I don’t feel like writing today, so let’s just celebrate the 50mm f/1.8 lens. It costs about a hundred bucks, but you can do a lot with it.
Grab it and shoot. The 50 f/1.8 is sharp, focuses fairly close, and loves low light. That makes it a perfect lens to keep on the camera for opportunistic shooting.
Traveling? The 50 is small and lightweight - easy to carry around all day.
Shooting portraits? On a cropped sensor like my Nikon D300, the 50's angle of view is similar to a 75mm lens on a 35mm camera. This provides a nice working distance for 3/4 portraits.
Out on the town? You'll need a very expensive camera to work in low light - or a hundred dollar 50mm f/1.8.
Need depth of field control? Working under overcast skies? 50 to the rescue.
Grab shot opportunity? Sure, you could work with a standard zoom. Or you could take a couple of steps forward or backward with the 50.
Did I mention low light? Well, it's worth mentioning again.
With a fixed focal length lens, there's no second guessing the framing while you fiddle with the zoom ring. You move to where the composition looks right and you take the picture.
Modern zooms are fantastic, but a fixed focal length lens makes you think about composition more. That's a good thing.