I received a Sony NEX-6 body (no-lens) over the holidays this year and I am looking to find the right lens to match. I am searching for the most versatile lens available for this camera. In other words; if you could only have one lens for this camera what would it be? As I plan to travel with this camera I want to invest in a solid piece of glass that can suit a range of subjects and settings - I want to keep my pack as light as possible.
The most versatile Sony E mount lens that is both light and compact, other than for low light use, is either one of the two kit lenses sold with various NEX models: The E 16-50mm f/3.5-5.6 OSS PZ or the E 18-55mm f/3.5-5.6. The 16-50 is very lightweight and compact when stored, so ideally fits your use case as a light travel camera. It may not meet your expectations in terms of image quality.
Neither of the kit zooms will offer the image quality or the low light performance of a prime lens. With primes you get better image quality and superior low light performance, but you give up a lot of versatility in the exchange.
There is a lot of historical precedent by well respected photographers who liked to travel light that combined 35mm prime lenses with Leica 35mm rangefinders. With the sensor size of the NEX-6, the equivalent FoV would be at 23.3mm, so the 24mm lens would be equivalent. Since the shooting distance would need to be the same to similarly frame the same subject with either camera/lens combination, the perspective yielded by each would also be the same.
Here is a three way comparison between the E 16-50mm f/3.5-5.6 OSS PZ, the E 35mm f/1.8, and the Sony Carl Zeiss Sonnar T* E 24mm F1.8 ZA. Click 'Measurements-->sharpness-->Profiles' to see each lens' sharpness compared. You can click various focal lengths and apertures to see those results. In terms of sharpness both primes are as sharp at f/1.8 as the zoom is wide open at f/4.5 (25mm) or f/5.6 (35mm). The 16-50mm zoom lens distorts slightly more (barrel) than the Zeiss (pincusion) at 24mm, and less than the Sony 35mm f/1.8 at 35mm. In terms of vignetting, at 24mm the Zeiss equals the 16-50 zoom (f/4.5) somewhere just past f/2. The Sony 35mm f/1.8 vignettes the same at f/4 as the 16-35 zoom does at 35mm and wide open at f/5.6. There's not a lot of difference between the 16-35 zoom at 25mm and the Zeiss in terms of CA, and the 16-35 zoom at 35mm and the Sony 35mmf/1.8 show very little CA at all. Unfortunately, DxO Mark has not tested the Sony E 18-55mm f/3.5-5.6 OSS PZ so we can't compare the two zooms using DxO Mark. The new Sony Zeiss 16-70mm f/4 might also be a lens to consider, but it is fairly new and the major review sites, such as DxO Mark, have yet to list it in their databases. This review gives mixed results on the Sony Zeiss 16-70mm f/4 and the reviewer ultimately thinks the price is too high for the image quality it gives.
For further reading, this blog entry at The Wirecutter, runs down a list of lenses available for the NEX system in the order the writer recommends acquiring them. It succinctly covers the strengths and weaknesses of each. It does assume either the 18-55 or 16-50 zoom came with the camera, so it doesn't discuss them much. A couple of very new lenses aren't covered in depth, but updates since the article was originally written in early 2013 are included. There are also 33 links in the footnotes to other reviews of many of the lenses discussed. If you're more the type that just wants to see a list without as much commentary, this one at Sony Alpha Lab runs them down. (Sony Alfa Labs is a review site that is not formally affiliated with Sony Corporation.) For a completely bare bones list with no commentary, there is this list at wikipedia.
"Versatility" is one of those terms that means different things to different photographers.
Most people take photos to record important people, places, and events. Family, vacations, homes and pets – I wish I had more of these photos myself. Versatility in this case usually means "more zoom" (this is the number one thing people with 18-55mm kit lenses ask me for in the store where I work) so that anything from wide angles to long shots can be covered with one lens. So for taking photos of the kids on the sidelines to playing at the far end of the field, or taking in an entire architectural facade in one shot and a detail of the statuary in the next, some sort of superzoom is a good choice. Sony has made a number of 18-200mm lenses in E-mount, and others make them as well, so pick the one that suits your budget.
Superzooms are larger than a shorter-ranged zoom lens, but smaller than the two lenses that combine to cover the same range. While they're not great in low light, they're not really any worse than other consumer zooms that have the typical f/3.5-5.6 aperture range. Just make sure you get one with some kind of built-in image stabilization, and accept that there are some image-quality compromises that need to be made to have that long a zoom range.
Other people will use cameras to produce photos for their own sake. Expressive, aesthetic, artistic – the intended audience for these photos may have no connection to the subject matter at all. "Versatility" in this context means being able to take the kind of photo that the photographer wants, which is fairly narrowly defined, in under diverse conditions. This is where fast prime lenses, or brighter zoom lenses, become important.
This is a tough lens type to recommend because individual tastes vary so much. A friend and I go out to photograph together with the exact same camera model, but we don't have a single focal length in common. So starting with a standard zoom in the 17-55mm-ish range, ideally with a fast aperture, will provide a lot of options and perhaps some insight into whether further specialization is needed.
But this division that I've outlined is by no means exclusive or definitive: I know a fine-art photographer who produces wonderful images, and has been published in a magazine that I read for artistic inspiration, using an off-brand superzoom and a camera that's three generations old. Use whatever you choose however you wish, and don't let anyone tell you that their way is the only way of doing something.
The most versatile lens I can think of is a fixed aperture std zoom like 17-50 F2,8. After I got one I rarely use else. But I dont think they make those for sony nex. But they do make them for sony alpha and you can get an adapter for emount LA-EA2.
I've used 28mm prime as a workaround on travels, and it is not a bad compromise. But people pics look distorted. So the 24mm lens you are looking at is certainly a good choice, but versatile not so much. You are making sacrifices by choosing a wide prime. You could pair it with a good 50mm, though.
If you are travelling then the best option is probably the Sony E 18-200mm. It has the usual foibles of all superzooms - barrel distortion at the wide end, pincushion distortion at the telephoto end, mediocre resolution wide open - but when you're travelling you want to have as wide a range as possible.
According to The Wire Cutter, the 18-200 at least equals the 55-210mm zoom. This is better than most superzooms, which tend to be slightly worse than a dedicated telephoto zoom for their camera system.
(Note that some of the more critical reviews were done on a NEX-7, which is much more demanding on lenses than the 16MP sensor used on most other NEX cameras)
The other possibility when travelling of course is to take a small number of light, good-quality prime lenses (e.g. the DA 15, DA 35 and DA 70 'Limited' lenses on Pentax). Unfortunately the NEX system is somewhat lacking in this regard - the 16mm pancake actually has lower image quality than the 16-50 zoom, and there are no NEX primes longer than 50mm. The E 35mm is great, but a single standard prime lens doesn't fit most people's definition of 'versatile' and probably won't fit yours.