The creation of a distortion-free vertical panorama uses the Adaptive Wide Angle filter to perfect the stitched image.
I have avoided using the ‘Adobe Photomerge’ feature so that I can intercept the stitching process at the alignment stage to specify which image (with the least distortion) Photoshop should respect in terms of its perspective.
The resulting image is then enhanced using the luminance-preset available from the e-Store on this website. This Preset allows you to uses the Black & White adjustment layer set to Luminosity mode. The combination of adjustment layer and preset gives you Luminace control over colours as you would see in Adobe Camera Raw