Originally posted by heliphoto
It seems that the most recommended program would be PTLens, and other programs which use the PTLens database, and it seems to me that the PTLens database doesn't include the Pentax DA 10-17 FE, which is the lens in question for me.
So if you've succeeded in de-fishing your shots from this lens, would you mind sharing your secrets with me? (or at least pointing me toward a tutorial out there somewhere.)
Thanks.
Well, I don't have the 10-17FE, and I don't use PTLens, but since the package I do use
(
hugin - Panorama photo stitcher )
uses the same lens distortion model, this might be applicable to your problem (or you could just use hugin
)
Here's a de-fished image (the source image is at the head of the fisheye fever thread)
(
click here for larger versions of this image)
Four parameters are most important:
The
lens type (fisheye)
The
horizontal field of view of the input image; For a sigma 8mm this is 185 degrees; for a pentax 10-17 I'd expect this to be about 140 degrees at 10mm and about 82 degrees at 17mm
The
projection type of the output image (rectilinear)
The
horizontal and field of view of the output image (choose anything less than the HFOV of the input; in the image above it's about 120 degrees)
Hugin (I'm not sure about PTLens) also allows you to specify the
pitch (up or down) of the input image; this is lets you do de-fishing and perspective correction in a single pass.
Using the hugin GUI:
load a single image
specify the HFOV and lens type (fisheye) of the lens,
go to the sticher tab
set projection to rectilinear
set desired horizontal and vertical FOV
click on "calculate optimal image size"; you might want to reduce this
for output:
uncheck "blended panorama"
check "remapped images"
Click "stitch now"
The easy way once you set it up:
I found it more useful to use a batch file that calls dcraw to do the RAW->TIFF conversion, and then calls nona (the hugin remapper) directly to generate a de-fished TIFF image. Then I go into photoshop or GIMP to tweak the levels and make the JPEG.
I've attached an example; a bunch of stuff (-C parameters to dcraw, parameters described above, paths to dcraw.exe and nona.exe) would have to be changed for your situation
Last edited by troyz; 08-02-2008 at 08:05 AM.