hi everybody,

Now that the thoby Projection is available in Hugin/panotools I was able
to run some tests using my 10.5 on a Full frame camera (5dII)

I can say that the thoby is a better match than what we call "circular
fisheye". How much better? It is hard to tell, as we don't have a good
that measures the goodness of registration between 2 photos (I guess we
could use Imagemagick's 'compare', but we need to indicate it to use
only the intersection of the mask between the two images). In reality,
when one uses a "b" parameter, the differences are small.

One thing I am surprised is that I am getting an effective field of view
of 141.8 degrees, which translates to a lens of 9.69 focal length, which
sounds wider than it should be. But it is consistent with Pierre
Toscani's findings (In his excellent document describing the 10.5 at
http://www.pierretoscani.com/echo_fisheyes_english.html#fisheye2) who
gives it a horizontal field of view of 142 degrees (in vertical mode).

But I still need a b correction parameter of 0.04411 (which is not too
bad).

I would say that proper rotation around the nodal point is
far more important than using one projection over the other. The thoby
improves slightly the match of photos towards the periphery of the lens,
which means more of the original photo can be used. 

I suspect that most users will not see a major improvement of one over
the other.

Pierre Toscani mentions that this lens has a slight curve beyond 180
degrees, and I can observe that in my tests. So I recommend to crop the
far outside of the image.

It might be possible to create a 360x140 pano with 2 photos, thought,
but there might be deformations in the area where they meet.

Speaking of cropping. Hugin should be programmed to crop images for
Thobys in the same way it does it for Circular Fisheye.



--
Daniel M. German                  
http://turingmachine.org/
http://silvernegative.com/
dmg (at) uvic (dot) ca
replace (at) with @ and (dot) with .

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