I purchased this at B&H, the supporting images can be seen on my review at that site.
I tested this lens on the Sony A7r. It is soft at 24 and 35mm starting at 60% of the way out towards the edge. I compared it to my current system, the Canon EF-S 15-85mm f4-5.6 IS on Canon Rebel 550D. I photographed a brick wall at a variety of focal lengths and f-stops, I’ll only go into detail on one set, take at 24mm f8 on the Sony, and the equivalent focal length on the cropped sensor of 15mm f8. Both sets were taken at ISO 200 and 1/250. These parameters eliminate depth of field and “shutter shake” considerations. I used Photoshop to “up-scale” the 16Meg Canon file to the 36meg that the Sony file contains. The 100% crop images may be seen on the B&H review of this lens, since I could not post them here. The Sony is perhaps a bit sharper at the center. By 40- to 60% of the way to the edge along the horizontal they are equal. At 70% the Canon is sharper and the difference increases as one goes closer to the edge. The story is similar at 35mm. The Sony is sharp across the field at 50mm, but at 70mm some softness creeps in to within 10% of the edge.
The positives are the lens seems well build, is compact. I like many aspects of the A7r. Judging from other reviews, the Sony prime lenses do much better. Ultimately my reason for going from a cropped sensor to a full frame camera is to improve image quality. Small and light is a tremendous factor for me. However, without an improvement in what is my most used focal length range, I concluded that is pre-mature for me to jump ship to the Sony FE system and returned the camera and lens to B&H. I am hoping future lens offerings will cause me to reconsider.