> On 28 May 2019, at 12:35, Torsten Bronger <bron...@physik.rwth-aachen.de> > wrote: > > Hallöchen! > > Iain Wood writes: > >> [...] >> >> Yes, true, but it still wouldn't do the fisheye-hemi >> thing. Whatever order they are applied in, the combination of >> perspective and lens correction can't achieve the transform >> necessary to do the fisheye-hemi effect. I'm fairly sure of >> this. Some sort of free transform is needed as per the photoshop >> guide in the original post. > > What Lensfun can achieve: > > - Vertical lines are straight and vertical > - Image cropping is minimal > - Horizon is straight even if not in the centre > > What is missing? >
Using this method gives un-natural distortion near the corners. Fish-eye hemi preserves shapes outside the central area. This is most obvious with faces. Fisheye-hemi allows fish-eye use for portraits which lensfun usually doesn't. I often photograph divers using a fisheye lens because I need to be close to make use of the limited light and poor visibility. If I run the images through fish-eye hemi then I get useable portraits. Other correction methods just don't seem to work no matter what I try. I can run the processing on some samples to demonstrate what I mean if you like, but the rockwell review and the fisheye-hemi page both cover it quite well. https://www.kenrockwell.com/tech/fisheye-hemi.htm <https://www.kenrockwell.com/tech/fisheye-hemi.htm> https://imadio.com/products/prodpage_hemi.aspx <https://imadio.com/products/prodpage_hemi.aspx> Iain ___________________________________________________________________________ darktable developer mailing list to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org
