Saturday, April 25, 2009

How to take beautiful landscape pictures?

Fill the frame for dramatic effect

Look carefully at the picture you’re framing before you click the button. Experiment by moving the camera up and down, side to side. Tilt the camera to various angles and see what it shows you. Fill the frame with the object that interests you most. If your digital camera has an LCD screen, you can use it to improve your sensitivity to the entire scene.

Change your perspective

There’s no need to shoot everything from a standing position. Sometimes sitting, crouching or getting higher can produce a more interesting shot.

Color

The presence of colors is probably the best hint of a great photography potential. Red is the most pleasant color for the eye. If you manage to find this color or a hue in nature, even in small spots, set up your tripod and prepare your camera. If you also pay attention to the position of these colored spots in the image, it is very possible that you obtain a good picture.

For increased drama, you can easily convert color photos to black and white by using your favorite image-editing program. With some camera models you can even do this in the camera before downloading the image to your computer. Once the image is on your computer, you can use your image-editing program to adjust contrast and brightness. Silhouettes look terrific in black and white, as do old buildings. The effect adds drama.

Clouds

The most beautiful ones are the clouds above the horizon, close to the landscape area that you have in view. At twilight or crack of dawn these clouds may have astonishing colors. They may create a dynamic and complementary center of interest that may give intensity to the center of interest in the picture.

Calmness

A calm, windless atmosphere may sometimes be very useful for the landscape photographer. The wind alters flowers, leaves, trees, grass, lakes and water basins. Do you take pictures of the landscape you will probably not see very soon holding the camera in your hand? It would probably be more cautious to use a tripod, preferably a good one.

Weather

Bad weather may be very good for taking pictures. Fog, mist, snow or rain may give fantastic power and impact to some every day landscapes.

Geographical position

Whenever possible, try to place yourself at north or (especially) south from the landscape you want to take pictures of, because you will thus benefit from lateral light. This sort of light emphasizes the relief and textures, the shapes and shadows.

Close-up

The best landscapes are usually those containing a powerful close-up. Trees, bushes, rocks, bunches of grass or moss, dunes of sand, flowers, almost every subject may be used to create a particular depth in the image. Such a detail may give a three-dimensional illusion, which is very important for the impact of the image.

Reflections

Peaceful waters offer perfect occasions for taking mirror images. This effect may be used in order to double the beauty of a landscape.

source : www.digital-cameras-help.com
More details..

Wednesday, April 15, 2009

DIGITAL CAMERA SENSORS

A digital camera uses a sensor array of millions of tiny pixels in order to produce the final image. When you press your camera's shutter button and the exposure begins, each of these pixels has a "photosite" which is uncovered to collect and store photons in a cavity. Once the exposure finishes, the camera closes each of these photosites, and then tries to assess how many photons fell into each. The relative quantity of photons in each cavity are then sorted into various intensity levels, whose precision is determined by bit depth (0 - 255 for an 8-bit image).

Each cavity is unable to distinguish how much of each color has fallen in, so the above illustration would only be able to create grayscale images. To capture color images, each cavity has to have a filter placed over it which only allows penetration of a particular color of light. Virtually all current digital cameras can only capture one of the three primary colors in each cavity, and so they discard roughly 2/3 of the incoming light. As a result, the camera has to approximate the other two primary colors in order to have information about all three colors at every pixel. The most common type of color filter array is called a "Bayer array," shown below.




A Bayer array consists of alternating rows of red-green and green-blue filters. Notice how the Bayer array contains twice as many green as red or blue sensors. Each primary color does not receive an equal fraction of the total area because the human eye is more sensitive to green light than both red and blue light. Redundancy with green pixels produces an image which appears less noisy and has finer detail than could be accomplished if each color were treated equally. This also explains why noise in the green channel is much less than for the other two primary colors (see "Understanding Image Noise" for an example).

Note: Not all digital cameras use a Bayer array, however this is by far the most common setup. The Foveon sensor used in Sigma's SD9 and SD10 captures all three colors at each pixel location. Sony cameras capture four colors in a similar array: red, green, blue and emerald green.
BAYER DEMOSAICING

Bayer "demosaicing" is the process of translating this Bayer array of primary colors into a final image which contains full color information at each pixel. How is this possible if the camera is unable to directly measure full color? One way of understanding this is to instead think of each 2x2 array of red, green and blue as a single full color cavity.

This would work fine, however most cameras take additional steps to extract even more image information from this color array. If the camera treated all of the colors in each 2x2 array as having landed in the same place, then it would only be able achieve half the resolution in both the horizontal and vertical directions. On the other hand, if a camera computed the color using several overlapping 2x2 arrays, then it could achieve a higher resolution than would be possible with a single set of 2x2 arrays. The following combination of overlapping 2x2 arrays could be used to extract more image information.

Note how we did not calculate image information at the very edges of the array, since we assumed the image continued on in each direction. If these were actually the edges of the cavity array, then calculations here would be less accurate, since there are no longer pixels on all sides. This is no problem, since information at the very edges of an image can easily be cropped out for cameras with millions of pixels.

Other demosaicing algorithms exist which can extract slightly more resolution, produce images which are less noisy, or adapt to best approximate the image at each location.
DEMOSAICING ARTIFACTS

Images with small-scale detail near the resolution limit of the digital sensor can sometimes trick the demosaicing algorithm—producing an unrealistic looking result. The most common artifact is moirĂ© (pronounced "more-ay"), which may appear as repeating patterns, color artifacts or pixels arranges in an unrealistic maze-like pattern:

Two separate photos are shown above—each at a different magnification. Note the appearance of moirĂ© in all four bottom squares, in addition to the third square of the first photo (subtle). Both maze-like and color artifacts can be seen in the third square of the downsized version. These artifacts depend on both the type of texture and software used to develop the digital camera's RAW file.

MICROLENS ARRAYS

You might wonder why the first diagram in this tutorial did not place each cavity directly next to each other. Real-world camera sensors do not actually have photosites which cover the entire surface of the sensor. In fact, they often cover just half the total area in order to accommodate other electronics. Each cavity is shown with little peaks between them to direct the photons to one cavity or the other. Digital cameras contain "microlenses" above each photosite to enhance their light-gathering ability. These lenses are analogous to funnels which direct photons into the photosite where the photons would have otherwise been unused.

Well-designed microlenses can improve the photon signal at each photosite, and subsequently create images which have less noise for the same exposure time. Camera manufacturers have been able to use improvements in microlens design to reduce or maintain noise in the latest high-resolution cameras, despite having smaller photosites due to squeezing more megapixels into the same sensor area.

For further reading on digital camera sensors, please visit:
Digital Camera Sensor Sizes: How Do These Influence Photography?

More details..

Sunday, April 5, 2009

Swimming Child




More details..
11

Sony Cybershot DSC-H50 Digital Camera

The Sony Cybershot DSC-H50 is a compact, 9.1-megapixel digital camera with an impressive image-stabilized 15x Carl Zeiss f/2.7-4.8 optical zoom lens and a 3-inch tilting LCD monitor. The DSC-H50 features Face Detection, Smile Shutter and Intelligent Scene Recognition technologies, as well as video recording, HDTV compatibility and a remote control.

Sony Cybershot DSC-H50 Pros
  • 15x zoom lens with Super SteadyShot optical image stabilization (31-465 mm equivalent).
  • Very good image quality.
  • Exposure settings ranging from Easy Mode to full manual control.
  • Compact size and light weight.
  • Large, tilting LCD monitor.
  • MPEG video recording with zoom functionality.
  • Easily accessible continuous shooting/bracket button.
  • Remote control - great for group and self-portraits.
  • In-camera editing and slideshow functions.
Sony Cybershot DSC-H50 Cons
  • Optical viewfinder is so small it’s almost useless.
  • Somewhat awkward physical design and user interface.
  • Battery for remote control is difficult to access.


Sony Cybershot DSC-H50 Features

The best thing about the DSC-H50, as far as I’m concerned, is its image-stabilized, 15x optical zoom lens. That’s a 35mm equivalent of 31mm to 465mm, a hell of a zoom capacity, especially on a camera this small and light. (However, recent entries in the superzoom market from Kodak, Olympus and Nikon have upped the zoom ante to 24x and 26x. At what cost to image quality remains to be seen.) I loved being able to zoom in on faraway subjects, such as ancestral Pueblo cliff dwellings from distant overlooks. I could see details through the zoom lens that I could not see with my naked eye. Who needs binoculars when you have a 15x zoom lens?Image stabilization is critical a crtitical feature for the H50. Without it, shooting at full zoom length without a tripod would be next to impossible. Sony’s Super SteadyShot optical image stabilization minimizes blur from camera movement with a built-in gyro that senses movement and then compensates for it by moving the lens elements. This also means more sharp photos when you’re shooting in low light.

The 3-inch, tilting LCD monitor is big, vivid and very useful for shooting from high or low vantage points where you otherwise might not be able to see the display. It’s the first time I’ve used a camera with a tilting LCD and I liked it a lot. However, I did wonder why Sony didn’t go one step further and make it a swivel LCD so it could be viewed from various additional angles. I’ve seen other cameras with LCDs that tilt and swivel and it seems like that would be handy.
The DSC-H50 has a full range of exposure modes, from Easy to full manual, with program auto, shutter priority, aperture priority and several scene modes in between. This makes it an ideal family camera: Set it to Easy mode and hand it to your kid to fool around with; set it to Auto Adjustment or a scene mode like Portrait for your spouse; set it to Manual when you want total creative control.

All Sony Cybershot DSC-H50 Camera Menus

Intelligent Scene Recognition, Face Detection and Smile Shutter are much-touted technological innovations that are great — when they work. In my experience with this camera, Intelligent Scene Recognition worked reasonably well; Face Detection worked so well it even recognized faces in artwork; and Smile Shutter was unreliable at best. Personally, I think Smile Shutter is rather silly, anyway. Is it really so difficult to observe your subject and push the shutter button when they smile? What would be more useful, I think, is if camera makers developed an Eyes Open feature that only takes pictures when all subjects’ eyes are open.

Night Shot is an interesting concept, although I’m not sure I entirely understand it. The manual says: “The Night Shot function lets you shoot subjects in the dark places without using the flash.” Switching Night Shot on reveals a display message that says, “Illuminate subject using infrared light in low light,” and turns on a faint, red light on the front of the camera. Experimenting with Night Shot around my dimly lit house at night, I captured grainy black and white photos with a greenish cast. I prefer the color results I got using Auto Adjustment with the flash turned off. Besides offering a slightly faster shutter speed in very low-light situations, the only real benefit I can see to Night Shot is that its infrared lamp illuminates subjects without the red glow of the focus lamp. This could be useful during theater performances - or perhaps special ops missions in “the dark places” referred to in the manual.

The included remote control is a fantastic accessory - one that quickly convinced me all cameras should come with them. It makes shooting group and self-portraits easy as pie. Just set the camera up on a tripod or other solid surface and set the exposure mode and zoom length, then go pose. When you’re ready, push the shutter button on the remote. Change poses, push the shutter button again. And again. It will keep taking pictures: No self-timer or running back and forth necessary.

Sony Cybershot DSC-H50 Design

According to Sony’s specifications, the DSC-H50 weighs 14.6 ounces (415 g) without the battery and Memory Stick and 1 pound, 3.3 ounces (547 g), with them. It measures 4 9/16 x 3 3/16 x 3 3/8 inches (116.1mm x 81.4mm x 86.0mm). In real-life terms, this translates to a camera that will fit in a medium- to large-sized purse or pack or that can be worn on a neck strap with little weight penalty. It will not fit in a pocket, unless you have especially roomy jacket pockets. Compared to an average DSLR camera body with a kit zoom lens of 200mm or so, the DSC-H50 is a real space-saver. And a somewhat comparable DSLR zoom lens like the Nikon 80-400mm AF-S VR zoom would weigh three pounds - camera not included.

It’s hard to pinpoint why, but this camera does not feel particularly comfortable in my (large-ish female) hands. It’s very difficult to hold or even pick up left-handed, and although I am right-handed, there is really only one way to hold it that feels secure, which is with the right-handed grip. And even that isn’t really comfortable. This lack of ergonomic ease is only a minor impediment, but it does contribute to my sense that this camera is not the best fit for me. I’ve used other compact digital cameras that felt much more comfortable in my hands.

The mode dial on top of the camera accesses exposure and scene modes. The control button’s four-way navigator allows you to quickly select settings for focal length, self-timer, flash and how much information is displayed on the LCD. The wheel dial around the control button lets you adjust ISO, shutter, aperture and other manual options.

More details..
4