Archive for the ‘Technology’ Category

The Magic Behind Digital Camera

Wednesday, December 10th, 2008
digital cameras
Harry Rockwell asked:

A digital camera, as opposed to a film or videotape camera, uses an electronic sensor to transform images (or video) into electronic data. Modern digital cameras are typically multifunctional and the same device can take photographs, video, and/or sound.

In 2005, digital cameras are starting to push traditional film cameras out of many markets. Shrinking device sizes have recently allowed miniaturized digital cameras to be included in multifunctional devices, such as cell phones and PDAs.

Classification

Digital cameras can be classified into several groups:

Video cameras

* Professional video cameras such as those used in television and movie production. These typically have multiple images sensors (one per color) to enhance resolution and color gamut. Professional video cameras usually do not have a built-in VCR or microphone.

* Camcorders used by amateurs. These are a combination of camera and VCR to create an all-in-one production unit. They generally include a microphone to record sound, and feature a small LCD to watch the video during filming and playback.

Still cameras

Digital still cameras are generally characterized by the use of flash memory and USB or Fire Wire for storage and transfer.

Most have a rear LCD for reviewing photographs. They are rated in mega pixels; that is, the product of their maximum resolution dimensions. The actual transfers to a host computer are commonly carried out using the USB mass storage device class (so that the camera appear as a drive) or using the Picture Transfer Protocol and its derivatives.

All use a CCD (for Charged Coupled Device) which is a chip comprised of a grid of phototransistors to sense the light intensities across the plane of focus of the camera lens.

There has recently been some application of a second kind of chip, called a CMOS (Complementary Metal-Oxide Semiconductor) sensor, and this chip is often differentiated from a CCD proper in that it uses less power and a different kind of light sensing material, however the differences are highly technical and many manufacturers still consider the CMOS chip a charged coupled device. For our purposes, a chip sensor is a CCD.

* Standard Digital Cameras: This encompasses most digital cameras. They are characterized by great ease in operation and easy focusing; this design allows for limited motion picture capability. They have an extended depth of field.

This allows objects at multiple depths to be in focus simultaneously, which accounts for much of their ease of focusing. It is also part of the reason professional photographers find their images flat or artificial-looking. They excel in landscape photography and casual use.

* Digital SLRs typically have a sensor nine times larger than that of a standard digital camera, and are targeted at professional photographers and enthusiasts. They resemble ordinary professional cameras in most ways, with replaceable flash and lens components, which give the user maximum control over light, focus and depth of field.

They are also bulkier and more expensive than their casual-use oriented counterparts. They are superb for portraiture and artistic photography because they can be customized for various applications with a comprehensive range of exchangeable lenses.

Professional modular digital camera systems

High-end digital camera backs used by professionals are usually separate devices from the camera bodies which they are used with. (This is because most of the large- and medium-format camera systems in professional use at the time that digital capture overtook film as the professional’s medium of choice were modular in nature, i.e. the camera body had multiple lenses, viewfinders, winders and backs available for use with it to fit different needs.)

Since the first backs were introduced there have been three main methods of “capturing” the image, each based on the hardware configuration of the particular back.

The first method is often called “Single Shot,” in reference to the number of times the camera’s sensor is exposed to the light passing through the camera lens.

Single Shot capture systems use either one CCD with a Bayer filter stamped onto it or three separate CCDs (one each for the primary additive colors Red, Green and Blue) which are exposed to the same image via a beam splitter.

The second method is referred to as “Multi-Shot” because the sensor is exposed to the image in a sequence of three or more openings of the lens aperture. There are several methods of application of the multi-shot technique.

The most common originally was to use a single CCD with three filters (once again red, green and blue) passed in front of the sensor in sequence to obtain the additive color information.

Another multiple shot method utilized a single CCD with a Bayer filter but actually moved the physical location of the sensor chip on the focus plane of the lens to “stitch” together a higher resolution image than the CCD would allow otherwise. A third version combined the two methods without stamping a Bayer filter onto the chip.

The third method is called “Scan” because the sensor moves across the focus plane much like the sensor of a desktop scanner.

These CCDs are usually referred to as “sticks” rather than “chips” because they utilize only a single row of pixels (more properly “photosites”) which are again “stamped” with the Bayer filter.

The choice of method for a given capture is of course determined largely by the subject matter. It is usually inappropriate to attempt to capture a subject which moves (like people or objects in motion) with anything but a single shot system.

However, the higher color fidelity and larger file sizes and resolutions available with multi-shot and scan-backs make them attractive for commercial photographers working with stationary subjects and large-format photographs.

Webcams

* Webcams are digital cameras attached to computers, used for video conferencing or other purposes. Webcams can capture full-motion video as well, and some models include microphones or zoom ability.

These devices range in price from very inexpensive to expensive higher-end models; many complex webcams have a servo-controlled base capable of tracking facial motion with the help of software.

Interpolation

Image color or resolution interpolation is used unless the camera uses a beam splitter single-shot approach, three-filter multi-shot approach, or Foveon X3 sensor.

The software specific to the camera interprets the information from the sensor to obtain a full color image. This is because in digital images, each pixel must have three values for luminous intensity, one each for the red, green, and blue channels. A normal sensor element cannot simultaneously record these three values.

The Bayer filter pattern is typically used. A Bayer filter pattern is a 2×2 pattern of light filters, with green ones at opposite corners and red and blue elsewhere.

The high proportion of green takes advantage of properties of the human visual system, which is determines brightness mostly from green and is far more sensitive to brightness than to hue or saturation.

Sometimes a 4-color filter pattern is used, often involving 2 different hues of green. This provides a wider color gamut, but requires a slightly more complicated interpolation process.

The luminous intensity color values not captured for each pixel can be interpolated (or guessed at) from the values of adjacent pixels which represent the color being calculated.

In some cases, extra resolution is interpolated into the image by shifting photosites off of a standard grid pattern so that photosites are adjacent to each other at 45 degree angles, and all three values are interpolated for “virtual” photosites which fall into the spaces at 90 degree angles from the actual photosites.

Connectivity

Many digital cameras can connect directly to a computer to transfer data. USB is the most widely used method, though some have a Fire wire port.

Integration

Some devices, like mobile phones integrates digital cameras. Mobile phone cameras are much more sold than standalone digital ones.

Storage

Digital cameras need memory to store data. The higher one goes in pixel size, the more memory will be needed. Cameras use a removable memory card to store data, but the cheapest and smallest cameras may simply use fixed internal memory instead. Some cameras come with inbuilt memory as well.

Autonomous devices

An autonomous device, such as a PictBridge printer, operates without need of a computer. The camera connects to the printer, which then downloads and prints its images. Some DVD recorders and television sets can read memory cards too.

How Do I Choose a Digital Camera?

Friday, September 5th, 2008
digital cameras
J Adams asked:


A digital camera might look like a film camera but they are actually quite different. Both freeze light to make a photograph. Film cameras do this chemically using film. Digital cameras use a light sensitive CCD or CMOS silicon chip to convert light and digital information into pixels.

Pixels are the tiniest areas of light that your digital camera can recognize and change into information. The greater amount of pixels the more detail and higher the resolution the photograph. A low resolution color printout of tree will show that it is green but in a high resolution photograph the leaves and texture of the bark will be more sharply defined.

With digital photographs your have the ability to use software like Adobe Photoshop Deluxe and Microsoft Picture to edit photos and make corrections.

Choosing Your Camera

Important considerations when choosing a digital camera are: What do you want the camera to do? What features do you require? How much do you wish to spend on your camera?

There are professional high end cameras that cost thousands of dollars, cheap throwaway cameras and a huge selection of mid-level cameras available to choose from.

Will you be photographing images for the internet and for email? Will your photos be printed? For regular print size snapshots and web photos a one to two megapixel camera will do. In fact for the web a lower megapixel would be better as higher resolution photos are slow to download.

Do you want a point-and-click camera? Are you someone who just wants to get the picture taken with the least amount of bother. Do you want a camera that does everything automatically and you simply have to press a button? Or, are you someone who would rather figure out the best settings for your camera and make the adjustments manually? It’s always best to find a camera that suits your purpose, need and ability.

High or Low Resolution

High end, high resolution cameras are good for photographs that are to be printed. The greater the number of pixels the higher the resolution. High resolution does not make sense on the web as the extra resolution does not make images appear any sharper. Also, high resolution photos are slow to download on the web.

To print your photographs you will need a good quality color printer. If photos are to be printed, high resolution does make a difference depending how large you want the picture to be. High resolution will give a large print better definition. High resolution cameras cost more. Expect to pay more for high resolution. You also need to check that your printer can handle high resolution prints.

Lenses

Low-end digital cameras have fixed focus lenses made of plastic. With these lenses everything is focused and you don’t need to make a decision what to focus on.

Variable focused lenses are made of glass or high quality plastic. These lenses focus on whatever object you are trying to capture in a photograph.

Most mid-range digital cameras come with auto focus and manual focus built in. Auto focus is for point-and-click photos of whatever is in the middle of the frame. Or, by turning the ring over the lens, you can manually focus the camera. These cameras allow users to switch between auto and manual focus.

Zoom Lenses

Digital cameras have optical zoom and digital zoom lenses. Optical zoom costs more, give a better quality picture, and works the same way as on non-digital cameras with lens adjustments. A digital zoom comes about when the camera makes calculations to manipulates the pixels. Digital zoom gives a less sharp image. Some cameras include both optical and digital zoom.

View Finder

The view finder is what you look through to see what you are photographing. The view finder on both digital and regular film cameras will approximate the picture your lens is viewing. Digital cameras will also come with an LCD display that you can use to check your photographs and decide weather or not to keep them.

Lighting

When it comes to lighting you might not want the camera to make the decision automatically for you. On an auto setting you camera might not make the best lighting choice given the location and environment. At times like this you can appreciate being able to switch between manual and automatic settings.

Digital cameras allow you to test exposure and view a picture on LCD prior to pressing the button fully and committing to a photograph.

Flash

There will be a built in flash that comes with your digital camera. In addition, the better cameras have a location for a flash attachment. This is a good option for producing better quality photographs.

Connecting to Your Computer

You will need a PC USB cable, or for Mac’s – Firewire or Mac USB cable, to connect to your computer. You will also need a cable adapter for your camera’s CF (Compact Flash) or SM (Smart Media) card .

The CF or SM cards are removable high capacity storage cards for your photos. Your camera will use one type of card or the other. Not both. Check to see which type of storage card your camera uses.

USB connections are fast and easy to set up. Older cameras connect through a serial port. USB is faster and does not require that the computer be rebooted before it recognizes the camera.

Batteries and AC Adapters

Digital cameras often come with rechargeable batteries. It is best to have two sets of batteries. One set to use while the other is recharging. AC adapters make it easy to plug into an electrical outlet when you are near by one.

Main Drawback of Digital Camera

The main drawback of digital cameras is shutter lag delays when the camera delays responding after you squeeze the button. It is possible you may miss the moment when photographing moving objects due to shutter lag. Some of the newer cameras are beginning to address the problem.

Select a camera that does what you want it to do, has features you will use and is priced in the range you want to pay. This will be the right camera for you. If your experience is limited and you do not want to take a lot of time learning how to use the camera, go with a point-and-shoot camera. Something without too many features. If you are a camera enthusiast who wants to do more with your camera or is willing to take the time to learn how to use the feature then, by all means go all out.

Sources:

http://www.dpreview.com/

http://www.pcphotomag.com/

http://www.letsgodigital.org/en/index.html

http://dpnow.com/

http://digiphoto.org.uk/123di.htm

http://www.dcviews.com/

http://photo.net/

http://cameras.about.com/

http://digital-photo-basics.classes.cnet.com/



Guide to Buying a Digital Camera

Tuesday, August 5th, 2008
digital cameras
Andrew Gates asked:


The digital camera market today offers buyers a large number of choices, with products in widely differing price ranges, sizes and degree of operational complexity. From miniatures the size of a credit card, to fully functional professional SLR (Single Lens reflex) systems, you can buy a digital camera from manufacturers including traditional camera brands such as Canon, Olympus, Nikon, film companies such as Kodak and Fuji, and consumer electronic companies like Sony. Then there are other options that include the mobile phone manufacturers, and webcam suppliers.

The advantages of digital photography are numerous. Topmost is the fact that there is no film processing: expensive both in cost and time. But there is also the advantage of smaller sized equipment, portable media and instant picture viewing. And if you don’t like what you see, you simply delete it and shoot again: no wastage.

If you like to take pictures, being a digital photographer makes a lot of sense. But which camera is the best one for you? In a field of excess abundance, how do you narrow down what you need? How much to pay? How many megapixels? (What are they anyway?) Which brand? How much memory?

Digital CamerasEvery shopper is different.

At MyShopping.com.au we recognise this fact, and so we list practically all brands and models from hundreds of suppliers. These listings include the cold hard digital data facts about each camera and a range of comparative pricings offered by different suppliers. But just as every shopper is different, every photographer is different too. And just having the facts may not make you feel any more knowledgeable about which camera is right for you.

You could begin with the question: What sort of pictures will you take with your new digital camera? This is a valid starting point because from here you can begin to qualify your requirements in terms of technical capability and price. What sort of pictures will you take with your new digital camera?

Is it simply for happy snaps whenever you get together with friends and family at weekends and holidays? Or are you a serious bird watcher and you want to capture nature at its finest? Perhaps you want a camera for work to record your inventory, or recording information from a client. Maybe you’re a PI on a mission. The point is, you need to begin by recognising that your reason for buying a digital camera may not be the same as that of your best friend who is recommending the model she bought.

Once you’ve figured out the sort of pictures you are going to take, you can then set about deciding on the type of camera that will meet your needs. If you need something highly portable that fits in your shirt pocket or your handbag and lets you take it anywhere you go, make size a big consideration. If you want to take seriously good photographs, and you want to pursue an artistic endeavour, make image flexibility your main concern.

It might also be worthwhile considering your own position in the digital photography experience. Are you a novice about to buy your first camera, do you have some intermediate experience, or are you an advanced user?

Someone new to the market will likely not want to spend a lot of money, nor have a lot of mind-boggling features that leave you confused. There are cameras ideal for beginning users that have basic ‘point and shoot’ features including optical and digital zoom lens, flexible storage media and built in flash. There is a huge range of cameras available with simple features at low cost.

If you consider yourself an intermediate user with some operational knowledge of digital camera technology, you may want to consider more advanced features that give you more control over the pictures you take. These features usually come in a range of automatic settings and manual settings for capturing the image and different storage options in terms of resolution and picture type (raw data, jpeg, tiff). Naturally there is some cost attached to additional features when compared to more basic cameras.

For advanced users, there are a lot of professional options you can consider; such as SLR view finding and lens interchange ability. Cameras in this range provide much greater control over the image, both before and once it is captured. These options include shutter speed and aperture adjustment, and many cameras offer the ability to manipulate images ‘in camera’, such as cropping, and brightness and contrast adjustments.

After the picture is taken

A further main consideration is what are you going to do with your images once you have them? The great beauty of digital photography is the simple fact that you can store them on digital media such as CDs and media cards, and view them on computer screens and in many cases, your television. You need print only when and those you want to see, or show to others. Digital photography also gives fantastic opportunities to manipulate your images using popular image manipulation programs, resizing them, altering brightness and contrast characteristics, and correcting problems such as red eye, or removing skin blemishes.

Most digital cameras are computer ready, able to plug directly into your PC or Mac using USB connectors. They usually include proprietary software allowing you to easily and instantly manage your image files in photo albums or slide shows. Many digital cameras also include a video capture facility enabling you to take short motion pictures.

What you want to do with your images after you have them can have an impact on your choice of camera. If you want to make enlarged prints for example, you will want a high megapixel capacity (also talked about as ‘resolution’). If you want images for website use, you will want to get the best quality images that can be reduced in resolution without severe degradation.

Beauty is in the “I”

Great pictures usually come from great conditions. You capture a great moment, the light is just right, the subject is at the perfect distance, the image is perfectly framed. But not every digital camera offers the flexibility to make the best of existing light conditions, or position. Most digital cameras (certainly at the budget end) come with a built in automatic flash, which is terrific for happy snaps in darkened environments. And the automatic flash automatically does not ‘go off’ in bright sunny conditions. But in those times when you want to use the existing light, you need a camera that gives you manual control over the operation or not, of the flash.

Moreover, most digital cameras in the lower and medium price ranges are highly automated. If you are moving from a traditional SLR film camera where you have maximum control over shutter speed, aperture and ISO speeds, it may be frustrating to not have easy access to the same range of tools to take advantage of existing light conditions.

In the more advanced (and therefore more expensive) range of digital cameras, most lens and aperture functions are available in exactly the same way as other SLR systems. What differs is how the colours and light of the image is translated through pixel capture compared to the chemical processing systems.

You may want a wide range of focus options. Most digital cameras have two different types of image magnification, lens magnification (zoom) that may be equivalent of a 35mm to 150 mm lens, and a digital magnification that may be to ten-fold (expressed as x10). This provides you with zoom lens capability, which may be limited in its depth of field control and is subject to soft focus and movement if the conditions aren’t just right, and a digital magnification of the pixel image. If being able to capture magnified distant images is important to you, you need more megapixels, and a lens system that gives you some control over its focus and aperture management.

A final word on accessory

Digital cameras are electronic equipment. That means they run on batteries, and if you use your camera a lot, you will find that you will be frequently replacing batteries. Some cameras have rechargeable batteries; others simply use dry cells (AA), which you can of course load with rechargeable ones. It pays to have spare batteries so that you always have a charged power source. Some cameras have docking stations to help manage the connection with computers. Many digital SLR cameras have interchangeable lens systems, some of which may be compatible with traditional film SLRs.

You can also print your own pictures at home with special printers that handle standard photograph paper, and connect directly to your camera. Although it may be less expensive to simply take your camera’s card, or a CD to your local camera store, and now many supermarkets and department stores, and use the automatic printing machines to print the images you want.

There is a lot you can do with a digital camera, and you can pay les than $200, or more than $10,000. It all depends on how you see yourself as a photographer, what you’re shooting, and what you want to do with your pictures. At Myshopping.com.au you can very quickly compare specifications and prices.



Things you Should Know Before Buying Digital Camera

Sunday, July 20th, 2008
digital cameras
jay smith asked:


If you are looking to buy a digital camera, you should properly educate yourself about all the different aspects of digital cameras. There are many types of digital cameras out there all with different features, so you should first ask yourself a few questions before actually spending several hundred dollars on your big purchase.

1. What exactly are you going to be using the camera for?

2. Will it be used as part of your job or will you use it for recreational purposes?

3. Should you buy a mini digital camera or should you look for a standard size digital camera?

4. How much money are you willing to spend and what is your budget for your digital camera expenses?

Remember, the camera itself is just one part of the cost; you still need to pay for batteries, computer cables, and memory and media types for storing your pictures and video.

Some other things you should keep in mind when trying to select a suitable digital camera are the weight of the camera and the look and feel of the digital camera. If you need to take the digital camera with you during your daily routine or job, you should make sure that it will not get in the way of whatever it is that you need to do. Another important aspect of digital cameras that you should be aware of is the zoom function.

There are two basic types of zoom, optical zoom and digital zoom. Optical zoom is the type of zoom where you press a button and the lens physically moves around in order to zoom in or out. This is the zoom method that you are probably the most familiar with. The other type of zoom is known as digital zoom.

Digital zoom is a new method of zoom that has been introduced with the invention of digital cameras and does not rely on any moving parts. It basically crops the photo you take and then enlarges it, which in effect creates a type of optical zoom effect. Generally speaking, you should try to use optical zoom over digital zoom, since digital zoom reduces picture quality by a great deal in most cases.

If the reason that you want to buy a digital camera is for recreational purposes only, you should consider the option of buying a mini digital camera. Generally speaking, mini digital cameras are not as powerful as your standard size cameras, but they have several advantages. Obviously, they are portable and very convenient to bring along with you on your travels. Most mini digital cameras will fit in your pocket without a problem, whereas standard size digital cameras can be quite bulky and awkward to carry around at times.

Another benefit of having a mini digital camera is the fact that they are great to show off to your friends and family. They make great conversation starters and if anyone sees you taking a picture with a tiny digital camera, odds are that they will stop to chat with you a bit about the price and specifications of your camera. Finally, mini digital camera accessories are a bit cheaper than standard sized accessories so you can expect so save a bit of money when buying your accessories.



Digital Cameras – the Constant Innovation and What to Look for When Buying

Wednesday, May 21st, 2008
digital cameras
Boris C. asked:


Main Concept And Evolution

When digital cameras became common, a question many photographers asked was whether their film cameras could be converted to digital. The first recorded attempt at building a digital camera was by Steven Sasson, an engineer at Eastman Kodak. The first true digital camera that recorded images as a computerized file was likely the Fuji DS-1P of 1988, which recorded to a 16 MB internal memory card that used a battery to keep the data in memory.

Digital cameras can include features that are not found in film cameras, such as:

- Displaying an image on the camera’s screen immediately after it is recorded.

- The capacity to take thousands of images on a single small memory device.

- The ability to record video with sound.

- The ability to edit images and deletion of images allowing re-use of the storage they occupied.

A digital camera is a camera that takes video or still photographs, or both, digitally by recording images on a light-sensitive sensor. Most digital cameras measure subject distance automatically using acoustic or electronic techniques, but it is not customary to say that they have a rangefinder. The resolution of a digital camera is often limited by the camera sensor (typically a CCD or CMOS sensor chip) that turns light into discrete signals, replacing the job of film in traditional photography.

Digital cameras have high power requirements, and over time have become increasingly smaller in size, which has resulted in an ongoing need to develop a battery small enough to fit in the camera and yet able to power it for a reasonable length of time. Digital cameras are incorporated into many devices ranging from PDAs and mobile phones (called camera phones) to vehicles and even webcams. Webcams are digital cameras attached to computers, used for video conferencing or other purposes.

When You Buy Digital Camera

Measuring the “pixels per dollar” as a basic measure of value for a digital camera, there has been a continuous and steady increase in the number of pixels each dollar buys in a new camera consistent with the principles of Moore’s Law. Before you buy digital camera, it is important to determine what kind of pictures you want to take with it. Be sure to check first its capacity to produce high quality photo images and don’t forget about camera’s batteries – make sure they are rechargeable.

When you buy digital camera, sometimes the spending does not end there. For instance you may want to buy additional memory if the one that is already included doesn’t suit your need and its capacity is not enough for you. This is why you must make sure that the gadget that you buy has not only a “built-in” memory or a card slot for external and additional memory, but also includes memory card with good enough capacity.

The LCD is a special consideration you have to look into when you buy a digital camera. This is a small screen located at the back of a digital camera that allows you to preview the pictures you took. This has to be considered when you buy digital camera, because it uses up a lot of battery power.

It is essential for you to feel comfortable holding your digital camera while shooting. So, before you buy digital camera, the right thing will be to test and check if you are comfortable holding it and using it. Special features that will suit your needs should be thought about, too before you buy digital camera. No matter what your needs and wants are for the device, your financial resource will play a huge part in dictating the type of digital camera you will buy. When buying digital camera in online store, make sure you already know what you want and start sorting by lowest price first and later calculating shipping and sales tax.

With these information, you can now figure out what you really need and want before you buy digital camera.