Hey all I came across this blog which shows an alternative way to correct fisheye distortion that gives better results than the current rectilinear correction offered by the lens correction module in darktable: https://www.lonelyspeck.com/defish/
The blog describes a paid photoshop plugin called fisheye-hemi, and then shows how you can replicate the results by simply warping the corners of an image to correct horizontal or vertical fisheye distortion, allowing you to correct them individually. Here's a link to an image from that article that shows what I mean nicely: https://www.lonelyspeck.com/wp-content/uploads/2014/06/Screen-Shot-2014-06-16-at-8.19.32-PM-1024x640.jpg The benefit of correcting horizontal and vertical distortion separately is that you can get much more normal looking people in your photos without overly correcting other aspects of your photo. Also, if you correct both, you can get a wider field of view from your fisheye lens than the rectilinear correction gives you. I've replicated these results in gimp and the approach works well, but it's a bit time consuming, and I think this would be a relatively simple module to add to darktable. I suggest having a module with the following options: * stretch the corners horizontally or vertically * choose by how much * choose what part of the image you want to be considered center, ie, the horizon These three options should make it easy to correct the distortion for most types of fisheye lenses, whether or not they're in the lensfun db, and especially when the rectilinear correction doesn't give you great results. What do you all think? ___________________________________________________________________________ darktable developer mailing list to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org
