Featureless zenith, how do you add CP

[digipano]

Featureless zenith, how do you add CP

by digipano » Sun Dec 28, 2008 7:03 pm

Due to my lens 10-20mm on canon 40D, I often get feature less zenith when shooting outdoors & its impossible to add CP on it in many cases since its plain sky.

Is there a way out?

[klausesser]

by klausesser » Sun Dec 28, 2008 7:18 pm

Is there a way out?

If is really without any feature: Photoshop --> clone-tool!

best, Klaus

[DrSlony]

by DrSlony » Sun Dec 28, 2008 9:46 pm

Even better to use APP to do this (smooths out better than cloning). If it really is featureless, just use the move tool to move the image to +90° in pitch and guess the yaw and pitch if you don't remember it.

I often shoot 4 images of the upper sky if there are no trees or buildings around to offer good CPs, each one just touches the zenith, and I almost always have to move them manually into place: yaw=0, 90, 180, 270; pitch=+90°; r=0°.

[digipano]

by digipano » Mon Dec 29, 2008 4:23 am

If is really without any feature: Photoshop --> clone-tool! cool

Sky is plain but it has gradient, not easy to photoshop when shot at noon with glaring sun looking at you.

If it really is featureless, just use the move tool to move the image to +90° in pitch and guess the yaw and pitch if you don't remember it.

I will try this suggestion, but there is a button "Guess unlinked image location" should that be used, I tried it but it doesn't do the job of guessing the location.

Last edited by digipano on Mon Dec 29, 2008 4:24 am, edited 1 time in total.

[mediavets]

by mediavets » Mon Dec 29, 2008 9:48 am

If it really is featureless, just use the move tool to move the image to +90° in pitch and guess the yaw and pitch if you don't remember it.

I will try this suggestion, but there is a button "Guess unlinked image location" should that be used, I tried it but it doesn't do the job of guessing the location.

It will work sometimes.

But if not you can edit the Y/P/R values directly in the Layers data table in Move Images Mode, as in screen shot.

If shooting with a click stop pano head in a regular sequence you will know both the pitch and yaw values for zenith shot eg. if zenith shot last then yaw value will be same as previous shot in the sequence and pitch will be +90 if taking a straight up zenith shot.

Last edited by mediavets on Mon Dec 29, 2008 9:51 am, edited 1 time in total.

[digipano]

by digipano » Mon Dec 29, 2008 1:22 pm

Manually adding +90 solves the problem but since its a 5 shot bracketed HDR I have to change that manually in all the images of the series.

Do I need to optimize after changing the value, if I do so then the value again changes on optimization.

Most of the time I shoot hand held nadir so the height changes & there is a shift in YPR values, cant APG cope up with such nadir?

Finally I go this as per the suggestions.

Last edited by digipano on Mon Dec 29, 2008 1:38 pm, edited 1 time in total.

[mediavets]

by mediavets » Mon Dec 29, 2008 1:59 pm

Manually adding +90 solves the problem but since its a 5 shot bracketed HDR I have to change that manually in all the images of the series.

Do I need to optimize after changing the value, if I do so then the value again changes on optimization.

.

Many recommend/prefer to pre-process bracketed shots with HDR/exposure fusion program BEFORE stitching.

There is no need to optimise again - if you do then you'll again lose the position of the orphaned unless you hard link the manually positioned orphaned image to a neighbouring image(s).

[mediavets]

by mediavets » Mon Dec 29, 2008 2:09 pm

Finally I go this as per the suggestions.

In this situation - for this kind of scene - you might consider shooting another row of say 3 or 4 shots at less than +90 rather than a single +90 that way you would be more likley to get a good link between the 'zenith' shots and the next row down, and would still have good zenith coverage.

Or get a fullframe FE lens and not have the problem?

[digipano]

by digipano » Mon Dec 29, 2008 2:13 pm

Many recommend/prefer to pre-process bracketed shots with HDR/exposure fusion program BEFORE stitching.

that's true but that is too many shots to fuse, I prefer to process as layers in APP &then fuse them in external program. Its much faster & I get 3 layers to play with various HDR programs.

There is no need to optimize again - if you do then you'll again lose the position of the orphaned unless you hard link the manually positioned orphaned image to a neighbouring image(s).

There is so much in APP to discover, I didn't even know that hard links existed till this post. Thanks for telling me that. I will use the hard links.

APP documentation needs weekly revision by the users else you soon find yourself lost.

Or get a fullframe FE lens and not have the problem? wink

I have ordered sigma 8mm but its not available to me in the local market, my issue with FE would be the CA correction of all the shots & the flare when shooting against light & some times I need more resolution than the FE 6 shots around.

Last edited by digipano on Mon Dec 29, 2008 2:19 pm, edited 1 time in total.

[mediavets]

by mediavets » Mon Dec 29, 2008 3:00 pm

Hi,

I'm not sure that the hard link feature is documented.

I think I learned about from a post on the forum too.

The Sigma 8mm f3.5 is not a fullframe FE - it will instead produce a cropped circular image on your 40D. But the Tokina 10-17mm zoom FE can act as a fullframe FE on the 40D - by which I mean you would get an image that completely covers the sensor and which would be close to 180 degree FOV on the diagonal - it would be 180 FOV on a 1.5x crop Nikon body, I think it may be nearer 170 FOV on the 1.6x crop Canon body? - and which would give you a considerably higher resolution stitched pano for the 'penalty' of just a few more shots for 360x180 coverage.

Last edited by mediavets on Mon Dec 29, 2008 3:03 pm, edited 1 time in total.

[klausesser]

by klausesser » Mon Dec 29, 2008 3:02 pm

Manually adding +90 solves the problem but since its a 5 shot bracketed HDR I have to change that manually in all the images of the series.

Do I need to optimize after changing the value, if I do so then the value again changes on optimization.

Most of the time I shoot hand held nadir so the height changes & there is a shift in YPR values, cant APG cope up with such nadir?

Finally I go this as per the suggestions.

Render a pano. Put it in CubicConverter (or a relating tool) and generate cube-faces. Take the top-face into Photoshop and use the clone-stamp to close the hole - and after that the "Patch"-tool to equalize perfectly a cloned part from nearby the hole to cover the hole.

I often use it with Zenith issues - and other sky-problems. Works great when you correctly choose "source" or "destination".
It´s a very fast way.

best, Klaus

[DrSlony]

by DrSlony » Mon Dec 29, 2008 5:34 pm

digipano: you optimise only if you change control points. Since you are moving an image manually into place and not touching any control points, optimising is useless, you will just end up having to level it again.

"Guess unlinked image location" works great when you position an image at the start and end of a row, hard link them to the ones with the row below, and the images in between are garbled up. Then APP usually spaces the garbled up images evenly between the two hard linked ones.

Code: Select all

10                              19
01  02  03  04  05  06  07  08  09
11,12,13,14,15,16,17,18

These are unlinked and garbled up: 11,12,13,14,15,16,17,18
10 is hard linked with 01, 19 is hard linked with 09.

If you use smartblend for rendering, you will notice that some panos have a pinched zenith, a very visible cone. You will have to render those panos twice: once using smartblend for the whole pano, and another time using multiband for just the sky, so it doesn't pinch the zenith. I used to fix pinched zeniths using clone/heal, but the end result was never satisfying, there are just too many gradients coming in from different directions sometimes, especially if you use a polariser (sometimes a bad idea for a pano, sometimes great), so I recently started to always just re-render using multiband to get the best quality zenith. I hope smartblend2 wont pinch the zenith.

klausesser: if you shot the zenith, letting APP blend it in will give you a better, smoother result than cloning/healing it, and faster.

Has anyone figured out when APP pinches the zenith when using smartblend? It doesn't always happen to me, just sometimes.

Last edited by DrSlony on Mon Dec 29, 2008 5:35 pm, edited 1 time in total.

[klausesser]

by klausesser » Mon Dec 29, 2008 7:22 pm

klausesser: if you shot the zenith, letting APP blend it in will give you a better, smoother result than cloning/healing it, and faster.

depends . . i wouldn´t globalize . . . - as i told: i use it often. It´s fast and you wouldn´t realize it.

best, Klaus

[GURL]

by GURL » Mon Dec 29, 2008 7:25 pm

In this situation - for this kind of scene - you might consider shooting another row of say 3 or 4 shots at less than +90 rather than a single +90 that way you would be more likley to get a good link between the 'zenith' shots and the next row down, and would still have good zenith coverage.

Because source images are not square but rectangular there is not any reason to place the center of the zenith shot at the exact zenith location.

In most cases a pitch value like 70 degrees (rather than 90) is enough to cover the zenith hole. As a result the top part of a building, a tree or some mounts can often be used to link this shot to the other ones (but, yes, this is not very helpful in a flat sand desert... )

For a 10 mm rectilinear lens I would try: 5 shots along the horizon spaced by 72° + a single shots for zenith using a pitch value of 72 degrees (as ilustrated in my next post.)

[GURL]

by GURL » Mon Dec 29, 2008 7:38 pm

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