Powered By Blogger

Thursday, February 12, 2009

Sigma 18-50mm f/2.8 EX DC SLD ELD Aspherical Macro Lens for Canon Digital SLR Cameras

The characteristics of digital SLR cameras were taken into consideration when designing the lens power layout. The new advanced lens design corrects various aberrations. This lens provides the utmost correction against lateral chromatic aberration which is a serious problem for digital SLR cameras. This lens is specially coated to get the best color balance whilst cutting down flare and ghost caused by reflections from the digital image sensor and lens. It has excellent correction for vignetting and superior peripheral brightness is ensured. A Special Low Dispersion (SLD) lens and two aspherical lens elements provide excellent correction for all types of aberrations. The design produces a compact and lightweight, yet robust, construction with an overall length of 84.1mm (3.3in.) and maximum diameter of 74.1mm (2.9in.) and weight of 445g (15.6oz). This lens has a minimum focusing distance of 11 inches (28 cm.). It is equipped with inner focusing system. The non-rotating front lens element makes the lens suitable for using its petal-type lens hood and circular polarizing filters. Minimum Aperture - F22 Lens Construction - 15 Elements in 13 Groups Number of Diaphragm Blades - 7pcs Minimum Focusing Distance - 11in (28 cm.) Filter Size - 67mm Lens Hood - Petal-type hood Dimensions - Diameter 74.1mm (2.9 in.)X Length 84.1mm (3.3in.) Weight - 445gr/15.6ounces
Customer Review: great lens!
Just receive my 18-50 Lens on Sat and get to do some night landscape shoot with this lens ! the image is clear and sharp! focusing is fast with teh F2.8 stop... great lens for the price!
Customer Review: AF issues, Chromatic abberations too severe
Perhaps I was unlucky and got one of the bad ones but I found this lens completely unreliable. My first issue is the auto-focus (on canon 40D). I had more missed shots with this lens than I've ever had with any other..pretty slow AF also. I found the chromatic abberations unacceptable on a great number of shots as well. On the other hand, I took some beautiful macro shots with this lens. Particularly using live view with manual focus...fantastic. It seems that Sigma lenses are hit and miss QC wise from what I'm reading. Too bad because it really feels like a well built, quality lens. I returned mine to amazon as defective.


Sneak Peek

You will fall in love with the Acer 5920 at the first sight. This laptop comes in a rectangular form as every other laptop but its delicate curves give it a fine oval shape and to top it all its shiny black color adds to its beauty. In totality it gives the notebook a sense of quality and yet it has not been open. But once you open the notebook you find a pleasant contrast. The inside of the laptop comes in a cream color ceramic finish. It feels good to see the light distinction compared against the dark outer surface.

Design

The design of Acer 5920 is obviously a key part of its appeal, but it does not make the performance and functionality any lesser. Indeed, the notebook continues to make an impression in this area too with an outstanding requirement. At the core of Acer 5920 is a new Santa Rosa certified Core 2 Duo T7300 2.0GHz CPU, with 800MHz Front Side Bus. This is the third fastest of the four new Santa Rosa Core 2 Duo's.

Core Information

The keyboard has shortcut keys on its sides. You will find the media playback keys on the right and on the left side you will find miscellaneous functioning keys such as Wireless, Internet, Mail and Bluetooth. One thing to notice over here is that the media keys are very receptive to touch. This can create some problem when you are doing some important work. But with time you will get used to it and keep in mind to avoid touching it. Other orderly touches include USB logos on either side which indicate where the USB ports are, as well as a middle click button that doubles as a scroll wheel, and the 0.3 megapixel camera that's cleverly integrated into the clip for the lid.

Cutting Edge Technology

The Acer 5920 is also supported with a 1 GB turbo memory module. It helps in utilizing ReadyDrive and ReadyBoost. Another remarkable feature of the notebook is the Dolby Home Theatre. The audio hardware is provided by RealTek which includes Dolby's Digital, Digital Live, Pro Logic II, Headphone and Virtual Speaker technologies. These are great features to have but to top it all its Dolby Headphone is the real draw, adding superb surround effects to games and films when using headphones.

Conclusion

The Acer 5920 is a very stylish laptop with all the useful technologies that will be needed by you.

Pooja Lapasia is a well known author and has written articles on Laptop Computers, Laptop store, Acer Laptops, online shop and many other subjects.

Wide Collection of Mbt Shoes