Luminous Landscape Forum

Raw & Post Processing, Printing => Digital Image Processing => Topic started by: Guillermo Luijk on April 27, 2010, 03:07:35 pm

Title: In PS Lens correction: is distort/perspective/rotation performed in a single step?
Post by: Guillermo Luijk on April 27, 2010, 03:07:35 pm

Does anyone (Madmanchan?) know by certain if the geometric corrections in the Photoshop 'Lens correction' tool (Distortion, Perspective and Rotation) are perfomed in a single math operation? so that quality loss is kept to a minimum.

(http://img91.imageshack.us/img91/65/27740083.gif)

I don't see any reason not to do it that way, but would like to be sure from some informed source.

Regards

PS: BTW I wonder by the vignet correction is applied after all the other operations (Distortion, Perspective and Rotation), this is nonsense since vigneting is an optical flaw and hence has the centre of symmetry in the middle point of the original image.

Title: In PS Lens correction: is distort/perspective/rotation performed in a single step?
Post by: madmanchan on April 27, 2010, 10:15:37 pm

Hi Guillermo, unfortunately I don't know the answer with regards to the PS Lens Correction plug-in. (For Camera Raw and Lightroom, the answer is yes, only a single image resampling step is performed, and the lens vignette compensation is done in the logical manner, i.e., prior to executing the warp transform.)

Title: In PS Lens correction: is distort/perspective/rotation performed in a single step?
Post by: Guillermo Luijk on April 28, 2010, 02:45:04 pm

Thanks for your reply Eric, I guess PS also performs a single step (or hope so).

Cheers