I compared it with the full frame Tamron 28-200mm on A7r4A. Full Frame has better out focus as expected, but image quality is just as good. And the 18-300mm reach out as 450mm when it's still reasonable sharp. I also has a Sony 24-240mm which is not as good as both Tamron. Sony is always one f-stop smaller then Tamron at the same focal length. When Tamron is f4.0, sony will be f5.6. Tamron focus as fast and accurate, maybe Tamron is brighter. Tamron also lighter, cheaper.