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