Focal Length in Digital Camera Lenses
The first thing you'll have to keep in mind when checking out digital camera lenses is what is alternatively known as either focal-length multiplier or focal-length magnification. This is the conversion that results from the APS-size sensor used on a digital SLR. In other words, your digital SLR lens is going to act in a way larger than it actually is.
The conversion is about 1.5 to 1.6, which means that a 50 mm lens really gives you an angle of view compatible to a traditional 75 mm lens. For instance, 200 mm would be 300 mm. However, it's important to note that this only accounts for the angle of view, and doesn't actually change the optics principles or distortion of a particular lens sense or style.
Look Out for Apochromatic Correction
digital camera lens
A few other lens features or options to keep in mind include apochromatic correction, image stabilization and digital only lenses. Starting with the latter, digital only lenses provide great value but won't be compatible with a traditional camera, or potentially future SLRs with 35 mm lenses. Examples of this include the Nikon DX.
Image stabilization will help you get better shots by counteracting camera shake or blur from slow shutter speeds, and apochromatic correction helps to improve image sharpness. Also note that while some lenses offer image stabilization, some camera bodies such as those from Olympus and Sony are designed to provide the stabilization effects.
Top Brands to Look For in Digital Camera Lenses
You'll certainly have a wide range to choose from, when it comes to brands. The most recognizable of the bunch undoubtedly are Canon digital camera lenses, which have a great reputation as being high quality lenses in keeping with Canon camera bodies, as well. In addition, you'll find some great choices from Olympus, Nikon, Tamron, Panasonic and a range of other manufacturers as well.
More customized solutions for a particular setting or style of photography may be found with some of these brands. You also may only be interested in using the same brand for the lens and the camera body. This often offers greater synergy and performance for your shots, but it isn't a necessity in most cases. It's entirely up to you whether or not you'd like to do this.
This has been just a simple starting guide for digital camera lenses. There is definitely more to consider, and of course you'll have to cross the bridge of how much money you need to end up spending as well. You will always be able to find a great match for your specific needs and your budgetary constraints, whatever they may be, but it's always better to purchase one versatile, high quality lens than needing to buy a range of more limited and lesser quality lenses.