but have not yet decided what to buy, it is recommended that you delay buying a camera until you have completed Lesson 3 and commenced Lesson 4. It is also suggested that you ask your tutors advice as to which camera would best suit your needs. Access to a suitable computer is also advantageous but not essential.
- WHAT YOU WILL DO IN THIS COURSE
- Amongst other things you will do the following:
- Investigate software available for processing digital photographs
- Obtain literature on Adobe Photoshop and any two other types of software.
- Compare the different software options which you investigate.
- Develop a check list of what would be required if you were to purchase a digital camera for professional freelance photographic work (such as studio portraits and wedding photography)
- Review photographs you have taken in the past which have not been as successful as you would have liked. Consider what you might have done to improve the way in which the image was taken in each of these. Consider what advantages digital photography might have offered if you had taken these using a digital imaging rather than film.
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