Most kit lenses give focal length ranges of 28-70mm in 35mm terms, and at f/3.5 aperture at the wide end, and most give considerable barrel distortion which is annoying.
High end zoom lenses may offer f/2.8 (or in the case of Olympus ZD 14-35mm pro lens, f/2.0)
But there are times when you need a wide angle lens of 24mm field of view and wide aperture for low light hand held shots of interiors where tripods are not allowed or your did not bring one, or for that matter at dusk or even at night.
Professional photographers wanting relatively shallow DOF or low light capabilities at 24mm focal length generally choose a full frame dSLR and combine it with a pro-level 24mm f/1.4 lens.
This combination will give better low light perfromance and shallow DOF than is possible on cropped sensor cameras, but the kit is BIG, HEAVY, EXPENSIVE (~$2500 for the lens alone) and there is no image stabilisation available unless you choose a Sony option.
Those with cropped sensor dSLRs such as Canon APS-C or Nikon DX cameras, must settle with an expensive 14mm f/2.8 lens which gives a touch wider field of view and much greater DOF.
As mentioned above, if you have an Olympus dSLR Four Thirds camera, you can buy the big, expensive ZD 14-35mm f/2.0 lens and this will also have image stabilisation courtesy of the camera body.
If you buy a Sony NEX or Samsung NX, you will have to settle with a 16mm f/2.8 lens and no image stabilisation.
This lens is not exactly cheap at just over $700 in the US, but it is a high end optic with a very nice manual focus capability better than most mirrorless lenses.
It will give potentially better low light performance than any cropped sensor dSLR, Sony NEX, Samsung NX system as the f/2.0 aperture allows 1 stop lower ISO to be used which should neutralise any high ISO benefit of the larger sensors, while the image stabilisation provides potential for slower shutter speeds when you don’t have a tripod with you and the subject is not moving.
The Sony E 16mm f/2.8 is a cheap ($290), consumer pancake style lens with slower AF, not-so-nice manual focus than the enthusiast level Olympus 12mm f/2.0, while having lots of CA and very poor sharpness towards the edges (you need f/8 to get reasonable edge sharpness!) – it is certainly no match for the Olympus lens (although the Sony has better RAW distortion levels) – see here. One can usually easily correct distortion but lousy sharpness is not easily resolved and the Sony lens distortion is a weird, wave-type pincushion distortion when straight lines are near the image edges, and this type is hard to correct in standard image correction software. Sony NEX landscape or architectural photographers will have to wait until Sony produce a better lens.
Of course, this Olympus m.ZD 12mm f/2.0 lens can be used on any Micro Four Thirds camera including the Panasonic GH-2, and G-3 but the Panasonic cameras do not have image stabilisation built in and presumably will not auto-correct the barrel distortion as do Olympus cameras.
None of the above will match the shallower DOF capability of a 24mm f/1.4 on a full frame dSLR, as the cropped sensor dSLR f/2.8 or the Olympus f/2.0 lenses, will only give DOF comparable to f/4 on a full frame dSLR, nor will they match the low light capability of f/1.4 aperture with good high ISO of a full frame sensor for moving subjects.
Nevertheless, the lovely compact size and relative affordability of the Micro Four Thirds option makes this a compelling choice for many people – I for one intend to buy one as I can’t take my Canon 1D dSLR, a 24mm f/1.4 lens and other lenses on international travel as they are just too big, heavy and expensive.