... Because unfortunately seem Sony skills regarding design and optical design of not being able to keep up cameras with the outstanding quality of the sensors of the NEX. The 18-15mm lens has unfortunately all weaknesses that you like to take in conjunction with Kitobjektiven: It recorded particularly in the wide-angle range greatly, has significant vignetting at open aperture and, unfortunately, strong chromatic aberrations. Some of it can be improved in the post, but the strong edge blurring are no longer correctable and Fade on stop 8 or 11 provides for the recording not necessarily for a sharp image up to the image corners.
That there is another way, you can see 18-105mm lens, the sensor size has also for APS-C expected and is also heavily trimmed to price savings, but with almost twice as large zoom range to the edge much sharper than they look, for example the Nikon records , Image Stabilizer has it. Even the also projected for APS-C sensors kit lens mirrorless Samsung NX 100 is much sharper, while even smaller (but without stabilizer) as this Sony 18-55mm optics.