On 2/3/25 20:24, Greg 'groggy' Lehey wrote:
On Monday, 3 February 2025 at 20:08:38 -1000, David W. Jones wrote:
On 2/3/25 16:16, Greg 'groggy' Lehey wrote:
I have recently got a 7Artisans 4 mm f/2.8 circular fisheye lens with
an angle of view of claimed 225°. I'm using it on an Olympus E-PM2,
and I'm having no luck at all stitching panoramas. I suspect that
there is some issue with Hugin misinterpreting the Exif data, but
before I go to even more work, a question: is anybody using a lens of
this nature? Are there any tricks?
One thing that is interesting: the "focal length" popup sometimes
reports a horizontal angle of view of 248° (close enough, since it's
way off the end of the image), but at other times 186°, which is
clearly wrong. Is there any way to tell the GUI or the underlying
scripts what the real angle of view is?
I tried several different ways of generating control points with
your JPEGs, and was unable to generate any control points connecting
any images.
I think that's actually less success than I had. I did get some
control points, but there were other issues before that. In
particular, the second image was always masked in a "fleur-de-lis"
pattern (see first attachment). It didn't make any difference which
image I loaded second, and if I loaded the same image again it was
correct. See the first attached image.
I manually added some, but alignment didn't give me anything except
a jumble of spikes.
Did you set the lens type to circular fisheye? What angle of view did
the GUI claim? I did get something like a panorama, but it was
useless (second image).
I didn't change the lens type, I just left it to whatever it
automatically selected. I've never used a fisheye lens at all, so I have
no idea what settings or such might be needed.
I don't remember the angle of view it claimed. It reported the 4mm focal
length and about a 21x crop factor.
Sorry, I have no other ideas. I don't know if everything's being
affected by the pronounced chromatic distortion around the edges of
each image, but I know nothing about using fisheye lenses like
yours!
Thanks for the try. I was really hoping to find somebody who had been
there before, and maybe somebody will pop up. FWIW I regularly make
panos with an 8 mm full frame fisheye, and I don't have any issues
there. I'm beginning to think that this might be a bug.
Only thing that occurred to me that might be a bug is that I was
expecting a lot of barrel distortion correction, just based on how the
images looked and the wide field of view. I don't remember seeing much
correction for that from Hugin.
Hopefully, someone that uses these kinds of lenses and knows what
they're doing will chime in. I'd think that a 235deg field of view would
mean you don't need three images, just two, to cover 360deg, but what do
I know?
--
David W. Jones
[email protected]
wandering the landscape of god
http://dancingtreefrog.com
My password is the last 8 digits of π.
--
A list of frequently asked questions is available at:
http://wiki.panotools.org/Hugin_FAQ
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