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.

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.

There is no debate that digital cameras are going to take over the photography market and with time we will see less and less film cameras sold and used. It is beneficial to take a moment and try to list the advantages of digital cameras and digital photos and put some order in why everybody likes them so much. In this article you will find that list.

Digital photos and digital cameras have many advantages and allow many new usages that were not possible with film. Here are a few:

Low photo cost: Photos taken with a digital camera literally cost nothing. The photos are kept in erasable memory and thus can always be discarded at no cost. Viewing the photos is immediate and does not cost anything (there is no film development cost). Also the photos you would like to keep can be copied to digital media such as a computer’s hard disk. With storage prices going down the cost of saving a photo on disk is practically zero.

The capacity: With ever growing storage capacities digital cameras today can hold hundreds and sometimes thousands of photos on a single media. You can always have a few more in your pocket and changing is very fast. The result is that a digital camera has practically infinite capacity. You can shoot as many photos as you want and at the end of the day just dump them on your computer’s disk. There is no time lost changing film and there is no photo opportunities lost due to lack of film or reserving film for later.

The feedback: One of the great advantages of digital cameras is instant feedback. Almost all digital cameras include a small LCD screen. Once a photo is shot you can go back and watch it on that screen. The ability to see how the photo looks like results in better photos. If the photo is not good you can take another one. Being able to see the photos on the spot results in an educated decision how to fix a photo or how to compose it better. It takes a lot of the guessing away from photography.

New shooting angles: With digital cameras you can take photos without your eye glued to the viewfinder. Overhead shots where you raise the camera over your head are much easier since you can still see what the camera is shooting by just looking up at its LCD screen. You are not limited anymore to angles where you can look through the viewfinder - you can shoot from any angle that the LCD is visible from. You can always shoot blindly like photographers used to do with film cameras.

Correcting photos: With digital cameras photos can be corrected using photo editing software. Some correction abilities are built-in the cameras but many more are available as software packages for your PC. Such corrections include red eye removal, contrast enhancements and more.

Changing conditions: With digital cameras the settings of the sensor can be changed instantly for each photo taken. With a click of a button the camera can be put in an indoor or outdoor mode, low light, night photography etc. Some cameras will automatically sense the scenario and set the sensor mode accordingly. This is literally like changing a roll of film to the optimized one for every photo you shoot - the best ISO, color features and more.

The purpose of using a tripod for digital photos is to reduce the chances of blurring the pictures. Even if for most parts, the image is clear, because of the slightest camera movement, the entire picture could be ruined. That’s why you will always see a tripod or monopod in a professional photographer’s camera bag! A camera tripod is extremely useful when taking pictures in dim light. When there isn’t enough light, the shutters are slower, therefore, increasing the chances of the digital image blurring out. A tripod can easily solve this problem. A tripod is also useful when you are planning to make large digital prints of the photos - a good support from a digital camera tripod will make a world of difference.

Well, even if you don’t have a tripod handy, you can always use someone else’s shoulder for support - just so your digital camera won’t shake as much when you take the shot. Well, in any case, it’s always better to use a tripod if there was a choice.

We see new models and types of digital cameras every single week, and the same thing can be said about tripods. The materials used to make digital camera tripods continue to change - the familiar aluminum tripod is now replaced with the lighter and more expensive carbon fiber tripod models. Although there’s quite a huge shift in pricing, some photographers think that investing in a lighter and more durable model of tripod is worth it - especially if they’re in the game for the money!

Before you buy a tripod for your digital camera, the first thing you must consider is how you plan to use the camera. There are essentially three heights that you can choose frommaximum, minimum and collapsed. It depends on the kind of tripod you like. The maximum tripod can be a little bit unstable as with everything tall and lanky. The minimum tripod can be a slightly inflexible, but is especially useful when taking low shots and trying adjust the lens to eye level. The collapsible is the most preferred type of tripod.

In professional photography, a tripod can help you take low shots on objects from the top. This can be done when you place the object on the floor and arrange the tripod on top of or slightly over the object, and then take a shot. Most of the high quality tripods come with a center column that enables you to adjust the height of the tripod according to your needs. Take your time and adjust the tripod height accordingly. To find the right angle, make adjustments to the tripod head.

With a tripod, you can easily take professional photographs even if you’ve never taken a professional photograph all your life! That’s how big a difference a tripod can make.

Dakota Caudilla, journalist, and website builder Dakota Caudilla lives in Texas. He is the owner and co-editor of http://www.tripods-and-more.info on which you will find a longer, more detailed version of this article.