Hi Peter!
You are talking two entirely different things here. 1) is tilt correction. 2)
is Fisheye distortion.
Allow me to try to explain things a wee bit... as an owner and happy user of
the Olympus 9mm Fisheye and a regular tilter of horizons.
1) In my preferred RAW developer, RawTherapee, there is no limit to tilt
correction. If you are 46 degrees off the horizontal, it will snap the line
you select to vertical. If you are only 44 degrees off the horizontal, it will
snap the line you select to perfectly horizontal. Other features allow you to
rotate the image as much or little as you wish. I don't know what Lightroom
will do, but I'm willing to bet its similar. And these two programs are not
alone.
2) Fisheye distortion is a bit more of a puzzle. While many programs can cure
barrel and pincushion distortion, automatically .. fisheye distortion is
another matter. To cure the fisheye distortion, I use PT Lens. It's an
excellent lens distortion correction tool and while not free, is certainly
inexpensive. Just $25 for a lifetime, with all updates and on as many
computers as you wish. I'm sure there are other alternatives.
PTlens has hundreds of lens distortion profiles (he claims more than any other
similar program) and will correct pushcushion & barrel distortion for nearly
any lens automagically. But, for fisheye lenses, the cure is a manual slider.
Because of the nature of fisheyes, the slider does no always work, at least not
totally. But it does a good job most of the time, in my humble experience.
A couple of years back, Rose and I were at a conference at the Banff Springs
Hotel and Rose wanted a shot of the bed. The BSH is an older hotel (1911 to
1928) and the rooms are elegant, but small. So, the fisheye was the only
solution.
Here is the shot, as taken....
http://www.furnfeather.ca/temps/Banff_1.html
And here it is, after using the slider....
http://www.furnfeather.ca/temps/Banff_2.html
I also downloaded the sample you mentioned, but (I think) because the lens was
angled upwards, the slider in PT lens was not able to correct that photo.
I hope this helps you.
David.
Hiya folks. I'm still working through my head the tilt-corrective------
capacity of software. For those of you who use software to correct tilt
in images, are there limits to how much tilt in an image can be
reasonably corrected? The question comes from my seeing an image within
the B & H Photo website on the image sample page for folks who had
purchased the Olympus Fisheye Body Cap 9MM f/8. The image is linked
below, and specifically, could the bend in the buildings' walls be
reasonably straightened with no or very little evidence of the
correction if you were working with the original file? Thanks.
Best regards,
Peter Stevens
https://www.flickr.com/photos/159388964@N08/46606154101/in/dateposted-
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