01-19-2020, 05:52 PM
I doubt that any of us, you included, BC, could tell the difference between -1.28%, -1.35% or -1.94% distortion except in direct comparison - and even then: all these testing sites check one copy per lens. It would be sheer luck if two sites found exactly the same value of distortion.
Also, the test charts are in a distance of 25-50 × FL. In the Panasonic case: 25-50 cm away from the sensor. I reckon no one does architecture in this distance? For some optical designs like the ones with floating elements and inner focusing, distortion can depend on FL and distance setting. Less than 2% distortion for a wide-angle already counts as good in my book. For a 10 mm zoom even more so.
Also, the test charts are in a distance of 25-50 × FL. In the Panasonic case: 25-50 cm away from the sensor. I reckon no one does architecture in this distance? For some optical designs like the ones with floating elements and inner focusing, distortion can depend on FL and distance setting. Less than 2% distortion for a wide-angle already counts as good in my book. For a 10 mm zoom even more so.