As we have already found out, image quality depends on sensor size. The large sensor allows larger pixels as well, and they are capable of catching more light, which results in clearer and less noisy photos with color rendition.

But it is necessary to remember that sensor size doesn’t mean resolution and its measure units are not megapixels but inches or millimeters.

The majority of modern digital cameras have basically little, 1/3.2″ or 1/2.5″ sensors; some advanced compacts may possess larger, 1/1.8″ ones. At the same time, the number of megapixels increases from year to year although 6 megapixels or so would be enough to view photos on a computer screen or make average-size prints.

But only large sensor can justify the usage of so many megapixels. Bigger resolution, no doubt, means better detail and the possibility to print large photos but if sensor remains the same and the number of megapixels increases, the size of every single pixel suffers – they become smaller. On big resolution but little sensors pixels are so tiny that they can’t capture enough light and you receive noisy pictures.

Unfortunately, that is the way digital cameras’ manufacturers go: nowadays 12-megapixel compact cameras are quite standard, though sensors are as tiny as they used to be. Although compacts are equipped now with different noise reduction technologies, they can’t fully compensate for it as the increase in the quantity of pixels on the same sensor will lead actually to the decrease in image quality.

Average users night be confused by the numbers they give for sensor sizes: 1/3.2, 1/2.5 inches. What should be remembered here is that bigger numbers in the denominator mean smaller sensors. The table below shows the correspondence of those ambiguous inches to a sensor’s physical size.

The biggest but one value for sensor size is 36 x 24 mm that is a frame size in 35-millimetre film. Such sensors have full frame DSLR cameras. APS-C DSLRs use 22.7 x 15.1 mm (1.6 crop factor) or 23.7 x 15.6 mm (1.5 crop factor) sensors.

The price tag of a camera largely depends on the sensor that it houses. That’s why compacts are affordable and aim at the middle-of-the-road audience, and full frames are expensive camera for professionals.

DXG USA has launched the new DXG Luxe line of high-definition “couture camcorders” that offer a combination of high-quality video recording with fashionable design in a 1/2-inches thick body.

To the present moment there are two models in the line: the DXG-535VP Riviera and the DXG-533V Soho. The former features a chic, quilted pattern with silver or bronze details and crystal accents in three colors - pink, white or black. The latter comes in a hip pink or blue argyle pattern with stylish leather accents. Both of them come with a matching case complete.

As to their tech specs they are identical. Both models record high-definition video, namely 1280 x 720 pixels at 30fps, and can tale take 8-megapixel still photos (though actually they are interpolated from 5 megapixels).

The video is shot and still photos are composed with the help of a large 3-inch LCD screen. Unfortunately, neither camcorder has optical zoom, so you have to content yourself with 3x digital zoom.

“With the Luxe line, we’ve combined high definition video, high quality photo, great affordability and high fashion that gives consumers a distinctive device that stands out among a sea of silver and black,” said Paul Goldberg, senior vice president of sales and marketing at DXG USA.

DXG Luxe Camcorders - Specifications:

• Models:
  • DXG-535VP Riviera: Quilted pattern, pink, white or black, matching color crystals and hand strap
  • DXG-533V Soho: Argyle pattern, pink and gray or blue and gray, leather accents with folding clasp
• 3 inch TFT LCD Display
• CMOS Image Sensor
• Video Resolution: 1280 x 720/30fps
• 8 megapixels of Resolution (Still Photo)
• Maximum Aperture: F/3
• 3X Digital Zoom (video and still)
• Color Effects: color, black and white, sepia
• 32MB Internalmemory
• SD Memory Cards up to 16GB
• Dimensions: 4.3” (W) x 1.6” (D) x 2.6” (H), 8 ounces
• Power Supply: 4-AAA Batteries
• Price: $149.99

According to http://www.dxgusa.com.

Sigma 50-200mm ƒ/4-5.6 DC OS HSM is an update to the company’s previous telephoto zoom lens. The original 50-200mm was once upgraded to incorporate an in-lens motor, and then in 2009 again to provide optical stabilization.

The lens was designed specifically to fit the APS-C sensor, and it is incompatible with film or full-frame digital camera bodies. On a Canon body the lens offers 80-320mm range (1.6x crop-factor); on Nikon and others - 75-300mm range (1.5x crop).

The 50-200mm incorporates of HSM (Hyper Sonic Motor) for quiet and high-speed auto focus.

Handheld shooting is also improved. The lens’s OS (Optical Stabilizer) function eliminates the effects of camera shake allowing the use of shutter speeds 4 stops slower than normal for. It operates in conjunction with or an alternative to the cameras’ built-in OS System anti-shake function (if any).

The 50-200mm incorporates SLD (Special Low Dispersion) glass in the front lens group and is equipped with an inner focusing system that eliminates front lens rotation, making it suitable for use with circular polarizing filters. Super Multi-Layer Coating, in its turn, reduces flare and ghosting as well as provides high contrast images.

The lens ships with a circular-shaped lens hood, takes 55mm filters, and is available now for approximately $300.

Alternatives/Rivals: Pentax 50-200mm f/4-5.6 ED SMC P-DA, Tamron 55-200mm f/4-5.6 Di II LD Macro AF, Canon EF 55-200mm f/4.5-5.6 II USM, Nikon 55-200mm f/4-5.6G IF-ED AF-S DX VR Nikkor, Sony 55-200mm f/4-5.6 DT .

Slrgear.com:
With internal focusing and optical stabilization, there’s a lot to like about the new lens, especially considering the low price tag. It provides good performance when stopped down to ƒ/5.6 or ƒ/8 and.

Sigma 50-200mm ƒ/4-5.6 DC OS HSM – Specifications:

• Image Circle: APS-C
• Focal Length: 50-200mm
• Focal Length APS Equivalent:
  • 1.5x: 75-300mm
  • 1.6x: 80-320mm
• Maximum Aperture: ƒ/4 - 5.6
• Minimum Aperture: ƒ/22
• 8 Diaphragm Blades
• Lens Construction: 14 elements in 10 groups, with 1 SLD element
• Diagonal Angle of View (Based on image circle): 27.9 to 7.1 degrees
• Optical Stabilization
• Internal Focusing
• HSM with Full-Time Manual Override
• No Front Element Rotation
• Rotary Zoom System
• Closest Focus: 110cm / 43.3 in.
• Magnification Ratio: 0.22x / 1:4.5
• Filter Size: 55mm
• Available AF Mounts: Sigma, Canon, Nikon, Sony, Pentax.
• Typical Online Price: US$300