Digital Camera

In many digital still cameras, the image sensor capturing our photograph in place of the standard film is a CCD (charge-coupled device). How it is manufactured and what happens in it when we press the shutter release button is of interest to any good photographer, because it may contribute in taking better photos. Moreover, basics of lingo are useful for the understanding of characteristics of a camera, especially if you are going to buy one.

A pixel element of a CCD, in its simplest form, is basically a MOS capacitor, i.e. a semiconductor structure made of three layers: Metal-Oxide-Semiconductor. The semiconductor part of the MOS is simply silicon while the oxide is silicon dioxide, acting as an insulating layer. The metal is not a real metal substance, but rather a heavily doped polysilicon layer and is named “gate“. Basically, the image is formed within the semiconductor part of the MOS system and the metal gate is used for shifting such image.

When we press the shutter release button on our camera, light starts hitting the silicon in the MOS structure, and hole-electron pairs are created via the photoelectric effect. While the holes are drained by the grounded substrate and not utilized, electrons are collected in the semiconductor part of the MOS. We are interested in these electrons, because they will build up our photograph. The region where electrons are collected is referred to as the “channel” and, of course, corresponds to the electron lowest potential energy. In order to get better images, basically all CCD manufacturers use the so called “buried channel structure“, where the electrons are collected not at the oxide-semiconductor interface, but a little bit distant, within the semiconductor (hence the name “buried”). In order to confine the photo-generated electrons in the channel, “channel stops” are created in the MOS structure, isolating each MOS element from the adjacent ones.

The number of photoelectrons collected is linearly proportional to the intensity of the photon flux and to the time this flux hits the pixel (”integration time“). Consequently, we now know that the brighter the registered scene, the greater the number of electrons. The efficiency with which incident photons are detected is known as “quantum efficiency“; a typical value is 40%. This value is pretty low because of the absorption caused by the passivation (protection) layer present on the integrated circuit and the presence of the polysilicon gate that must be passed through by the incoming photon.

A single pixel of our digital camera is made up of a structure similar to the MOS capacitor outlined above. It’s a little more complicated, though, because we don’t want electrons to be confined where they are generated forever, but want to sense how many electrons have been generated. In order to accomplish this, each CCD pixel is made up of 3 parallel gates (although variations are possible) and, perpendicularly to these, a channel stop on both sides. By keeping the central electrode (gate) at a higher potential than the other two, electrons will be attracted there and so collected. The CCD is then made up of a matrix of millions of these pixels, arranged in thousands of rows and thousands of columns.

So, upon pressing the shutter release we start the acquisition phase, and this ends after the exposure time set by the photographer (typically 1/2000s to a few seconds). At this point we must read the number of electrons collected in each pixel. The greater the number of electrons, the brighter the pixel. For this purpose, a charge transfer process must take place from each pixel to a sensing circuitry. To achieve this, a shift phase occurs, exploiting the 3 gate structure described above, after which the electrons of the first row are shifted into an array of serial registers located at the edge of the CCD matrix, the second row electrons are shifted to the first row and so on. The efficiency with which the transfer process occurs is measured by a parameter called “Charge Transfer Efficiency“, a typical value of which is 99.999% per pixel. The serial register shifts its content into a charge detection output amplifier one pixel at a time. The output amplifier converts the electrons’ charge to a voltage. The order of magnitude is an output voltage of about 1 microvolt per electron and this is a linear relationship. The slope of this curve is referred to as the “output sensitivity” or “conversion gain“. The higher the voltage, the brighter the pixel. Once all the pixels of the first row are read by the output amplifier, the shifting phase takes place again and the whole sensing process is repeated. This is so until all the pixels in the matrix are read out.

This is the end. Nothing else happens in the CCD chip. All the rest of the image processing is done off-chip. In particular the voltage read out by the CCD is first amplified and then converted into a digital value by an off-chip analog to digital converter.

Andrea Ghilardelli runs an online photo retouching service. To get your pictures beautifully retouched and for articles about photography, please visit his site: www.ilghila.com.

One of the oldest companies, Olympus has had a long and historical journey. Olympus digital cameras are being used all over the world today. Let us take a look at the glorious history of Olympus here.

Olympus was started way back in the year 1919 under the name of Takachiho Seisakusho. In fact, the first optical product made by the company was not a camera, but a microscope! The name ‘Olympus’ was introduced in 1921 as a trade name for the company’s optical products.

There is an interesting story attached to the name of Olympus. It has a deep, deep meaning attached to it as well. According to Greek mythology, Olympus is the mountain where the Gods live. And, Takachiho is the mountain where the Gods live according to the Japanese texts. In fact, all the names associated with Olympus cameras have a hidden meaning to themselves. For example, the first product made by Olympus for photographic purposes was the Zuiko 75mm/F4.5 lens in 1936. This is an abbreviation coined from the name of Olympus optical plant (Mizuho Kogaku-kenkyujo) and also has a hidden Chinese meaning.

In the ’30s, Olympus introduced many different types of cameras. Due to the world wars, production suffered from time to time till the ’40s. The Twins Reflex camera was introduced in 1950s and became instantly popular. In fact, hundreds of models based on this technology were developed by several manufacturers. But it was the Olympus Rolleiflex which set the standard for these cameras in the industry.

However, it was the Olympus PEN which was launched in 1959-60, which established Olympus as the manufacturer of small cameras in the market. The PEN was light, small, innovatively designed and could take 72 shots in one roll! It became increasingly popular and helped Olympus to gain hold of the market. After this, there was no looking back for Olympus and it went from strength to strength.

As far as digital cameras are concerned, by the 80’s and ’90s, the video camera and the consumer digital cameras were already present in the market. However, they were not of very high quality and could only used for web publishing or low-res prints. But, by the late ’90s, technology had advanced greatly and prices had also dropped, hence consumers were now going in for digital cameras more and more. It was at this time, in the year 1996, that Olympus introduced its P&S style cameras which had a resolution of 810.000 pixels. Slowly and steadily, Olympus came up with a 2 mega pixel and then a 3 mega pixel camera by the year 2000. At this time, one of the significant launches of Olympus was the 2.11 mega pixel model C-211 which also had an in-built Polaroid printer.

Today, Olympus is considered to be one of the well-known digital camera manufacturers in the industry. The latest digital cameras by Olympus are:

D-Series: Simple point-and-shoot cameras for beginners.

C-Series: Digital cameras for advanced photographers.

Stylus: Stylish cameras in attractive colors and designs.

E-System Digital SLR’s: Professional SLR’s for digital cameras.

Kevin Rockwell worked as a network TV cameraman for 20 years shooting news and sports. Now a devoted fan of digital photography and video he works to gather information, tips and news for digital camera users. Oh and he loves to shoot pictures of his kids playing sports.
http://great-digital-cameras.com/gdcj.html

You need batteries to power your digital camera otherwise you won’t be able to use it. Most digital cameras use
the standard-sized AA batteries which are reasonably priced and easily available anywhere. However, you must
invest in rechargeable batteries as digital cameras tend to use a lot of power and you might find that your
batteries are dead after a few shots. A lot of people especially when they are sightseeing tend to leave their
cameras on. This, too tends to drain the battery.

There are different kinds of batteries available for digital cameras today. The regular alkaline batteries are all right
to use in an emergency but not on a regular basis. They just don’t have the power to last for more than a couple of shots. When they are recharged, the power you get from them is even less. Digital cameras need batteries that
can cope with the high amounts of energy they need, especially when you use the flash.

The most popular batteries for digital cameras are the rechargeable NiMH or Nickel Metal Hydride batteries. They
don’t cost much and are definitely better than the standard ones you get. They could give you up to one hundred
shots if you are careful with how you use your camera, switching it off when you don’t need it. Of course, if you are into more than just the aim-and-click photos, you must be prepared for the charge going fast, especially if you use the flash or you adjust the focus and zoom a lot. Yet another advantage is that these are environment-friendly as they are non-toxic.

When it comes to charging these batteries, make sure you have a good, reliable charger.
Remember that batteries can get overcharged so look out for one that has an automatic switching-off when the
batteries are fully charged. Always charge all the batteries your camera needs to be powered at one go - whether
two or three or four. This way, they are all equally charged when you put them in.

Some digital cameras have to use lithium-ion batteries. The advantage of these, though they are more expensive, is that you can store them and they don’t lose their charge. You can use them for twice as long as the NiMH
batteries. Most manufacturers give you a lithium-ion charger when you buy your camera. If they don’t, just make sure you buy one as then they come as accessories.

You digital camera is only as good as the shots you get. If you chance upon a one-in-a-million view and your batteries are dead, it’s a waste of a view and the waste of a camera. Your batteries, no matter how good, are only good if they are well-charged. So invest in a good battery charger. One in which you can control the time of charging so your batteries don’t get overcharged. Once you have your batteries and charger in place, the world is yours, literally, through your viewfinder!

For more information on Batteries for Digital Cameras or the Advantages of Digital Photography visit http://www.Digital-Photography-Help.com

Night photographs express a special something that cannot be seen in normal daytime photography. Whether it is a photograph of a moon and starlit sky over a windy deserted beach, the excitement of a downtown cityscape when the lights go on, or just a picture of you and some friends in front of a favorite hangout, nighttime photos, when done right, are sure to attract attention.

However, even for experienced photographers, nighttime photography can be a tricky situation. Photos often look unfocused, blurry, or lacking crucial details, and many may not come out at all. There are some tricks, though, to taking spectacular nighttime photos with your digital camera, tricks that can be explained yet only completely learned through practice.

This first part of a three-part series on nighttime photography will cover tricks not necessarily related to digital camera settings, but tricks nonetheless that can result in better photographs or a more pleasing photo-taking experience.

* Although more expensive digital cameras do not necessarily result in better photos, realize that the cheapest cameras may not be capable of taking great photographs at night. It requires more work, both on your’s and the camera’s part, to take spectacular shots in very low-light situations. Though you don’t have to spend over a thousand dollars for night photography, don’t expect too much out of a sub-two hundred-dollar camera, either.

* Especially if you are not completely familiar with your camera’s settings to enhance nighttime photography, consider first taking some photographs around dusk, when the sun has not yet completely left the sky. Dusk photos can sometimes be even more dramatic than those taken in the pitch-black sky, as the added light helps illuminate details easily missed in a completely dark environment Check your local newspaper where you are shooting photographs or a website such as http://www.weather.com for sunrise/sunset times, and be ready to shoot around a 20-30 minute window for best results.

* Plan your photos before you shoot! While it is always a good idea to study an area first, this is crucial if you are planning on snapping photographs around dusk! You will not have much time to plan, and if you spend five or ten minutes just getting a perfect angle or framing the perfect shot, the overall lighting will change as the sun slowly sets. And of course, remember when composing your photos that the sun sets in the west.

* Be prepared for the environment. If you’re heading out by yourself, especially in a semi-deserted wilderness area, always carry a map so you remember how to get to your home, camp, or hotel. Check the weather before you go and wear a poncho or coat if necessary. Carry a flashlight, or, in the most extreme environments, a flare, to help others find you if you become lost. Also, bring along a WELL-CHARGED cell phone in case of emergency! You’re taking photos at night to have fun and create spectacular results. Be prepared for unexpected situations so they don’t ruin your experience.

While the results can be outstanding, night photography presents its own unique benefits and hazards. Not just any digital camera will do; lower-end models may not have the capability of taking spectacular shots. Timing is crucial, especially when taking pictures in the brief time between dusk and total darkness. And, the environment and weather can play havoc with your plans. By purchasing the correct equipment, studying the subject area before nighttime falls, and dealing with unexpected situations with the correct nighttime gear, you can be better prepared to take amazing nighttime photos.

Copyright 2004 Andrew Malek.

Andrew Malek is the owner of the MalekTips computer and technology help site at http://www.malektips.com. Visit his digital camera page at http://malektips.com/digital_cameras_help_and_tips.html for more digital photography advice.

A digital camera can appear complicated, but there are certain basic points that can be quickly learned and will help you become a better photographer. It is worth it to spend some time thinking about your camera’s pixel count, white balance, sensor, sensitivity, optical zoom, digital zoom, etc. These features will improve your pictures and increase the enjoyment you get from your digital camera.

A digital camera’s basic unit of measurement is its number of pixels. The clarity and resolution of your pictures improve with the number of pixels per square inch your camera has. Each pixel contains within it three color channels (red, green and blue) and carries a numerical value of between 0 and 255.

Digital camera manufacturers use the pixel count as one way to describe their product. The pixel count of low-end digital cameras are usually around 1 million, a number that seems large, but is strictly for beginners! Better digital cameras and those used by professionals range in the 14 million to 22 million pixels-per-image.

Pixel number also determines the quality of your pictures at a given size. For example, a 3MP camera can give you beautiful 4″x6″ prints, but would not give you the same quality at 5″x7″ or larger. A 4 or 5 MP digital camera is necessary for excellent quality bigger prints.

You should also be familiar with your digital camera’s digital sensor. The sensor element in most digital cameras is small, about the size of a fingernail, which is much smaller than a 35mm camera’s negative. Again, high-end cameras have the larger sensors, which produce better quality large prints.

Another helpful feature of your digital camera is the white balance. This is adjusted to suit the light source and keeps your colors true, ensuring that whites are pure and not yellow or blue looking. Generally, your digital camera adjusts automatically, but for a really beautiful shot, you can manually adjust to get results exactly as you want them.

A digital camera’s sensitivity setting is similar to ISO ratings on film. Generally, the sensitivity settings of digital cameras compare to ISO100 and ISO 200. Some have a setting for ISO 400. A few digital cameras with large sensors (and large price tags) have a setting for ISO 3200 or ISO 6400.

Another very important feature to be familiar with is optical versus digital zoom. Both are important, but for different reasons. Digital zoom physically crops the image to a smaller size; this cropped image expands to fill the frame. This cool feature allows you to cut out ugly background or focus on a particular object in the frame that might not be centered. Depending on the amount you “zoomed” out, there may a significant loss of quality in your pictures. The optical zoom lens actually changes the magnification and focal length, drawing subjects in and out depending on your desire.

Picture image storage can also be an issue and it’s important to familiarize yourself with the manner in which data is stored. Each pixel generates three bytes of data. A photographer using a modest 3MP will need an amazing nine million bites to store each picture! Compressing an image using a format called JPEG significantly reduces the file size, which causes a corresponding loss of quality. For some purposes, this loss is not important, but as a rule, it is not preferable. Digital camera manufacturers have come up with different storage format designed to minimize this data loss. The format is not uniform; for example, Nikon calls its process NEF, while Canon calls its format RAW.

For more information on the advantages of digital photography please visit Digital-Photo-Tips.info where you will find a digital camera buying guide and helpful information on how a digital camera works.