Distortion vs. perspective corrections

I am a little bit confused by the different geometry corrections available in DxO Photolab 4 and ViewPoint 3. In Photolab there is the distortion correction that is unique for each lens (camera + lens combination?), if you have the appropriate optical module installed. How does this differ from the automatic Perspective correction that is available if you use ViewPoint as a plug-in? I can see that the results are different, but I would like to know what the principal difference is in order to understand what I am doing better. Should, for instance, both corrections be applied simultaneously, and why?

To this may be added the following question. When Viewpoint is installed there is both a slider for Distortion and a slider for Perspective in the right-side column under Geometry. Under Distortion I can choose the option “Auto with DxO Optics module”. I have been assuming that this is the same correction that is automatically applied through the Photolab presets if optical corrections are on. Is this right, or is this an additional correction made available by Viewpoint? What is confusing here is that Viewpoint is so well integrated into Photolab, that you cannot determine what it adds to the system.

I hope i didn’t ask too many questions now …

The Distortion tool uses profiles to correct for lens issues like barrel distortion and pin cushioning. The Perspective tool is completely different. It fixes perspective issue caused by a lens placement relative to the subject. The link is to the DXO promotion page for Viewpoint. Perhaps it will help you. Viewpoint primarily adds Perspective, the Miniature effect and Volume Deformation. Everything else is already in PhotoLab.



A tutorial for the functions of ViewPoint: