CCD Edge

CCD-based camera is the imaging tool of choice at professional observatories. Because today’s CCD cameras are affordable, even amateurs can now purchase and use them. In fact, the amateur today, with modest equipment, can routinely image objects which were once photographed only in professional observatories equipped with huge and expensive telescopes.

The CCD camera has enabled the amateur astronomer to capture esthetically-pleasing images of faint galaxies, nebula, star clusters, and other distant celestial objects. More important, amateurs are now making significant scientific contributions with their CCD-based imaging systems. All of this is possible because the CCD detector, which is the core of the CCD camera, has many advantages over other types of light detectors.

The CCD detector has many advantages that give the CCD imager an edge when capturing images of distant, faint astronomical objects. The major advantages of CCD-based cameras are their light gathering efficiency, linear behavior, cooled operation, digital images, and immediate image availability.

The CCD detector is a highly-efficient collector of photons. Quantum efficiency (QE) is the measure of a detector’s efficiency in detecting photons. More specifically, QE is the percentage of photons that are converted into a usable signal. Whereas the naked eye and emulsion film have a QE of about 1%, today’s CCD detectors have a QE of 50-85% in the visible spectrum and have a much broader spectral response than other digital or video cameras. The CCD detector’s high QE makes it possible to image an object with shorter exposures than required when using a film camera. There is less time for problems with the imaging system to degrade the final image if shorter exposures are used.

The linear characteristic of the CCD detector makes it the tool of choice for scientific imaging. The signal collected is proportional to the luminosity of the imaged objects. For scientific research, this predictability is important. For example, linearity is critical to the science of photometry. Photometry is the science of determining an object’s brightness. The CCD camera is widely used by both professionals and amateurs for photometry. In fact, the availability and affordability of today’s CCD cameras have enabled amateurs, with modest equipment, to do serious scientific research and to make their own discoveries. The linear characteristic of the CCD detector also makes it possible to remove much of the image noise.

Modern, cooled, CCD cameras do more than make it possible to remove noise. Their cooled operation directly reduces a major contributor to noise: thermal electrons. Cooling the CCD detector makes it possible to take longer images before the pixels become saturated. When CCD pixels become saturated, the excess electrons can spill into adjacent pixels causing extended bright spots in the image. This is called blooming. Cooling the detector helps to eliminate this problem by reducing the accumulation of thermal electrons. Since digital and video cameras are not cooled, noise caused by thermal electrons can seriously compromise image quality as the exposure time increases. They are not, therefore, as desirable for imaging faint objects as is the cooled CCD camera.

We live in the digital age, and the CCD camera is a tool for the times. Coupled with a personal computer, the CCD camera is a natural for astronomical imaging. Because the CCD camera produces a digital image, the images are immediately available for display, processing, or analysis. If the image is not of the desired quality, another can be taken at once. Moreover, feedback from short images can aid the imager in finding, framing, and focusing astronomical objects. In view of all of the advantages of the CCD detector and of the CCD-based camera, it is no surprise that the CCD camera has revolutionized imaging the sky. Both professional and amateur astronomers now use this tool at their telescopes. For the amateur, obtaining images of faint and distant objects–without the use of huge and expensive telescopes–is now possible. Discoveries of new objects, such as supernova, comets, and asteroids are not unusual among amateur astronomers, thanks to the CCD camera. Sky & Telescope and Astronomy routinely publish spectacular CCD images that would not have been possible a few years ago. The CCD-based camera is not only the professional’s edge; it’s the amateur’s edge, too.

Wonders Of Winter

For many of us, the greatest joy in photography is to travel to far-away lands, seeking idyllic locations, that we can only dream about, and then do our very best to capture them. But do we need to travel to capture perfect sights? All around us are places of beauty waiting to be captured and we pass them every day.

We don’t need to go to great expense or travel thousands of miles; dramatic places are found in every corner of every land. But then I do have one of the world’s best locations on my doorstep: the west coast of Ireland.

While the wet weather can keep me indoors for weeks on end, the winter months bring harsh, but inspiring light, where a rugged Irish Landscape thrives.

No more so than a scenic National Park, five miles outside Killarney town, on the west coast of Ireland. Killarney National Park, filled with towering hills and romantic lakes, still remains one of Irelands most unspoiled treasures.

It’s one of those places where my senses come alive; its varied landscape and rugged, yet accessible, mountain range, is a favourite spot with many and a place where I like to spend a lot of time. Its shapely mountain peaks make it a perfect spot to photograph, especially during the cold and icy winter months.

All we need in photography is a different approach. Each season brings its own elements, and winter is no exception. Using our photography skills at the correct time of day can vastly improve our pictures. If you are serious about photography, dawn is the time to be up and about. At this hour, the colours of the sky cast a brilliant orange-red hue that will add mood and character to any setting.

There are also other elements which make winter special. An early morning ramble through the woods can be a perfect start to any day. Our forests are full of great photo opportunities, and an early stroll around deserted woodland can be a remarkable experience.

Rivers and valleys are also prime locations for early morning snaps. If a damp day is followed by a cold night there may be some low-lying mist hanging around. Mist or no mist, an early start works best.

Last light of the day is also an excellent time to be out and about. The evening sun can explode a variety of colours across the sky as it sets for the day. If the sun shines at the beginning or the end of the day, the colour of the light will be much warmer, and will lead to a much more dramatic scene.

So as winter looms, I gather my belongings and head west to capture the mood of the harsh Irish winter, and start the quest for new seasonal images. It certainly isn’t time to put away the camera. Winter brings plenty of great photo opportunities, tougher conditions to work in, but just as satisfactory as any other season.

Art Of Backlighting

There is much to consider when using this technique if frustration and disappointment are to be avoided. However, once mastered there is little doubt that backlighting can be magical and will add both drama and visual impact to your photographs and diversity and interest to your portfolio. There are many subjects to try, my favourites are translucent flowers and foliage or rim lighting of animals and birds. Backlighting will enhance mist, rain and haze adding creativity and atmosphere to landscape images.

The two most challenging aspects of photographing backlit subjects are to adequately eliminate flare and ensure correct exposure. These concerns can be allayed with a little practice, good technique and an understanding of the exposure process.

Flare gives rise to a loss of definition and is probably the most significant area requiring attention, so a measured and methodical approach is needed. It is produced when intense rays of light hit the front element of the lens causing excessive lens refraction, this leads to specula highlights, image softening and loss of definition. Clearly this is to be avoided and there are several ways to overcome this undesirable effect.

Lenses show individual characteristics but in general the more lens elements used in their construction the more vulnerable they will be to flare. With this in mind zoom lenses are more likely to be flare susceptible that prime fixed focal length lenses. Lens coatings also have an impact on flare, modern multi coated lenses consistently outperform earlier models and this alone can significantly reduce most potential flare problems.

In many backlighting situations using a designated lens hood will greatly improve the chances of eliminating flare by keeping stray light from striking the front element of the lens. Indeed, the use of a good quality lens hood can improve saturation in all images.

Having taken the above precautions a final visual inspection of the image through the viewfinder, preferably with the lens stopped down, will show any remaining areas of softness or highlights resulting from flare. This may only require a slight repositioning of the camera to eliminate.

The other challenge in photographing backlit subjects is how best to handle exposure. Overexposure is a common problem in backlighting, as the brightly-lit background will overly influence the camera’s meter; this will turn the subject very dark, indeed almost silhouette like.

Exposure compensation is the answer and it is best to give between one and two stops extra exposure from the ‘normal’ exposure suggested by the camera. Alternatively, take a spot meter reading from the shadow area and expose at the camera’s reading this should require no compensation. As exposure for backlit subjects is tricky it is best to practice various exposure metering patterns and overrides until you are comfortable in approaching various back lighting opportunities that present themselves.

Setting Up Group Portraits

There are some general ‘rules’ of group portraiture that have been around since Rembrandt. Never line up the faces vertically or horizontally. The reason for this rule is that curves, triangles and diagonals create a more dynamic flow and are more pleasing to the eye.. Straight lines are static and tend to line up with the edges of the picture. Another rule is never to have faces look straight into the camera for if they do, unsymmetrical features are more easily apparent and the eyes take on a stare. Now, rules were meant to be broken, but first you have to know the rules.

While couples can be considered a group, I will start with a group of three. The easiest of numbers, three people make an automatic triangle. Heads can be placed in an uneven triangle, foundation side down. Spacing should be varied, but similar in distance. Other successful patterns are the inverted curve with the middle person highest, a diminishing, flatter curve with the smallest person nearest the camera, and a stacked triangle in a vertical format. Groups of three generally look more together when the outside persons face in to the center. Enough body should be included in the composition so an not to appear bodiless. A general rule is to leave twice as much space above the heads as below the feet or hands in the picture. Spacing between heads are measured from the center of the eyes, not the edge of the head. Please do not crop off at the wrists and ankles.

Hands play an important part in the language of the portrait. To look graceful and slender, hands should present their edges to the camera. Oppositely, to appear strong, the backs of hands should face the lens. Never allow the arms to hang down vertically, but find something for the hands to do so the arms are bent at the elbow. Arm rests, furniture and other people are handy tools for creating a dynamic angle for the arms.

Shoulders look best when placed at a slight angle to the camera. Views across the back play up the curve of the spine and the jut of the jaw instead of the breadth of the shoulders. Too much of an angle will make the near shoulder appear too large, due to foreshortening.

Groups of four present an interesting challenge. You don’t want to place one head in each corner, making a square. People are basically made up of curves, not straight lines and appear mechanical and lifeless in this configuration. So what can you do with four people? An inverted curve can be formed with the two highest people in the middle. Make sure one is higher than his neighbor. For a more compact composition, overlap the shoulders, fitting them together like a jigsaw puzzle. This places the heads closer together without dead, empty spaces in between shoulders. Remember to turn the outside faces toward the center for a cohesive look. Other shapes that fit the quad portrait are an off center vertical diamond or rhomboid, a staggered vertical or horizontal zigzag line and an inverted curve of three with the smallest below in the center. Be aware that vertical faces should never be in line.

Five is an interesting and easy number to pose. Spacing becomes more important, informing the viewer of the warm relationship between family members. Basically, the faces place themselves in two triangles, the lower middle person sharing the triangles. A vertical composition stretches the space vertically and compresses the spaces horizontally. Six faces can be grouped as two uneven triangles, one slightly higher than the other. The classic oil paintings of large groups of people contain masterful examples of group posing.

Environmental settings play an important part in the balance of a portrait, creating a foil of shapes against the more important faces. If there are masses of light areas, they must be balanced with the appropriate mass of darker areas elsewhere in the picture. The eye travels an omega curve, starting in the lower left corner and wandering through the centers of interest (faces) until exiting out the lower right corner. The centers of interest should fall along this comfortable line.

Aerial Photography

Aerial photography will always be a form of photography that most people aspire to doing one day in their careers as the photos photographers are able to create can be magnificent when done correctly. There is a myriad of settings all over the world that would look great from the air and many photographers are beginning to take advantage of these opportunities.

In fact aerial photography is actually a stream of landscape photography and you can see why. From the air the most impressive photos are taken of vast landscapes, perhaps of mountains and deserts. One of the most popular places in the world for aerial photography nowadays in in the steep slopes of the Himalayas. Parasailing has become a well known hobby in this part of the world and along with it people are capturing some spectacular photos of amazing scenery mostly of the enormous Himalayan mountains in Nepal and Tibet.

Some Fields where Aerial Photography is Important

Of course aerial photography is not just a hobby for many people and organizations. The military use aerial photography for a more important reason. These days many countries use spy planes to take photographs of enemy units on the ground. It’s an important piece of the military and in many cases has meant the difference when the time has come to send troops in to battle.

Television stations use aerial photography as a means of discovering what the weather is like in certain areas and even to predict what the weather is going to be like in several days.

Aerial photography is also used by real estate development companies in order to take photographs from the air of certain developmental sites. This is very important because it enables them to map out and plan how they are going to develop in a certain area.

The same goes for construction companies who need to make sure the position they are building in is going to be safe and of the right width and diameters.

The tourism industry likes aerial pictures because it can show off its vast golf courses, resort beaches, RV parks and campgrounds from above.

City and state governments can use it for planning and development purposes.

Trained environmentalists use aerial photography to study the earth’s climate and land conditions.

Sports events can employ the use of aerial photography when they want to show the grandeur of a brand new stadium or illustrate the density of the crowds in the stands.

Optimize Photos for Web

  • Always have a back up original format copy of your image. Never alter the original. Believe me you will regret it.
  • Crop to size. Make sure that you crop out any extra information that isn’t needed. Remember the larger the photo the longer it takes to load or send.
  • Resize to reduce pixels. There should be an option to resize according to pixels. You’re going to want the largest size to be no more than 250 pixels or you can reduce the dpi to no more than 96.
  • Reduce the color palette. Many images have millions of colors so the first thing that you need to do is reduce the colors to 256. You will lose some depth with this.
  • Save the file in a standard format. JPEG is the most common for photos and you can compress the image with a JPEG for further reduction in file size. It’s not unusual to see GIF or PNG as well.

Remember that with a 56k connection a 150k file will take 20 seconds to load. If you’re creating a web page every photo that you add will add to the time it takes to download all of the images. If you keep the images small in size the smaller resolution will not be as obvious.

File Format for Every Occasion

PSD

If you use Photoshop for your digital photo editing then PSD is probably the most important file format that you need to know. A PSD file is a Photoshop file format and is your best option when working on digital photos for two main reasons. First of all, PSD files allow the user to work in layers and channels and save work being done without compressing the layers. This of course usually results in a large file size. Secondly, PSD files do not lose image quality as you work on images because there is no compression when the file is saved resulting in lost data. It is always best to save your work as a PSD file until your image is finished and then you can save into the format most appropriate for your project.

JPEG

JPEG, which stands for Joint Photographic Experts Group, is one of the most common and well known file formats. JPEG files are good for web use as well as a variety of applications due to their small file size. Due to compression JPEG images loss data (image quality) each time change the file is saved.

GIF

GIF, or Graphics Interchange Format, is a popular file format for web use and other Internet applications. These files are typically small in size and load quickly in Internet browsers. GIF files are limited to a maximum of 256 colors.

TIFF

TIFF, or Tagged Image File Format, are high quality images but are not really used that often and are not good for Internet use.

Although there are more file formats than we have listed here these are the formats you will want to use in your Photoshop photo editing projects. For the most part, the only formats you will use on a regular basis are PSD, JPEG, and GIF.

e-Photo Albums

It is about time we face it. Although the original idea of pressing some buttons to produce a clear copy of the digital images stored in a computer’s memory seemed extremely hassle-free at the beginning, the truth is that the more you use your digital picture the more digital pictures stay in that computer’s memory for a long time. But storing them in a hard drive at home or online, does not permit everyone that wishes to view them to be able to do so, since not everyone knows how to log on to the Internet, if in fact an internet connection is available, or how to view and download their photograph copies from your choice of online image hosting server.

As a result, more and more people have decided today to return to using more old-fashioned ways in order to present their choice of digital photographs to their beloved ones. Creating an electronically made photo-album and then sending its hard copy to the homes of family members and friends, constitutes a lovely and thoughtful action. In fact, by creating a variety of photographically embellished products, communicating feelings and thoughts is easily done and much less time-consuming. Interested individuals are able to upload their digital images to some of these online image servers (image banks) and then select and create their choice of personalized mug, book cover, bag, t-shirt, and of course, photo-album. Reliving the excitement one once felt, when the local photographer called to inform that the prints outs of that trip’s pictures were finally ready, seems today to excite a great number of technology enthusiasts. With the ready-to-use image software of websites like Shutterfly, Photoworks, and Kodak EasyShare, producing a personalized photo-album version can be a fun as well as an instructive experience.

So, get started by selecting your theme and photo-album design template. Choose colors, textures and captions if you wish and send your lovely grandma her much-deserved copy of photographs. You better hurry up as time is ticking and you will soon be picking up the phone trying to figure out how to answer those “you’ve-forgotten-all-about-me” arguments.

White Balance Explained

If your camera’s white balance is set incorrectly, or if your camera chose the wrong algorithm for measuring colour temperature, then you will observe a colour cast on your image: it will either look slightly blue, slightly orange, or slightly green. A low colour temperature shifts light toward the red; a high colour temperature shifts light toward the blue. Different light sources emit light at different colour temperatures, and thus the colour cast. Let’s take a look.

Colour temperature is effectively the warmth that is emitted from a light source, and the effect that temperature has on the intensity of any particular colour in the visible spectrum. For example, a 200 W bulb has more intensity in the orange/red end, and shows purples and blues with very little intensity. This makes your photo appear “warm”. Daylight has equivalent intensity across the whole spectrum, so you see purples and blues with the same intensity as oranges and reds. But shade or a heavily overcast sky has more intensity in the blue/purple end, so your oranges and reds will have very little intensity. This makes your photo appear “cool”.

Here are some examples of colour temperatures from common light sources:

  • 1500 K: candle light
  • 2800 K: 60 W bulb
  • 3200 K: sunrise and sunset (will be affected by smog)
  • 3400 K: tungsten lamp (ordinary household bulb)
  • 4000-5000 K: cool white fluorescent bulbs
  • 5200 K: bright midday sun
  • 5600 K: electronic photo flash.
  • 6500 K: heavily overcast sky
  • 10000-15000 K: deep blue clear sky

Newer light sources, such as fluorescent and other artificial lighting, require further white balance adjustments since they can make your photos appear either green or magenta.

Your camera searches for a reference point in your scene that represents white. It will then calculate all the other colours based on this white point and the known colour spectrum. The data measured from its R G B sensors is then run through a whole lot of numbers and predetermined equations to figure out which white balance setting is most likely to be correct. Remember, white balance is the automatic adjustment that makes sure the white colour humans observe will also appear white in the image.

Setting your camera’s white balance to AWB will provide colour accuracy under many conditions. Your camera will adjust the white balance between 4000K – 7000K using a best guess algorithm. Auto white balance is a good choice for situations where the light changes over time and speed is an issue (e.g. animal photography, sports photography). However, you should avoid using auto white balance settings in the following situations:

  • Your scene is heavily dominated by one colour
  • Colour accuracy is absolutely imperative
  • You are photographing particularly warm or cool scenes (e.g. a sunset)

White Balance Presets

Most digital cameras come with multiple white balance preset options. These presets work well when:

  • The light source matches one of the preset white balance options
  • Your scene is heavily dominated by one colour

Shoot Sharp Digital Photos Without a Tripod

Like film cameras digital cameras are also sensitive to movements and shakings while shooting a photo. If the digital camera moves while the shutter is open the result will be a soft or blurry photo. Usually camera movements are very small and in high shutter speeds the camera does not have an opportunity to move enough in order to distort the digital photo. However in some scenarios such as slow shutter speeds, low ambient light and macro or high zoom photos even the tiniest movement will result in a blurry digital photo.

As a general rule photos that are taken with slow shutter speeds or high zoom values should be taken using a steady platform. The best steady platform is a tripod – but when a tripod is not available (for example when you travel and you do not want to carry a bulky and heavy tripod with you) there are some other methods and alternatives that you can use as a steady platform. Here are a few:

  • Lean the camera against a steady surface: you can use almost any surface that is steady in order to stabilize the digital camera. Such surfaces can be anything from a table, a wall, a bench or a light pole. Make sure that the surface is indeed stable by trying to shake it a bit with your hand. When taking the photo put the camera against that surface and apply some force (for example your weight) to make sure it does not move.
  • Place the camera on a horizontal surface: another option is to simply place the camera on a horizontal surface. The surface needs to be flat and stable. When you shoot the digital photo you should gently press the shutter button making sure that the camera does not move and then let go. Gravitation will make sure that the camera stays stable on the surface. The main problem with this method is that the camera might shake or bounce when the shutter button is pressed. To overcome this problem you can use two methods: delayed photo – set the camera to timer mode using the shortest time for example 2 seconds. When you press the shutter button the camera will start counting and will have enough time to stabilize before the photo is actually taken. Remote control – if you have a remote control use it to initiate the photo shooting instead of pressing the shutter button.
  • Image stabilizer enabled lenses: an expensive option that requires thinking ahead is the usage of lenses that include an image stabilizer. This technology can be implemented in a few methods for example using a floating optical element that compensates for movements or by using special software that controls the CCD sensor. Regardless of the technology such image stabilizers can effectively compensate for small camera movements and are commonly used by professional photographers taking high zoom photos.

Regardless of the method you use to stabilize your camera one thing to remember is that the more photos you take the higher the chances that one of them will be perfectly sharp and in focus. If the scenario is not easy to shoot and you are afraid that you might get blurry digital photos take your time a shoot a few photos using different stabilization methods and camera settings. You can later on browse through the photos and choose the best one.