Choosing your lenses
Choosing the right glass to put in front of your sensor is a critical part of any system kit. Most professionals will tell you that it is 'all about the lens,' and in my opinion they are not wrong. A good quality lens makes all the difference. Do however bear in mind that certain lenses are limited to certain systems. Although converters are available in most situations, the cheaper ones often inhibit some basic functionality (i.e. autofocus). Assuming you have settled on a system/brand already, here are some general tips for beginners on selecting some good lenses to cover all eventualities.
“Fast” in this context refers to a lens with a wide aperture. This means that the opening in the lens permits more light than narrower ones. In practical terms this means that you can record more light in a shorter time. Fast lenses are useful for lowlight situations, as well as creating more bokeh (out of focus blur) for when you want to isolate your subject. A good example of such a lens is sometimes called 'a nifty fifty.' At a focal length of 50mm on a full frame sensor and a maximum aperture of f/1.8 this is a good all-rounder lens and I thoughly recommend having one in your kit bag.
Details fascinate me, and having sufficient length to reach them is vital for the kind of photography that I want to do. As a result, having a dependable telephoto lens is very important. Standard zooms come in a variety of focal ranges. A typical standard telephoto zoom range is from 75-300mm which covers most requirements. In the past, I have owned a 500mm super-telephoto prime, which was a joy to use, if a little impractical. Using a teleconverter for extra reach permits either 1.4x or 2x magnification on top of this, and utilises an effective crop of the central part of the frame, which is usually the sharpest. It is easy to spend a lot of money on telephoto and prime lenses, but until I have saved up enough for a professional modern prime ill make do with what I can...
There are some situations where you will have no hope of fitting everything in one frame. From mountainous vistas to street scenes and close quartered, cramped venues, having a wide angle lens is simply essential if you want to capture the scale of a place; be it large or small. The widest I have ever owned was a SIGMA 8-16mm, which - if anything, was a little too wide... I favour rectilinear wide-angles over fisheye lenses as barrel distortion is easier to correct in post processing. This is not to say however that fisheyes do not have their place in your kit bag. In fact they are a great deal of fun, and can be of great effect in landscape situations where you do not notice the bulbous pincushion distortions that are symptomatic of this kind of lens.
A mid-range zoom, or sometimes referred to as a 'travel' zoom is a fairly self explanatory addition. Around 40-150mm is a standard focal length range, and proves to be a very flexible when shooting from a car window or similar. I find my travel zoom spends most time on my camera when I am shooting portraits and street photography. This kind of lens grants you just enough zoom to isolate details, while still being able to manage when you find a broader subject.
Lots of people will tell you not to bother weighing down your already cumbersome kit bag with anything non-essential, but I believe there needs to be more fun in one's everyday. From reflex lenses to macro tubes, there is always something to interest me and fiddle about with. Some of the cheaper third-party lenses offer some zany focal lengths/distortions. Also, you may consider buying some vintage glass. Manual lenses teach you a huge amount about basic photography and are a joy to use. Such experimentation is good for creativity. Finding out how much fun you can have with different gear is half the joy of photography; in my view at least.