Digital Photography Basics
Through the feedback received from the readers and some of my friends, I understand that most of them need some basic information. These few lines are for those who are already familiar with general photography and need to know a few things special to digital camera.
INTRODUCTION
In the recent past, it was quite a task to shoot or convert analogue photos/ movies into digital format. Now, any one can directly acquire high definition digital images/ movies with the help of affordable digital cameras. These images in the form of bits & bytes ( or 0s and 1s) can be sent/ viewed through a computer and do not require films for storing purpose.
Being a film-less camera, Digital Camera is light weight, compact, hassle free and requires less power for its operation and consequently battery lasts longer. Once we purchase a Digital Camera, the rest of our photography become free of cost as no input material, like photographic film, printing paper, developer or fixer is required.
We may experiment with by taking, retouching photographs as many times as we desire without incurring any expenses (if we have rechargeable battery).
UNDERSTANDING RESOLUTION AND MEGAPIXEL
In the photographic film or printed photograph, we judge its quality and ability to enlarge by dots per inch it contain. In digital image we judge the same thing by pixels it contains and call it resolution. Mega pixels mean one million pixels. A digital camera having resolution of 1216x912 pixels is called 1 Mega pixel camera.
With the resolution of 1600x1200 (almost 2 Megapixels), we can print a 4x5 inch photograph with the same quality that we would get from a photo lab. The current standard Digital Cameras are 4 Megapixel (2240x1680) cameras and we may obtain a good quality photograph upto 16x20 inches.
Top of the line digital cameras upto 12 MP are available in the market and we may obtain up to 14x9 inch print with this resolution with no loss of picture quality. However, it may be noted that emailing pictures does not necessarily require high resolution. Normally 1 mega pixel resolution is used for sending large images.
Increasing resolution and quality of pictures generate large amount of data and more space is required to store it. To solve this problem, almost all digital cameras have option to store images in a compressed format called JPG. The more we compress the size of image file, the space required to store it is reduced. Most of the photos stored or transferred through internet are in JPG format. However, quality of image suffers with the increased compression. Following chart may explain it:
DIGITAL AND OPTICAL ZOOM
A digital camera may have optical as well as digital zoom.
Optical Zoom
The Optical Zoom occurs when we change focal length of the lens. A zoom lens is any lens which has an adjustable focal length. A 50mm lens gives a natural view of the subject. When we increase focal length, the subject appears bigger and total covering area become smaller. Similarly, decreasing the focal length decreases the magnification but increases covering area.
Digital Zoom
Digital Zoom in Digital cameras does not change focal length. It acquires information (pixels) from the centre of the sensor and interpolates this data into full size image.
ISO or ASA
ISO is how sensitive your digital camera is to light. Up to 1980, the term ASA was used to determine how sensitive your film is to light. In films, normal ISO (ASA) is 50 to 200. Higher ISO films (like ISO 400 & 1000) are also available to shoot fast moving objects and low light photography.
Digital Cameras are more sensitive to light than film or fixed-lens digital cameras, so their slowest ISO is often ISO 200. At present, top of the line Digital cameras are ISO 1600 feature. we need slower ISO to capture subtle shades and reduce graininess.
Through the feedback received from the readers and some of my friends, I understand that most of them need some basic information. These few lines are for those who are already familiar with general photography and need to know a few things special to digital camera.
INTRODUCTION
In the recent past, it was quite a task to shoot or convert analogue photos/ movies into digital format. Now, any one can directly acquire high definition digital images/ movies with the help of affordable digital cameras. These images in the form of bits & bytes ( or 0s and 1s) can be sent/ viewed through a computer and do not require films for storing purpose.
Being a film-less camera, Digital Camera is light weight, compact, hassle free and requires less power for its operation and consequently battery lasts longer. Once we purchase a Digital Camera, the rest of our photography become free of cost as no input material, like photographic film, printing paper, developer or fixer is required.
We may experiment with by taking, retouching photographs as many times as we desire without incurring any expenses (if we have rechargeable battery).
UNDERSTANDING RESOLUTION AND MEGAPIXEL
In the photographic film or printed photograph, we judge its quality and ability to enlarge by dots per inch it contain. In digital image we judge the same thing by pixels it contains and call it resolution. Mega pixels mean one million pixels. A digital camera having resolution of 1216x912 pixels is called 1 Mega pixel camera.
With the resolution of 1600x1200 (almost 2 Megapixels), we can print a 4x5 inch photograph with the same quality that we would get from a photo lab. The current standard Digital Cameras are 4 Megapixel (2240x1680) cameras and we may obtain a good quality photograph upto 16x20 inches.
Top of the line digital cameras upto 12 MP are available in the market and we may obtain up to 14x9 inch print with this resolution with no loss of picture quality. However, it may be noted that emailing pictures does not necessarily require high resolution. Normally 1 mega pixel resolution is used for sending large images.
Increasing resolution and quality of pictures generate large amount of data and more space is required to store it. To solve this problem, almost all digital cameras have option to store images in a compressed format called JPG. The more we compress the size of image file, the space required to store it is reduced. Most of the photos stored or transferred through internet are in JPG format. However, quality of image suffers with the increased compression. Following chart may explain it:
DIGITAL AND OPTICAL ZOOM
A digital camera may have optical as well as digital zoom.
Optical Zoom
The Optical Zoom occurs when we change focal length of the lens. A zoom lens is any lens which has an adjustable focal length. A 50mm lens gives a natural view of the subject. When we increase focal length, the subject appears bigger and total covering area become smaller. Similarly, decreasing the focal length decreases the magnification but increases covering area.
Digital Zoom
Digital Zoom in Digital cameras does not change focal length. It acquires information (pixels) from the centre of the sensor and interpolates this data into full size image.
ISO or ASA
ISO is how sensitive your digital camera is to light. Up to 1980, the term ASA was used to determine how sensitive your film is to light. In films, normal ISO (ASA) is 50 to 200. Higher ISO films (like ISO 400 & 1000) are also available to shoot fast moving objects and low light photography.
Digital Cameras are more sensitive to light than film or fixed-lens digital cameras, so their slowest ISO is often ISO 200. At present, top of the line Digital cameras are ISO 1600 feature. we need slower ISO to capture subtle shades and reduce graininess.
