Photographie and Sound health

The fact is that human eyes are also equivalent to a camera with an optical sensor screen and lens system. The pupil of the eye contains an organic fluid lens with adjustable focal length. Depending on the distance of the object we focus, its focal length directly varies. When any light falls on the adjusting tissues around the pupil, they just absorb all wavelengths from it and reflect a particular red wavelength alone which is negotiable to normal visible spectrum. Thus when we look into a normal person’s eyes, the pupil looks to be black in colour. But if immensely bright light falls on the pupil, the reflected red wavelength will be visible to our eyes. So when capturing human faces using a flash or with any bright light source behind the camera, the reflected red light will be recorded as the pupil’s colour in the image. This is known as the red eye reflection effect which makes the person in the image look as though he has got a monster’s eye. Presently almost all the latest DSLR’s as well as film cameras have got the red eye reduction option to prevent red eye effect by default when we capture the image. But, this has found to reduce the red eye effect up to a certain extent. So after the image is captured, image editing software like Photoshop has got the red eye removal tool which completely removes the red eye effect by itself and makes the pupil look black in colour.

CCDs, like CMOS chips, use microscopic lenses to focus incoming beams of photons onto the photosensitive areas on each individual pixel/photo site on the chip’s photodiode grid. In a CCD, the sensitive area of individual photo sites relative to the overall size of the photo site itself is relatively large, often amounting to as much as 95 percent of the total area. That makes a CCD particularly efficient in capturing light. As photons fall into this photo site bucket, the bucket fills. If, during the length of the exposure, the bucket receives a certain number of photons, called a threshold, then that pixel registers an image. If too few pixels are captured, that pixel is considered black. The more photons that are grabbed, the lighter in color the pixel becomes until, when it’s full, the pixel is deemed white. In-between values produce shades of gray or, because of the filters used, various shades of red, green, and blue. If too many pixels fall into a particular bucket, they may actually overflow, just as they might with a real bucket, and pour into the surrounding photo sites, producing that unwanted flare known as blooming. This effect is often more pronounced in CCD sensors, which can be easily oversaturated with light. The only way to prevent this photon overfilling is to drain off some of the extra photons before the photo site overflows, and the CCD’s pixels can’t include the circuitry to do this. Of course, now you have a bucket full of photons all mixed together in analog form like a bucket full of water. What you want though, in computer terms, is a bucket full of ice cubes, because individual cubes (digital values) are easier for a computer to manage than an amorphous mass of liquid. The first step is to convert the photons to something that can be handled electronically, namely electrons. That’s done right in the photo site, but the result is still a fluid (analog) collection of information. So, the analog electron values in each row of a CCD array are piped in unison down their individual columns to the bottom row of the sensor. When each row of charges reaches this area, called a transfer register, the charges are converted into an analog voltage, amplified, and then piped off the chip to the external electronic circuitry in the digital camera. The camera’s circuitry performs the conversion from analog (liquid) form to digital (ice cubes). The process is repeated for each row (called sweeping the image off the chip), and eventually the CCD is cleared and the image is completely converted from analog to digital form. Unfortunately, because the CCD imager is so dumb, the external circuitry outside the chip has to be that much smarter, containing oscillators, clock drivers, and timing components to make sure that retrieving an image from the chip happens in an orderly manner. All these pixels crunching require processing time and power and are theoretically much slower. Worse, this processing involves every photo site on the chip for every picture you take, even if you aren’t using the full area of the sensor for a particular photo.

CMOS sensors and their grids of photodiodes operate something like CCD imagers in the sense that each photo site can be compared to a bucket that fills with photons that are directed onto the photosensitive area by a micro lens. However, a CMOS sensor photo site contains lots of circuitry not found in a CCD photo site and so there is less room for the photosensitive area. In some CMOS sensors, the sensitive area may be about 50 percent of the total area of each photo site. The same thresholds and bucket-filling analogies apply to how CMOS captures photons. However, unlike CCD chips, the electrons are converted to digital form right within the individual photosets. Circuitry converts the photons to electrons (as in a CCD imager) but then transforms the charge into an amplified voltage value. CMOS sensors can include a kind of pixel-resetting circuitry to, more or less, bleed off excessive photons before they can overflow to the adjacent pixels. So, CMOS chips are much, much less prone to blooming effects. The whole process is more efficient, because all the signal processing can be handled in parallel and with less energy consumption. “Sweeping” the image off the chip by rows and columns isn’t necessary. Every photo site on a CMOS imager can be accessed directly. The circuitry found in a CMOS imager is basically similar to that in standard chips such as RAM, so CMOS sensors can be produced using the same equipment and production lines, in contrast to CCD chips which require special fabrication methods. So, CMOS sensors can be relatively inexpensive compared to CCD on a pixel-by-pixel basis. On the other hand, the smaller photosensitive area of these chips makes it more difficult to produce high-quality images, and the resulting sensors are less sensitive to light, too.

People are very busy in today’s world with their cyclic lives and hardly have time to relax. Weekdays fly just like that working continuously and they spend their weekends by taking good rest or by having a little entertainment with their televisions. The same cycle repeats over and over again throughout their life. But this is not at all ideal for healthy living. Obviously we must work but that doesn’t mean that we must lose our health for our work and earnings. Here is a good idea to keep ourselves healthy on our daily go. We find that very few people have the habit of going for a morning walk and for a session of exercise before they begin their day. This is a very good habit that keeps us fit, active and healthy. Taking a morning walk everyday boosts up our energy and we would never feel tired throughout our day. Moreover this gives us a very good sleep at night. Jogging along with exercise is preferably good because it not only makes us active nut also burns up our extra calories and keeps us fit. Jogging increases blood circulation and keeps us far away from cholesterol and various heart problems and eventually adds years to our life span.

Because most digital SLR photographers were already seasoned veterans before they began using a DSLR, they already have a considerable advantage over neophyte photographers who must master digital technology at the same time they are learning photographic basics. For example, you already know not to shoot into the sun unless you want to produce a silhouette, and wouldn’t think of using your camera’s built-in flash from the last row in the balcony to capture a photo of Bono pacing the stage at a U2 concert. You know to hold the camera steady in dim light and how to make a background less prominent by throwing it out of focus. You understand terms like lens flare, motion blur, and grain, and may have more than inkling about things like solarisation, halftones, mezzotints, or sharp less masking. There are other photographic concepts that you already understand that you can put to use with your digital SLR.

Basic composition: Seasoned photographers know how to line up shots to produce a pleasing composition. You’ll find this skill valuable with DSLRs, because their WYSIWYG viewpoint makes composition more precise.

Choosing lenses: Beginners don’t choose lenses or zooming settings. They just zoom in or out to make the image appear to be the size they want. Photographers understand that lens choice is an important part of the creative process to say, compress the apparent distance between objects, emphasize the foreground, or produce pleasing portraits.

Using selective focus: Point-and-shoot cameras generally don’t offer much flexibility in applying depth-of-field. Your understanding of selective focus will let you place the emphasis in your pictures exactly where you want it.

Choosing a film “look”: If you’re a veteran film photographer, you’re used to choosing one film because it provides vivid, saturated colours even on overcast days or another film because it has accurate flesh tones for portraits, or a third because it has extra contrast that makes product shots look their best. You can apply this knowledge to your digital camera to select saturation, contrast, and exposure settings that suit the exact look you want.

Knowledge of what you can do in the film and digital darkroom: Experienced photographers know how and when to take advantage of image-editing techniques, such as retouching, compositing, colour correction, and special effects. These can be used to fix problem images, or make a good image a great one.

All the captured images and pictures are stored in a memory drive present in the DSLR. There are various types of memory drives that are available especially for DSLR cameras. Predominantly Compact Flash drives ere used as the memory drives in most DSLRs. The Compact Flash drives are a little big in size and have got enough memory to store and are comparatively quick in access than all other drives that are available for DSLRs. DSLR’s of greater than 6megapixels often store as TIFF or any other loose less formats which require large capacity memory drives. So, mini hard drives were used in such cameras. Mini hard drives like the ones introduced by IBM can be used in the same slots that are for Compact Flash drives. But now Compact Flash drives of capacity 4GB and 8GB have been introduced for higher end DSLR cameras. Secure Digital cards are one of the most popular storage drives of DSLR. They are available in capacities of 256MB, 512MB, 1GB and 2GB. The higher memory versions are found to be slow in access. 512MB SD card is the most precise one for DSLRs. Some cameras also use Multi Media Cards (MMC) for storage which are comparatively slower in access than SD cards.