Focal length Lenses
As always my intention is not saturaros of jargon and buzzwords ponéroslo gimmicky but easier, today I would like will simplify the concept of focal length as it is impossible to have a SLR camera (or consider buying one) without knowing what it means to the focal length.
What is the focal length of a lens or lens?
The focal length is one of the first things that stand out from a target when you buy, or buy an SLR digital camera and comes with it standard. Said in very plain words, the focal length becomes something like the scope of the target. The higher the value, the target will have more "zoom" to put it in some way.
How do you measure focal length?
The focal length is measured in millimeters. Therefore, for us to understand: a focal length of 70mm means that the lens is capable of zooming and be closer to the subject being photographed more than a lens with focal length of 18mm. And one of 200mm have even greater zoom capability.
That is, the more up the value, we zoom, the more we approach the subject, but the smaller the value of the focal length (24mm, 18mm, 14mm, and so we go down ...) less ability to zoom have the objective / lens and frame will change more.
After this brief explanation, see the objectives on the market.
Normally most of the objectives and existing lenses on sale for SLR cameras are objective with variable focal length range, I mean they are goals that normally have a focal length ranging from one value to another, for example, is very common to find focal length lenses from 18mm to 55mm or 55mm to 200mm. This means that the target is all that rank, and we can regulate it as we please, a very high rate if we are closer to 200mm zoom at a relatively distant target, or a very small value type 18mm if we want is a full frame capture a panoramic scene, landscape, etc.
There are also market fixed focal length lenses, but are made more for professional photographers.
Range "small or large?
My first camera was a Nikon D60, came standard with two goals: a 18-55mm and a 55-200mm. At first I was glad, because I thought "well I have an additional goal, but after a while I realized that photography hiking with 2 goals was not the most practical, since I had to change lenses every bit x time . I began to notice how there were people who had only one goal that went from 18 to 200mm, just one, and thought "how convenient! And do not have to walk by removing one and putting another every few minutes" .. So I determined to sell my two goals / lens and adding a little more money to buy a single goal that had the focal length range wider (18mm-200mm).
After some inquiries I changed my mind. Right now I still have two different objectives, and you'll wonder why? and I answer.
A goal is not just a tube with a series of lenses inside. Those lenses are made from the best possible way to get the best picture to the focal length was designed for the target. The wider the focal length, the harder it is to get a perfect shot. It is as if it were a subject of specialization, a 18mm-55mm lens is specialized in that range and therefore will draw better pictures than a 18mm-200mm lens.
The golden advice:
Buy a single focal length lens with a lot is not a terrible idea, and also has the advantage of facilitating the task of having everything on a single goal, but what really worries us is to get a good picture, and we are determined not spare no effort to get it, then it is best to have several lenses with focal lengths limited. Thus each target will have its use and time.