The Tamron 150-500mm f/5-6.7 Di III VC VXD is a very capable super-tele zoom lens. Its center quality is certainly good enough for the purpose it is meant for. In the lower focal length range, it touches excellent quality in the center and it's still very good at 500mm. The outer image field is a bit of a mixed bag. At 150mm, the sharpness is very good but it suffers from rather heavy field curvature mostly visible at close to medium focus distances. The field curvature is gone at 250mm and the borders/corners are pretty good until 400mm. They do soften at 500mm, though. That being said - keep in mind that the border/corner quality is mostly irrelevant with such a lens. The lateral CAs are well controlled and eliminated via auto-correction anyway. The lens also shows fairly high image distortion in RAW files (only). The vignetting characteristic is a tad high in RAW mode but no issue after correction, of course. The bokeh has two aspects. The general blur is actually pretty smooth, whereas out-of-focus highlights can be rather nervous.

The build quality left a positive impression despite the extensive use of plastics. It feels solid and there is no wobbling whatsoever, even when extended to 500mm. The small focus ring isn't the best in the business but the zoom ring is surprisingly smooth despite the heavy weight of the inner lens tube. We liked the push/pull zoom lock mechanism - which is also needed due to the extending zoom design here. The AF speed depends heavily on the used Sony camera. It's not a speed demon on older bodies but if you own the latest and greatest, the AF is impressively fast and noiseless. The VC image stabilizer gave us about three f-stops which is decent enough given the long focal length.

In our book, the primary differentiator of the Tamron 150-500mm f/5-6.7 Di III VC VXD is the compact size. It is much more backpack-friendly than the big Sony FE 200-600mm f/5.6-6.3 G OSS. Some users will also appreciate the shorter minimum focal length, which is certainly making it somewhat more versatile. However, the king (the Sony lens) isn't dead yet.