Need info on lenses for DSLR cameras?
I got a Nikon D5000 about 6 months ago with an 18-55mm lens… Looking to upgrade to a bigger lens but know virtually nothing about the different ones out there… First off, what is the point of a lens such as a 50mm, like that have only one focal length? Also for all you more pro photographers out there, would you prefer, for instance, an 18-200mm or getting an 18-55mm and 55-200mm separately? And would I need one as big as up to 300+ or is 200 or so good? Any info about these lenses is greatly appreciated.
Added (1). Let me add that I'm an amateur but super enthusiastic about going pro. Mostly interested in photographing people, especially kids & babies. Also, I meant to ask what some of the letters mean in the lens descriptions such as AF-S Nikkor 50mm f/1.8G.AF is auto focus, correct? What about the -S? The f/? And the G? Also some are VR (vibration reduction) and some are not? When would the difference be noticeable? What about ED or just D @ the end of a description? DX? Thanks again, have already gotten all super awesome answers!
Added (2). Oh and what is the difference between 50mm f/1.8 and 50mm f/1.4? I notice the 1.4 is pricier…
Ok, first off - fixed focal-length lenses will always be better visual quality than zoom lenses from the same range. They'll almost always have a lower minimum f.stop too, making them a bit more adaptable to differing light conditions. They're generally also less prone to faults, as there are fewer moving parts. When it comes to zoom lenses, it's generally safe to assume that the longer the zoom range, the poorer the optic quality, so if you're going for zoom lenses you're better off figuring out how you're likely to use the camera, and chose a range accordingly. The 50mm lens is sorta the default mid-point - anything below 50mm is wide-angle (or macro at the bottom of the range), and anything above 50mm is telephoto (although really only above 100mm would usually be considered true telephoto). Personally, I actually tend to do most of my shooting with a standard 50mm, but what suits you will depend on what you're shooting.
You do have an option, the 55-300 mm may just fit your needs.
As you said, the single lens solution of the 18-200 mm is one way to go or if you keep your 18-55 mm lens, the new 28-300 mm may be a good option
You can find out more about each lens here
As has already been stated, prime lenses (ie those with a fixed focal length such as 50mm) offer better image quality, are faster (wider apertures) and are, in my opinion, better for improving technique because you 'zoom with your feet' and learn more about composition rather than use the lens to zoom.
As for what lens is suitable for you? Well it would help if you stated what type of photography you are intending to use it for. What exactly do you mean by a "bigger" lens? I could certainly recommend a few but lenses that involve portrait, landscape, sports, street, macro photography etc differ immensely.