These are my final tests (for now) of the Sony NEX-7. See also Part 1 and Part 2. To wrap this up, I rented two Sony E-mount lenses: a second 18-35mm f/3.5-5.6 and a 18-200mm f/3.5-6.3. The reason for getting a second 18-55mm was to determine whether the disappointing performance was due to my particular copy or shows up in other copies.
As for the 18-55mm, my copy of the lens is in fact slightly sharper at 55mm and f/5.6. At f/8, both mine and the rental lens were equally sharp. As mentioned in the previous tests, this is really a “keep it at f/8″ lens if you want the sharpest possible results.
Comparing the 18-55mm to the 18-200mm was also interesting. At 55mm f/5.6 the longer lens was sharper in the center but noticeably softer in the corners. At 55mm f/8 they were equally sharp in the center but the longer lens was again softer in the corners. And comparing the 18-200mm to itself wide open at 55mm (f/5.6) and 200mm (f/6.3), it was quite soft at the longest focal length (center and corners) as well as showing quite a bit of chromatic aberration in the corners at 200mm.
While I still like the camera quite a bit, I’m really looking forward to some better zoom lenses. I like the 11x range of the 18-200mm, but since it’s about the same size/weight as the Nikon 18-200mm f/3.5-5.6, there’s not much advantage over just using the Nikon lens on my D7000. The Nikon body is larger, but with a big lens, the difference isn’t as significant. With the smaller 18-55mm, you take more advantage of the NEX-7′s diminutive body. For now, at least, I’m going to stick to the smaller lenses for the NEX-7 and just take my big Nikons (D700, D3s) with the superior glass when compactness doesn’t matter.
FYI: I’ve heard the Sony 50mm f/1.8 ($300) is supposedly a better lens than these zooms, and since it’s obviously much faster, I may give that one a try. I like the idea of a 75mm full-frame equivalent lens.