Posted by admin February - 18 - 2011 Comments Off

The digital cameras megapixels madness is very similar to the personal computer Mhz madness back in the 90s. The number of pixels a camera uses to produce a digital photo is just one element in determining the photo quality. Another important element that is usually forgotten is the sensor size. Here is why.

Digital cameras use an electronic sensor (also known as a CCD) in order to capture a digital photo. This sensor replaces the old film rolls used by traditional cameras. The electronic sensor is built from small light sensors also known as pixels. When you take a photo the camera opens the shutter for a certain amount of time. During that time light hits each individual pixel. The amount of light that hits each pixel determines its intensity (also known as the pixel value). A digital photo is comprised of many pixels each with its own pixel value.

There is a direct relationship between the size of the CCD the digital camera uses, the number of megapixels it supports and the size of each pixel. For a fixed CCD size the more pixels the CCD supports the smaller each pixel is. On the other hand for a CCD with a fixed number of pixels, the larger the CCD the bigger each pixel is.

So why should you care about the pixel size? There are many reasons to care about the pixel size as it plays an important role in the overall quality of your digital photos. One reason that is very easy to understand is sensitivity to light. Assume that you are taking a photo with the shutter opened for a fixed amount of time. During that time light hits each pixel. The larger a pixel is the more light energy that it accumulates during that period of time. The result is that with larger pixels you could take photos in darker scenarios than with smaller pixels. Also – with larger pixels the amount of noise in each pixel value is reduced.

For example if you have two digital cameras both having the same number of pixels but one is using a larger CCD sensor – the camera with the larger CCD will be able to take digital photos that are sharper and with less noise. It will also be able to take digital photos in scenes that are too dark for the other camera. Higher light sensitivity also allows more flexibility with both shutter speed and aperture settings.

High end cameras like digital SLR use larger CCD than point and shoot digital pocket cameras. Why is that? The main reason is simple: cost. It costs more to manufacture a larger CCD (for reasons such as yield and other specific manufacturing processes issues). The CCD size also influences other optical attributes of the camera – for example the aperture needed in a specific scene changes as the CCD size changes. The depth of field is directly influenced by such aperture changes.

In conclusion, when buying a digital camera always remember not to get fixated on the number of pixels. Although this number is important it is not a standalone feature. If you plan to take digital photos in extreme conditions, if you do care about depth of field, aperture settings, shutter speeds and light sensitivity than you should also check the size of the CDD the camera uses among other optical parameters of the camera.

Ziv Haparnas is a technology veteran and writes about practical technology and science issues. This article can be reprinted and used as long as the resource box including the backlink is included. You can find more information about photo album printing and photography in general on http://www.printrates.com – a site dedicated to photo printing.

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Posted by admin February - 18 - 2011 Comments Off

Computer Mice

Every computer user can hopefully identify their mouse and the importance it plays in the daily operation of their computer. Mice are nothing new and for the most part are nothing overly complex, but the average user may not be familiar with all of the options and technologies that may go into these little devices. This Tech Tip will take a look at some of the features of mice that people may take for granted, or may otherwise be unaware of.

Tracking Technologies

Mechanical mice – Mechanical mice were the first ones used on computers, and can still be found for sale, despite the advances of tracking technologies. These mice feature a hard ball on the underside that rolls as the mouse is moved, and rollers inside the mouse allow the physical motion to be translated to the pointer on the screen. Some “ball mice” are a bit more advanced and replace the internal rollers with optical sensors, but the same principle applies.

Mechanical mice require occasional maintenance to keep the ball and rollers free of lint and other debris, and with numerous moving parts there is always a potential for problems. The use of a mouse pad is recommended for these mice as they not only provide a clean surface to work on, but also provide the needed resistance for the ball to roll smoothly.

The precision of mechanical mice is not particularly good, and although they may be fine for typical desktop work, they were never quite up to the task of detailed graphics work or serious game playing.

Optical mice – Optical mice replace the whole ball/roller assembly of mechanical mice with a beam of a light and an optical sensor. The beam of light shines down on the surface below the mouse and the sensor uses the light to track the movement. The images included with the listing for this optical mouse (http://www.geeks.com/details.asp?invtid=HTM-39GWT&cat=MOU) provide a glimpse at the bottom of the mouse, where the light and sensor can be seen.

Optical mice have several advantages over mechanical mice. There are no moving parts to break or otherwise cause problems. The need for maintenance is greatly reduced as the bottoms have no openings or rollers to collect lint. Although mice generally aren’t heavy, the elimination of the ball and roller mechanism allows an optical mouse to be much lighter than a comparable mechanical mouse. The precision of optical mice is also much greater than mechanical mice, and the resolution can go from the low hundreds to the high hundreds (as measured in dpi, dots per inch).

Another advantage is that the need for a mouse pad may be eliminated with an optical mouse, as they do best while tracking on any smooth, flat surface. A clean desktop is generally good enough, but those looking to take the precision of optical mice to the highest level may opt for a performance “mousing surface”. There are several precision mousing surface manufacturers, such as XRay Pads (http://www.xraypad.com/) and FUNC Industries (http://www.func.net/), that design pads to appeal to game players and others who demand the best performance.

Laser mice – Laser technology is the latest and greatest in computer mice tracking, and takes the advantages of optical to a new level. Most of the attributes of a laser mouse have been described in the optical mouse section, except for one. Instead of a fairly wide beam of light, it uses an extremely narrow beam of laser light.

The Logitech MX1000 laser mouse may be the mouse for you if you are looking for extreme precision. According to Logitech, the laser technology used in the MX1000 provides up to “20x more sensitivity to surface detail–or tracking power–than optical.”

Hard Wired Connection Technologies

Serial – Serial mice are fairly difficult to come by these days, as are the ports they need in order to operate. This technology is quite old and slow, and the popularity and convenience of USB has all but eliminated the need for this interface on your typical PC. But, there were mice that sported the 9-pin connection needed to connect to a serial port, and many PS2 mice used to include an adaptor for Serial ports.

PS2 – PS2 mice were the standard for a long time, as all motherboards provided two PS2 ports for connecting a keyboard and a mouse. USB technology has become so widely used that the slower and less convenient PS2 ports are on the verge of extinction with the Serial port. That said, not many mice are still sold that only support a PS2 connection, but there are still some available.

USB – Most mice can now connect via USB, and include an adaptor to be used on a PS2 port, as well. It seems that just about any mouse now uses USB to connect, whether it is a wired mouse, or any variety of wireless mice that we are about to look at.

Wireless Connection Technologies

Radio Frequency – The most common type of wireless mouse uses radio frequencies to communicate motion to a receiver that is connected to the PC. This generic wireless mouse (http://www.geeks.com/details.asp?invtid=RF-M308-RC-USB&cat=MOU) operates on the 27MHz frequency and the mouse itself is powered by AAA batteries which are not included. As you move up the price scale of RF (Radio Frequency) wireless mice, the packages will generally include an integrated rechargeable battery, as does the Logitech MX1000 discussed previously. Other features of higher end RF wireless mice include extended range, greater precision, and a receiver that doubles as a battery charger.

Bluetooth – The Tech Tip on Bluetooth discussed the basics of this wireless technology, and how it was a good fit for ‘lower speed’ devices, like a mouse. Logitech and IOGear are two manufacturers offering products for Bluetooth users, in addition to more traditional mice. The Bluetooth mice are also battery powered, and use the 2.4GHz radio frequency to communicate with an included receiver/charger or other Bluetooth adaptor.

RFID – A truly unique approach to wireless mice has been developed by a company called A4Tech. The A4Tech ND-30 RFID wireless mouse must be used with the included mouse pad in order to function, but there are no batteries in the mouse, and no cords on the mouse to get in the way. It works by using electro magnetic induction between the pad (which is plugged into a USB port) and the wireless, non-powered mouse. You never have to worry about replacing / charging batteries, and the weight of the mouse is greatly reduced since the power features are no longer necessary.

Features

Buttons – Most mice (except for a Macintoch’s) include at least two buttons. The use of these is fairly well understood, but other buttons may be featured on a mouse to further simplify common tasks. The Logitech MX 510 mouse features a total of 8 buttons which can be programmed to execute functions of the user’s choosing.

Scroll wheels – Many mice now include a scroll wheel between the two main buttons which serves to allow up/down scrolling of documents and web pages. The scroll wheel may also serves as a third button on some mice, and clicking the scroll wheel will activate commands in many applications. More advanced scroll wheels are found on some mice that allow for left to right scrolling, which may be useful on a wide spreadsheet or large image.

Extra features – Many mice provide more than the basic functionality we have come to expect. Some provide a reduced foot print in order to make them more portable for use with a notebook computer. Some are designed for multi-tasking and provide an integrated flash memory card reader. Then, there are others that just look cool with a bit of a light show, or that actually keep you cool by including a small fan in the palm rest area.

Final Words

On the surface, computer mice are fairly simple devices that may not receive the attention they deserve by end users. Selecting a high quality, ergonomically designed mouse can do wonders for productivity and comfort, and the options available should allow anyone to find the right mouse for their personal preferences.

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Posted by admin February - 18 - 2011 Comments Off

The price of the micro electro mechanical system and the sensor is reducing the recent years, because their processing technology has become mature. The application ranges from the automotive and military industry to the consumer electronic areas, such as the smart phone, tablet device, connected television, game console. It is predicated that these four terminal applications will be the main driving force of the MEMS and sensor market.

The functions of the smart phone, which is based on the powerful operating system and numbers applications, has is unlimited by the voice communication. The touch panel, MEMS accelerometer has been applied by the smart phone early. Adding the other components, such as gyroscope, magnetometer, barometer, makes the functions perform better. It is predicated that the permeability of the smart phone will reach forty-five percent in the year of 2013.

Unlike the netbook which is used in the office, the environment of the tablet device is more complicated. The touch panel, MEMS accelerometer and MEMS gyro are installed in the devices to replace the traditional keyboard and strengthen the operating experience. It is predicated that the permeability of the tablet device will reach twenty-seven percent in the year of 2013.

The connected television needs the smoother interface when compared with the traditional remote control television; therefore, the remote control should apply the touch screen and leadin the operating interface design, such as the MEMS accelerometer and MEMS gyro. The content of the connected television will be perfect after the Google TV is released. It is predicated that the shipment of connected television will reach one hundred million sets.

The innovation of the game operating interface decides the market of family video game. The Nintendo has occupied the family video game market, and the Sony, Microsoft has decided to use the optical sensor to attract the customers. The related integrated circuit is MAX487ECSA.

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