I've been looking at a 10-22mm lens for my Canon T2i. I've also come across some other "wide angle" lenses, like the Sigma 24-70mm F2.8.

I don't understand how a wide angle lens can have such high numbers. The kit lens is 18-55mm; 18 is lower than 24 — so does that mean the kit lens is a "wide angle lens?

  • 1
    "wide angle" is not a technical term, it has no precise definition - you could ask how can a Humvee and the space shuttle transporter both be "wide" vehicles
    – Matt Grum
    Sep 2, 2011 at 11:41
  • @Matt Grum — that's easy. They're both wider than 8' 6". :)
    – mattdm
    Sep 2, 2011 at 16:46

3 Answers 3


Traditionally, lenses wider than 24mm on full-frame are "ultra-wide". On a smaller-sensor Canon DSLR, a 15mm lens provides that same field of view (16mm on Nikon, Pentax, or Sony; 12mm on Olympus/Panasonic). So on an APS-C camera, a 20mm lens would be "wide" but not "ultra-wide" — but with the increased field of view of full frame, that would fall under ultra-wide.

On full frame, a 35mm lens is wide angle (but not ultra-wide); that same lens would be "normal" on an APS-C camera.

In either case, yes, the 18-55mm kit lens is a wide-angle lens. On a crop-factor DSLR, that nicely covers a reasonably wide angle, through normal, up to a moderate "portrait-length" telephoto.

(On some systems, some lenses designed for APS-C cameras won't work at all on full frame. Or, they'll work but with poor performance in the corners — and on Nikon, for example, this is compensated-for by automatically cropping-out the edges when a designed-for-APS-C lens is attached. But it's pretty much universal that full-frame lenses will work on APS-C.)

  • So what you're saying is that if I have a 24mm lens that works on both cameras, the camera will determine if the lens is "wide angle" or not - is that right? Any thoughts on the best entry-level ultra wide for an APS-C ?
    – cwd
    Sep 2, 2011 at 2:19
  • 2
    Well, technically, a 24mm lens is wide angle on both APS-C and full-frame — I'm not sure if there's a perfectly agreed-upon upper limit to "wide angle", but 35mm is a traditional wide angle lens for full frame, and 24mm on APS-C is right around that. But yeah, the camera format (sensor size) determines whether a given focal length is wide angle or not.
    – mattdm
    Sep 2, 2011 at 2:22
  • As for the recommendation — the kit lens (for any brand) is almost certainly the best value in a basic entry-level wide angle lens. But if you want to go wider than that, you'll need something else, and I don't have a lot of expertise there.
    – mattdm
    Sep 2, 2011 at 2:23
  • If I see through the viewfinder with a 50mm-F1.8 on my APS-C camera, things appear to have no magnification (1:1). So on crop, everything below 50mm would be wide I guess
    – rompetroll
    Dec 11, 2012 at 9:42
  • 1
    @rompetroll See this on 50mm lenses and viewfinder magnification. In general, no: the accepted definition of wide/normal/long has nothing to do with that.
    – mattdm
    Dec 11, 2012 at 11:46

All of the lenses you mentioned are wide angle lenses; the distinction is that there are degrees of wide-angle. On your T2i, that 24–70mm lens at 24mm will be a moderate wide angle. The 10–22mm will be an ultra-wide (maybe ultra-ultra-wide?) at 10mm, and go to a more moderate wide angle at 22mm.

Mike Johnston wrote an amusing but opinionated article called Uses and Applications of 35mm lenses that attempts to break down the various categories of wide angle lenses. The focal lengths are for a full-frame camera, but you'll get the idea.

If you're looking to go really wide, Ken Rockwell’s article How to Use Ultra-Wide Lenses is a strong introduction to the significant challenges and rewards that you'll see from using ultra-wide lenses.

  • 1
    +1 — Ken Rockwell at his best. And the Mike Johnston article is quite funny (but I'll bet he wouldn't write that today!).
    – mattdm
    Sep 2, 2011 at 4:11

"Wide", "normal", and "telephoto" depend not just on the focal length, but on the format size as well. In the full-frame (35mm) world, any focal length shorter than 35mm or so counts as "wide angle" in that it captures a wider field of view than a "normal" 50mm lens (which roughly reproduces the field of view we see with our eyes).

In the large-format world (4" x 5"), a 50mm focal length is on the wide to ultra-wide side. In the APS-C world, that same focal length is slightly telephoto, and 35mm is "normal" (or close to it).

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