Lightroom: Lens correction slider for the perspective options

Hi Ka Wang Wu,

Well, that's what the manual sliders in "Lens Correction" are for, don't you think ?

They are not so hard to figure out, but you need to work them in good order.

Distortion will fix barrel / cushion distortion. Chances are you do not need to touch it,  if you enable lens profile correction, it's done already.
Vertical is the most important, as it will fix vertical alignment. Going left with the slider makes them go \ | /, going right makes them go / | \, fiddle until they are all parallel | | |
Horizontal works the same, only with horizontal lines.
Rotate is often needed, when verticals are aligned, they may still not be parallel to your photo sides, or you horizon might still be off.
Scale is nothing but some kind of "zoom in - zoom out", I never use it, i guess someone has a use for that too, but I can't see one for myself.
Aspect will  correct (if needed) the vertical to horizontal distance ratio, most of the time this is not needed, but there are cases where an automatic upright correction needs to be corrected.

So skip distortion unless you actually have distortion, and use the sliders one by one from top to bottom. Most times only Vertical and Rotate are needed.

Mind, if  you have both horizontal and vertical corrections applied, chances are your viewpoint was off centre and you cannot expect to obtain perfect rectangular shapes, but you can go a long way.