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Any tips on how to stitch a combination of shifted and panned images?

PostPosted: Tue Mar 05, 2013 12:06 pm
by gddxb
Hi all -

I've got a set of 9 images, 3x3.

Within each column, the images are shifted, with the lens staying stationary, and the sensor shifted up and down the image circle.

Across the rows, the camera has been panned.

Makes sense?

I'm coming up against a load of problems trying to get this successfully stitched in APG.

Has anyone tried this before?

Kind regards,

Gerald.

PostPosted: Tue Mar 05, 2013 1:57 pm
by klausesser
gddxb wrote:Has anyone tried this before?

Yes - i used to use a P45 on a Linhof M679 for quite a time. No problems with stitching parallel shiftet shots in APG or PTGui.
Problems rise when you need XML due to featureless images - which can occur quickly with architecture-shootings due to
white walls, ceilings/floors and so on.

In my opinion there is no need for shifting parallel with backs when you use a good motorized head providing XMLs
and shooting a mosaic spherically.

I do it rather often - some time ago we compared the P45 on the Linhof again shooting a 3x3 mosaic by shifting the back around
to using a DSLR on a head.
There´s absolutely no difference compared to using a D800 or a 5D2 on my Panoneed-head - i could do all the
geometrical corrections in the editor which i can achieve using a Linhof or Sinar with sliding a digiback parallel.
Need to do more than 9 shots of course - but that´s a question of adding a minute or so.

A remarkable difference was in the dynamics of the P45 doing a single shot. I needed 2-3 step bracketing on the DSLRs to get
the same dynamics as from one shot of the P45.
Regarding you can´t use bracketing in all situations the high dynamic performance which some MF backs provide really is a big advantage.

But comes to a price . . :cool:

best, Klaus

P.S.: sorry, i overread that you also panned - that´s not making any sense in my opinion . . . ;):cool:
But i would say it all depends on the overlap you used.

PostPosted: Tue Mar 05, 2013 2:41 pm
by con
each row should stitch normally as far as i understand (just camera pan).

Stitch those 3 rows and then Photoshop them together. it may be asking a bit much to get APG to resolve the whole thing

*EDIT
or stitch the 3 rows and then import them into APG

PostPosted: Tue Mar 05, 2013 2:48 pm
by klausesser
con wrote:each row should stitch normally as far as i understand (just camera pan).

Stitch those 3 rows and then Photoshop them together. it may be asking a bit much to get APG to resolve the whole thing

*EDIT
or stitch the 3 rows and then import them into APG

The point is: shifting the lens or the sensor means shifting the optical axis.


best, Klaus

PostPosted: Tue Mar 05, 2013 7:12 pm
by gddxb
I went round and round on this until I got a workflow that, well, worked.

I ended up using Photoshop to merge the 3 sets of shifted images (creating 3 separate files, one for each column), and them brought those into APG to stitch.

The reason for the panning was that I couldn't get the horizontal field of view I was after by just shifting the lens. You're absolutely right about the dynamic range and malleability of the files though Klauss - it is very, very rare that I need to bracket shots with the IQ180.