Photozone.de just published their review of Sony’s new stabilized 50mm f/1.8 lens, available for their NEX mirrorless system. The thing that makes this lens special is the fact that it combines a big aperture with optical stabilization. In fact, to my knowledge this is the fastest (lowest f-number) stabilized system lens (of any focal length) ever built!
Large apertures are great in low light situations. It enables you to gather more light, thereby letting you use a lower ISO value or faster shutter speed. Lower ISO means less image noise and better colours.
The “problem” with traditional 50mm primes (like those of Canon, Nikon) is that when you’re shooting hand-held you have to use a fast shutter speed (e.g. < 1/80) because they lack stabilization. If you had stabilization and were shooting a static subject you could probably have gone down to 1/10 and have used an ISO value 8 times lower.
The large f/1.8 aperture gives about 3 stops extra light compared to a 18-55 f/3.5-5.6 “kit zoom”, but you lose the 3-stop advantage you would have gotten with the kit zoom’s image stabilization. Since the advantages cancel out you instead have to use the same ISO value for either lens at its minimum usable hand-held shutter speed. But with the new Sony you can choose to apply that large aperture either for low ISO (useful for static subjects) or for fast shutter speeds (useful for moving subjects). In one word: versatility!
Why you want a large aperture:
fast shutter speed (less motion blurring) and shallow depth of field
The advantages of a “nifty fifty” go further than being able to use fast shutter speeds. These lenses are almost always sharp (at smaller apertures), small, light, and can render backgrounds with beautiful shallow depth of field blurring, known as “bokeh”. By also being affordable (often < $300) you will find one in the bag, or on the camera, of every serious photographer.
For the reasons stated above a “nifty fifty” works nicely as a portrait lens on cropped sensor DSLRs. For a great example, see this photo by Ana Santos :
An example of the great results you can get with a 50mm f/1.8
(such great bokeh is unachievable with a 18-55mm kit lens).
Reading the review we see that this new Sony lens has nothing to be ashamed of, and at $300 (available for pre-order at B&H) it is good value for money, too! It is not the sharpest lens at large apertures, but renders beautiful out-of-focus background “bokeh”. If you want sharpness you just have to stop it down. And, it is stabilized!
Conclusion: a very harmonious offering. The unique double advantages of a classical fast 50mm prime and image stabilization. Sony NEX users can count themselves privileged.