The perennial advice for new SLR owners is to buy a “nifty fifty” lens: an inexpensive (but optically very good) lens with a fixed focal length of 50 mm. Most camera makers offer one of these for $100–150. They don’t zoom, but when you mount them on a full-frame camera they provide roughly the same field of view as the human eye, making them useful for many different styles of photography.

The operative phrase there, though, is “on a full-frame camera.” When you use a 50 mm lens on a crop-frame APS-C camera, the effective focal length is more like 80 mm in full-frame terms.1 APS-C cameras dominate the lower end of the SLR market, so the first-time buyer who’s being advised to buy a nifty fifty is probably going to be mounting it on a crop-frame camera.

That combination is much less versatile. To my taste it’s too “zoomed in” to be a general-purpose or walkaround lens, and while it’s a good focal length for portraits you have to be at least a couple of yards2 from your subject or else your composition will feel cramped. Fixed-focal-length (“prime”) lenses may have better optical quality than the zoom you buy with your camera, but that’s irrelevant if the lens has too narrow a field of view for you to get the photos you want.

If you’re buying your first SLR and you’re considering a prime lens to go with it, you might want to spend a couple of weeks shooting with the kit zoom first. These have ranges like 18–55 mm, so you can just set it on 50 mm and pretend it’s stuck there. Is that a comfortable focal length for you? If yes, great! My nifty fifty became one of my most-used lenses once I learned what it was good for (and what it wasn’t). If you find that a different focal length better suits your style, though, you might be glad you didn’t unnecessarily constrain yourself to 50 mm right off the bat.3

  1. The “effective focal length” can be found by multiplying 50 mm by the crop factor of your camera. For APS-C cameras these factors range from 1.52 to 1.7.↩︎

  2. A couple of meters.↩︎

  3. The obvious solution here seems to be to buy a prime lens in the 28–32 mm range, which would give you a field of view equivalent to 50 mm on full-frame. That’s true; there just aren’t any lenses in that category that are quite as good a value as the nifty fifty. (Not in the Canon system, anyway, as far as I know.)↩︎