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.

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TechFuel® Travel Battery Charger for Canon EOS Digital Rebel XT Digital Camera

This TechFuel® Battery Charger is specifically designed to charge the batteries for your Canon EOS Digital Rebel XT Digital Camera. TechFuel® Battery Chargers feature the latest battery charging technology, the highest quality components, and meet or exceed OEM specifications. TechFuel® Battery Chargers are designed to charge your battery in the most efficent manner possible. All TechFuel® products have a one-year limited warranty and a thirty-day money back guarantee. The TechFuel® name, images, and contents of this Batteryheads listing are protected by trademarks and copyrights. Copyright © 2008 Batteryheads

Composition in nature photography comes easy to some, but many new photographers struggle to find their balance. This is especially true where wildlife is concerned.

There is a bit of false wisdom about that says: "You should never put your animal right in the middle of the photo - only to the left or the right." This is simply not true, but it is a notion that causes all sorts of anxiety for new photographers.

If you don't put your animal in the middle of the photo, where do you put it? And what do you do with all that extra space? Well, it may (or may not) encourage you to know that there is not really any hard and fast rule to answer these questions. Like all things in composition, it really depends on your own sense of visual balance. So good composition requires you to have the confidence to trust your own judgment.

That doesn't mean you are on your own when it comes to learning composition. The answers to the following questions may help you if you are struggling to get started.

Question #1. Can I Position My Subject In The Middle? In certain situations this can work just fine. If you are shooting a portrait-style photo where the animal subject fills up much of the frame, it can make sense to place it right in the centre. This approach can seem perfectly natural, especially when the subject is looking right at the camera. In this case there is nothing to indicate a shift to one side or the other, and to do so may just create wasted space.

For this type of photo, where the subject fills most of the picture, it is important to leave a bit of breathing room around the head of the subject. Your picture will look more balanced if there is a little space between the subject and the edge of the frame, rather than showing the subject cramped into the composition.

Question #2. Should My Subject Go On The Left Or The Right? Your answer to this question should be guided by the physical positioning of the subject. As a general rule, it is preferable to have your subject looking toward the middle of the picture, rather than toward the edge of the frame. So if your subject is facing to the left, shift its position a little to the right, and vice-versa.

It is not necessary to move the subject all the way over to one side. In fact many of my wildlife photos show the head of the animal right in the centre of the picture, with the body leading in from one side or the other. So the position of the subject is only slightly to the left or right. The important thing is that there is more space in front of the subject than behind it.

Question #3. What Do I Do With All That Extra Space? If you get the balance right in a portrait-style photo, the extra space will not appear too empty. In fact, it looks quite natural to have a little empty area for your subject to look into.

Problems can arise when you take your photo from further away, with a lot more space around the subject. This is when you really have to do some creative thinking about how to put that extra space to work in your composition.

The more space that appears around the subject, the more information you reveal about the environment it was photographed in. As an artist, it is up to you to make that work for you. I always believe in the principle; "Anything that does not make my photo better, makes it worse." You need to ask yourself if showing more of the surroundings actually adds to the impact of the photo. If not, you may be better to zoom in and eliminate the extra space. However, the surroundings can add interest and impact to a picture if you know how to use them well.

You already know that if your subject is facing to the right, you should position it to the left so that it looks into the picture. In that case, if you have another object that adds interest, you should try to position it to the right - so the animal is facing towards it. The idea is to try to establish a relationship between the animal and the surroundings. If you do this well, all the elements of the composition will be working together, adding to the impact of the entire picture.

For example, imagine a bird on a branch alongside some flowers. If the bird is facing away from the flowers, they are just two random objects in the same photo. But if the bird is facing toward the flowers, your photo tells a completely different story.

This may sound simple, but good wildlife photos are the result of patience, perserverence, and lots of wasted exposures before you get that perfect shot. However, don't think of them as wasted exposures. Every time you press the shutter you add to your experience, and it is with experience that you will begin to trust your instincts and settle on a style of composition that expresses your love of the subject.

Composition, aperture, shutter speed, depth of field...all the essentials of good photography seem simple when they are explained in terms you can understand. Visit http://www.naturesimage.com.au and check out Andrew Goodall's ebook "Photography in Plain English" to discover your own talent for photography. While you are there, subscribe to the online newsletter for even more tips...it's free!

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