Sony E Mount Lens Optical Bench Tests by Lensrentals.

Lensrentals tested a few E-mount lenses and confirms that Sony has some issues on delivering consistent quality on their lenses. There are larger copy-to-copy variations than with Nikon and Canon lenses.

Mostly we are just starting with FE lens testing. Over the next few weeks, we should get a good handle on how the Sony lenses compare to each other.
I think there’s no question we’ve seen support for what a lot of people are claiming: the [shoplink 41854 ebay]35mm f/1.4 ZA lens[/shoplink] is very likely to have some tilt with one corner or side out of the plane of focus. Depending on what you photograph this may make no difference to you, or may be a huge issue. But I doubt sending copy after copy back is going to make much difference (you may trade a soft right upper corner for a slightly soft left side, etc.). We’ve taken a couple of these apart and there’s not a ton of optical adjustments that can be made: there are a set of shims behind the front group that can be modified a bit, but it’s a crude and very time-consuming adjustment, so I don’t think it’s generally going to be something that can be fixed.
The [shoplink 41856 ebay]55mm f/1.8[/shoplink] is really a good lens, very sharp and consistently made. The [shoplink 41855 ebay]90 mm f/2.8[/shoplink] is a decent lens, reasonably sharp, but there seems to be a fair bit of copy-to-copy variation in overall sharpness.
All that being said, these lenses may look better on-camera than on the optical bench because there seems to be at least some modification of files as the raw is written. We’ll get a better handle on that as we test more lenses.

In short: Sony really has to improve the quality control on the production chain.