[See Update/Part 2]
In early May I managed to get my hands on a Sony NEX-7 camera with a couple of lenses. On May 15 I recorded a video review with Frederick Van Johnson on This Week in Photo. Ultimately, I decided this would be a great small, mirrorless camera to complement my huge Nikon D3s and its lenses, so last week I ordered one from Sony. I spent half of this past Saturday shooting with the NEX-7 and its kit lens, an 18-55mm f/3.5-5.6 (about 28-85mm full-frame equivalent). But when I got home and transfered the images, I was disappointed in their sharpness, pretty much uniformly. Did I get a bad copy of the lens? Was the camera just not as good as I though when I had a review copy? I decided to run some tests.
I’m just getting started, but here are the initial results. I started with the kit lens set to 35mm and f/5.6. (Wide open at 35mm is f/4 on this lens.) For comparison, I used an adaptor to mount a Nikon prime lens to the Sony body — an AF Nikkor 35mm f/2 D. Finally, I used the same lens on my Nikon D7000, which has an APS-C sensor, the same size as in the NEX-7. I used the lowest “normal” ISO on each body: 100 for the NEX-7 and 200 for the D7000. The results are below. Click the image to see it full-sized, 1:1.
My interpretation? The Nikon 35mm on the Sony NEX-7 body is sharper than Sony’s 18-55mm. No real surprise there. But both lenses are sharper on the NEX-7 than the prime on the Nikon D7000. Well, maybe that’s not really a surprise after all, since the D7000 is a 2+ year-old camera and uses an older Sony sensor that’s the same size as the NEX-7’s.
As for the final decision about the NEX-7, we’re not there. I still don’t have an explanation as to why this weekend’s images are so soft. Perhaps it’s because most were shot at 55mm. Or maybe it’s that I used ISO 200 most of the day. In any case, further tests are required to determine what’s going on here. Stay tuned.