"Mark Thomas" wrote in message
...
Troy Piggins wrote:
* Mark Thomas wrote :
More work in progress..

http://www.marktphoto.com/examples/pano_night1_test.jpg

Fuji S9000, fl~35mm, 3s f5.6, 5 images, PTGUI, adjusted levels/sat,
lightly denoised, reduced to about 1/3 size and USM.
(Need any of this explained or elaborated? just ask..)
snip /

G'day Mark.

Cheers, mate - nice to see you still pop by occasionally!

I've been thinking about panos lately.
Try to resist, even though the Force is strong!! I think they are
starting to take over my hobby completely... aaargh..

I don't have
a pano head, so trying them handheld. Having trouble I think
because the lens I'm using is too wide and getting like a fisheye
effect in each frame which is not condusive to the stitching.

A lot depends on the software you are using.. ? I don't *normally*
hesitate to use mine right down to 28mm with PTGUI, but.. read on..

What lens/focal length should you use?
It depends.. If most/all of the subject matter is a reasonable
distance away from you, then you will probably find you are ok down to
28mm, and handheld will suffice in most cases as long as you watch
what you are doing. But if there is stuff up close to you, it will
all get very tricky without that pano head - and longer f-l's will
help.

The image above is a case in point - I didn't shoot it very carefully,
and it was at about 35mm f-l. The handrails and foliage were all
quite close to my location.. When I gave the images to PTGUI, it did
a fine job with the background stuff, but obviously had a problem with
the handrail area. What you see is exactly what PTGUI gave me with no
intervention on my part.

I *did* briefly try adding a few control points to bring the handrail
into line, but PTGUI basically told me I was asking the impossible. I
told it to go ahead and try anyway - but when it tried to reconcile my
inputs it had to change focal length assumptions and re-align (and
misalign) stuff. In other words, it all went badly wrong because the
parallax issues were too great for *automatic* stitching.

It's a bit like the linear/stepped out issues that were beaten to
death some time back. Too much parallax = no panorama!

However... In this rather mild case, what I would do is simply go
back to PTGUI's original default effort and ask for a PSD file - which
has all the source images (deformed and aligned appropriately) as
layers. Then I can use Photoshop to fiddle with it - a bit of erasing
and stretching will have those rails sorted in a reasonably short
time. I've done that sort of thing before, notably on this one:
http://www.marktphoto.com/examples/brisbane_pano_bw.jpg
which had some similar problems.

So it's horses for courses.. it really depends on the original scene
and the software you are using.

In summary, yes a pano head will help a lot if your pano's have a lot
of deopth or close up stuff. So will using longer focal lengths, but
of course the penalty is the extra time and effort.

And to minimise the effects of that, should you shoot with
horizon dead centre, as opposed to rule of thirds?

Again, it depends somewhat on the capabilities of the program you
stitch with. The less the program has to stretch/distort images the
better, so I guess yes is the answer.
Plus panoramas by their nature tend to be
'what-you-would-see-if-you-turn-your-head-around', so a level-ish and
centred horizon seems to work better, for me anyways..

And you can always crop high or low - increasingly I am shooting the
source images portrait-ways, so I have a fair bit of head- and
foot-room ..

Hope that helps, sorry I waffled on..

mt
Hey neat pic..
Maybe your onto something in your stitching..
Escher's illusions and your handrails are on the right track for an
Escher..
http://www.techeblog.com/index.php/t...hers-waterfall

--

73
Hank WD5JFR