|Which lenses work with this method?
All lenses will work with this method. You'll just need a lot more images
to complete the sphere with longer focal lengths. The first part of the
method is also useful for stitching cylindrical panoramas together, but then
it's also pretty much the same as other tutorials on PT Tools for this.
For 'complete' panoramas though you can still use a wide range of lenses.
It can (and has) been done with 'ordinary' lenses. The fewer the images you
have, the fewer the control points you need, the fewer the stitches you have
to prepare and, obviously, the quicker it takes. My personal preference
would be at least a lens that enables you to shoot one horizontal strip of
images and one vertical image to patch in the remaining gap. For that you're
looking at a full frame fisheye. Circular image fisheyes can in theory
create complete panoramas with just two images however I have found it
easier to get very high quality images using a horizontal row and vertical
patches as well.
Full Frame Fisheyes: Rectilinear of Plain Jane
One of the greatest features of Panorama Tools is that it is capable of
correcting virtually all lens distortion. This makes the question of
distortion irrelevant then, which brings to the other requirements of a
lens. The other two things you need to look for are light fall off
toward the edges and edge to edge sharpness. While Panorama Tools will
compensate for light fall off from the centre of the image this will not
necessarily correct all colour/contrast variation that can occur.
Practically all lenses will have light fall off towards the edges because
they are stretching the image more at the edges than at the centre of the
image however this can be more pronounced in poorer quality lenses. Image
sharpness is perhaps the most critical quality of a lens for panoramas
though. Try before you buy and check the sharpness at the edge of the
Circular fisheye images are, well, circular and represent a view of
around 180°. Unlike all other lenses though there is no attempt to stretch
the image to reduce distortion. This means that there is (practically) no
light fall off towards the edges of the image. This makes stitching SO much
easier. With only 3 horizontal images required for a panorama it is also
much easier/faster to shoot a panorama and with 180° filed of view it is
also easier to deal with lens flare from the sun and other bright lights
Autofocus or Manual Focus
If you believe the sales pitch they will tell you that there is
practically no difference in image quality between manual and autofocus
lenses. And yet when I look at the specs for my manual focus lens it has a
much different configuration of elements from its autofocus counter part.
And autofocus on an 8mm lens?? You could make a fixed focus 8mm lens
with a rotating focus collar that did nothing and most people wouldn't
notice. The focusing mechanisms of autofocus lenses are of necessity very
sloppy. I don't like that, and after a lot of persistence I finally managed
to get the importer to a) recognise the existence of a manual focus version
of my lens (you know, the one in the brochure and on their website?) and b)
actually order it.