Originally Posted by bushwick1234
Thanks for the suggestions, but I returned the lens already. And the camera as well.
DXO is not for free, right? And there are many lenses that don't have distortion at all. Isn't it a paradox to have to purchase extra software to correct lens design flaws? To me the heavy distortion displayed by this lens is a serious flaw.
No, because those corrections have nothing to do with a 'flaw' in the lens. That is the reality of all wide angle lenses, even an optically 'perfect' lens will have perspective and volume deformations.
Optical lens quality distortions are combinations of barrel and pincushion distortions. Your image isn't showing that. Your image is showing perspective distortion which was caused because you didn't have the lens level and square with your subject. You were shooting with the camera pointing down, the top of your image is closer to the sensor than the bottom of your image. You would get that same distortion with any lens of that focal length if it was held at the same angle.
As an easy example of this take out the camera on your phone. Hold the camera up to a framed picture on your wall, tilt the camera top torward/away from the frame and watch how that changes the perspective distortion on the screen. That is what happened in your picture.
You can correct that (to a point) in LR but you needed to use the transform controls. The real solution is of course to understand where the distortion came from so you can avoid it next time. A different camera + lens won't solve this.