wwp@yahoogroups.com:
Re: Help PTgui Nikkor 10.5 lens setting
Erik Krause 2005-Oct-10 20:08:00
Am Sunday, October 09, 2005 um 6:48 schrieb thinnairstudios:
> I keep getting "about" answers. Can't we find the"EXACT" field of
> view for this lens.
The optimizer optimized the value to 87.4449 portrait or 131.524?
landscape orientaion in some recent panos I've stitched. However,
these exact values are only valid in conjunction with the a, b, and c
lens correction parameters, since those can slightly compensate for
wrong FoV.
> I forgot to tell you I am using the Nikon D70s
> The manual sais the sensor is: 23.7mm x 15.6mm
> The focal length is 10.5mm
>
> Using this formula: found here http://epaperpress.com/pano/
> g = sensor width
> f = focal length
> h = horizontal FOV
>
> h = 2?atan((g/2)/f)
This is the formula for rectilinear mapping. The formula for fisheye
mapping won't have a tangens otherwise it wouldn't be able to cover
180? or more. Use R = 2 * f * sin( FoV/4 ) instead, or resolved:
FoV = 4 * asin( R / (2*f))
To solve your problems: in PTGui choose Fullframe as lens type, make
sure there are control points in all overlapping images. Optimize for
FoV and b, later may be for a nd c, too. However, this will fail if
you have large parallax errors in your images. To verify this, delete
all control points that are on nearby objects and eventually set
additional on far objects.
> I have applied for membership at the panotools group but have not
> received an email from them yet.
Sure you tried <http://groups.yahoo.com/group/PanoTools/>?
Please try again to join (check your spam filter and your settings,
perhaps you choose "No Email") You'll (and Dave and the other
interested fellows) find any help you need there...
best regards
--
Erik Krause
Offenburger Str. 33
79108 Freiburg