20 Sep 08 Digital Camera Handling And Maintenance
Author: Roberto Sedycias
A photographic camera is an apparatus for taking photographs or moving film. All cameras have the same basic design - a lightproof container with a lens and a light-sensitive surface. A digital camera is different from a standard 35 mm SLR (single lens reflex) in the sense that digital cameras require no film rolls.
In earlier times careful planning went into taking pictures of an object but with a digital camera you can take a number of photographs and then select the best posture that you have captured while the rest of the pictures can always be deleted without involving any monetary loss. The pictures can then be transferred to your personal computer from where you can take out printouts if you have a color printer installed.
The quality of the photographs in a digital camera depends upon the camera resolution which is determined by pixels. Pixels or picture elements are any of the minute areas of uniform illumination of which an image on a digital display screen is composed. The greater the number of these pixels, the sharper is the image created. A digital camera which offers a resolution of 5 mega pixels is normally considered a good camera.
The weight of the digital camera also goes a long way in camera selection. Once upon a time digital cameras used to weigh one kilogram but with technological advancement they have become very compact and sleek. These modern cameras now come with zoom facilities. You can use digital zoom in any picture-taking mode to get up to 3X magnification beyond optical zoom.
You can do more with your digital camera like using different modes. General picture taking offers an excellent balance of image quality and ease of use. Point-and-shoot simplicity function is provided when taking pictures under special conditions. You can capture video with sound. You can view your favorite pictures. To capture far away scenes, the camera uses infinity auto focus. The camera automatically sets the focus distance depending on the zoom position.
Most digital cameras permit a white-balance setting which automatically transmits by inference which element should look white and which should look black. The lens is an integral part of any camera and determines the quality of the photographs. All digital cameras have LCD screens which can vary in size.
Care and maintenance of your digital camera is of utmost importance. If you suspect water has gotten inside the camera, remove the battery and memory card and allow all components to air-dry for at least 24 hours before using the camera. Blow lightly on the lens or LCD to get rid of dirt and dust. You should always wipe softly with a lint-free and soft cloth or lens cleaning tissue. Never use solutions unless intended particularly for camera lenses. Never allow chemicals such as sun tan lotion, to contact painted surfaces.
For digital camera, battery care is vital. Do not allow batteries to touch metal objects, including coins. Otherwise a battery may short circuit, discharge energy, become hot or leak. Always remove the battery when the product is stored for an extended period of time.
If your budget allows always buy a digital camera that provides you with higher resolutions, longer zoom lens and some other special features. Advanced consumer cameras usually require that you spend some time with the instruction manual to master all their capabilities, but they have few limitations.
Digital camera assures a user friendly working with pictures and videos. If accidentally you delete a picture you can use the undo delete function to retrieve it but this should be done immediately after you delete a single picture.
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20 Sep 08 Digital Camera Basics-images
Author: Brian Lee
In the past twenty years, most of the major technological breakthroughs in consumer electronics have been built around the same basic process: converting conventional analog information (represented by a fluctuating wave) into digital information (binary information represented by ones and zeros, or bits). This fundamental shift in technology has changed how we handle visual and audio information — it completely redefined what is possible.
The digital camera is one of the most notable examples of this shift because it is so truly different from its predecessor. Conventional film cameras depend entirely on chemical and mechanical processes — you don’t need any electricity whatsoever to operate them, other than for a flash. On the other hand, all digital cameras have a built-in computer, and all of them record images electronically.
The new approach has been enormously successful. Since film usually provides better picture quality, digital cameras have not completely replaced conventional cameras. But, as digital imaging technology has improved, and prices dramatically decreased, digital cameras have rapidly become more popular.
In this article, we’ll find out exactly what’s going on inside these amazing digital-age devices.
Understanding the Basics
Let’s say you want to take a picture and e-mail it to a friend. To do this, you need the image to be represented in the language that computers recognize — bits and bytes, or binary information. Essentially, a digital image is just a long string of 1s and 0s that represent all the tiny colored dots — or pixels — that collectively make up the image. If you want to get a picture into this form, you have two options:
1) You can take a photograph using a conventional film camera, take the film to a developing lab that processes the film chemically, prints it onto photographic paper, and then place the picture on a digital scanner to sample the print (record the pattern of light as a series of pixel values).
2) You can directly sample the original light that bounces off your subject, immediately breaking that light pattern down into a series of pixel values — in other words, you can use a digital camera.
At its most basic level, this is all there is to a digital camera. Just like a conventional film camera, it has a series of lenses that focus light to create an image of a scene. But instead of focusing this light onto a piece of film, it focuses it onto a semiconductor device that records light electronically. A computer then breaks this electronic information down into digital data. All the fun and interesting features of digital cameras come as a direct result of this process.
Instead of film, a digital camera has a sensor that converts light into electrical charges.
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. Without getting too technical, a simplified way to think about these sensors is to think of a 2-dimentional array of thousands or millions of tiny solar cells.
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 become a factor:
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. CCD sensors create high-quality, low-noise images. 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.
CMOS devices use several transistors at each pixel to amplify and move the charge using ordinary wires. The CMOS signal is digital, so it needs no ADC. 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.
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 larger pictures can be without becoming blurry or “grainy.” 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.
Exposure and Focus
Just as with film, a digital camera has to control the amount of light that reaches the sensor. The two components it uses to do this, the aperture and shutter speed, are also present on conventional cameras.
Aperture: The size of the opening in the camera. The aperture is automatic in most digital cameras, but some allow manual adjustment to give professionals and hobbyists more control over the final image.
Shutter speed: The amount of time that light can pass through the aperture. Unlike film, the light sensor in a digital camera can be reset electronically, so digital cameras have a digital shutter rather than a mechanical shutter.
These two aspects work together to capture the amount of light needed to make a good image. In photographic terms, they set the exposure of the sensor.
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19 Sep 08 Digital Camera Basics-resolution, Exposure, Focus, and Storage
Author: Brian Lee
The amount of detail that a 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 larger pictures can be without becoming blurry or “grainy.” High-end consumer cameras can capture over 12 million pixels. Some professional cameras support over 16 million pixels (megapixels), or 20 million pixels for large-format cameras. For comparison, it has been estimated that the quality of 35mm film is about 20 million pixels.
Exposure and Focus
Just as with film, a digital camera has to control the amount of light that reaches the sensor. The two components it uses to do this, the aperture and shutter speed, are also present on conventional cameras.
Aperture: The size of the opening in the camera. The aperture is automatic in most digital cameras, but some allow manual adjustment to give professionals and hobbyists more control over the final image.
Shutter speed: The amount of time that light can pass through the aperture. Unlike film, the light sensor in a digital camera can be reset electronically, so digital cameras have a digital shutter rather than a mechanical shutter.
These two aspects work together to capture the amount of light needed to make a good image. In photographic terms, they set the exposure of the sensor.
In addition to controlling the amount of light, the camera has to adjust the lenses to control how the light is focused on the sensor. In general, the lenses on digital cameras are very similar to conventional camera lenses — some digital cameras can even use conventional lenses. Most use automatic focusing techniques.
The focal length, however, is one important difference between the lens of a digital camera and the lens of a 35mm camera. The focal length is the distance between the lens and the surface of the sensor. Sensors from different manufacturers vary widely in size, but in general they’re smaller than a piece of 35mm film. In order to project the image onto a smaller sensor, the focal length is shortened by the same proportion.
Focal length also determines the magnification, or zoom, when you look through the camera. In 35mm cameras, a 50mm lens gives a natural view of the subject. Increasing the focal length increases the magnification, and objects appear to get closer. The reverse happens when decreasing the focal length. A zoom lens is any lens that has an adjustable focal length, and digital cameras can have optical or digital zoom — some have both. Some cameras also have macro focusing capability, meaning that the camera can take pictures from very close to the subject.
Digital cameras have one of four types of lenses:
1) Fixed-focus, fixed-zoom lenses - These are the kinds of lenses on disposable and inexpensive film cameras — inexpensive and great for snapshots, but fairly limited.
2) Optical-zoom lenses with automatic focus - Similar to the lens on a video camcorder, these have “wide” and “telephoto” options and automatic focus. The camera may or may not support manual focus. These actually change the focal length of the lens rather than just magnifying the information that hits the sensor.
3) Digital-zoom lenses - With digital zoom, the camera takes pixels from the center of the image sensor and interpolates (alters) them to make a full-sized image. Depending on the resolution of the image and the sensor, this approach may create a grainy or fuzzy image. You can manually do the same thing with image processing software — simply snap a picture, cut out the center and magnify it.
4) Replaceable lens systems - These are similar to the replaceable lenses on a 35mm camera. Some digital cameras can use 35mm camera lenses.
Most digital cameras have an LCD screen so you can view your picture right away. This is one of the great advantages of a digital camera — you get immediate feedback on what you capture. Of course, viewing the image on your camera would lose its charm if that’s all you could do. You want to be able to load the picture into your computer or send it directly to a printer. There are several ways to do this.
Although most of today’s cameras are capable of connecting through serial, parallel, SCSI, USB, or FireWire connections, they usually also use some sort of removable storage device. Digital cameras use a number of storage systems. These are like reusable, digital film, and they use a caddy or card reader to transfer the data to a computer. Many involve fixed or removable flash memory. Digital camera manufacturers often develop their own proprietary flash memory devices, including SmartMedia cards, CompactFlash cards and Memory Sticks. Other removable storage device include floppy disks, hard disks (external, or microdrives), and writeable CD’s and DVD’s.
Regardless of what type of storage they use, all digital cameras need lots of room for pictures. They usually store images in one of two formats — TIFF, which is uncompressed, and JPEG, which is compressed. Most cameras use the JPEG file format for storing pictures, and they sometimes offer quality settings (such as medium or high).
To make the most of their storage space, almost all digital cameras use some sort of additional data compression to make the files smaller. One compression routine takes advantage of patterns that repeat. The image can be reconstructed exactly as it was recorded, reducing the file size no more than 50%, often much less. Another compression routine called irrelevancy eliminates some of the more meaningless data, taking advantage of the fact that digital cameras record more information than the human eye can easily detect.
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18 Sep 08 Digital Camera: a Buyers’ Guide
Author: Russ Snapper
A digital camera takes still photographs or videos or both by recording the images on a light-sensitive sensor digitally. Most compact digital still cameras can record moving video and sound as well, apart from still photographs. The sales and popularity of digital cameras have increased now compared to the 35mm film cameras.
Digital cameras have a feature for viewing the image that is recorded immediately on the Camera display screen, the feature that is not available in film cameras. Other features include such as the facility to capture a lot of images on a small memory chip, record video along with sound, edit the images, delete the images not required etc. Digital cameras are now available along with many devices ranging from mobile phones and PDAs to vehicles.
The camera perhaps has been affected more by the digital technology than any other products. The digital cameras are not a new phenomenon. The first digital camera was released by Kodak in the U.S. market around 15 years ago. The DCS-100 model at that time with 1.3-mega pixels was available for about $13,000. The digital cameras have emerged with more features and are available at comparatively lesser prices, even to the extent of $80 at select stores.
The biggest benefit of Digital camera technology is the storage capability. You can view the photos on the camera itself, on a web page, a computer monitor, or on paper after printing. The digital camera can be connected to the printer directly through the USB port for printing pictures. People can afford to buy a digital camera today as the prices have fallen with the availability of more features.
It is important for you to know the issues of image resolution for comparing digital camera models. The unit of graphical representation used for displaying digital data by Digital cameras is called Mega Pixel (MP). More the mega pixels, the higher the resolution of the final image. Still you need to compare digital camera images recorded with your actual requirements.
Some typical resolutions found on Digital cameras are:
256×256 – This is available with very cheap cameras. Picture quality is unacceptable.
640×480 – Suitable for posting pictures over a web site or for sending pictures by email.
1216×912 – This resolution is good for printing pictures.
1600×1200 – This is a High resolution standard with around 2 million total pixels.
2240×1680 – This is available on most 4 mega pixel cameras.
4064×2704 – This is available on high-end digital camera with 11.1 mega pixels.
Some High-end consumer cameras can record pictures of over 12 million pixels. Most professional cameras have 16 million pixels. Large format cameras have 20 million pixels. For comparison sake, it is stated that the quality of 35mm film is approximately around 20 million pixels. Some types of Digital cameras are Point and Shoot, Semi-Professional, Bridge and SLR.
You need to know the complete package offered when you compare the prices of digital cameras. You can look for the availability of image-editing software, carry case, add-on Memory card and USB cable for working on your computer, when you want to compare the prices and the features offered. Other general features that you can look into are the availability of an LCD screen, a timer, a built-in flash, a date & time stamp, optical zoom feature and optical zoom lenses of good quality.
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