Stiching panorama - horizon curved

[deutronium]

I've just created a panorama using Hugin, but I can't figure out why the horizon is curved:


pan.jpg by strangedoodle, on Flickr

[tived]

Hi,

I haven't used hugin for some years now, so please forgive. But you should be able to straighten out the pano within the program. At least you can with PTGui Pro

Otherwise just tell people its the earth curvature ;-)

Henrik

[Bart_van_der_Wolf]

I've just created a panorama using Hugin, but I can't figure out why the horizon is curved:

Hi,

It's because the value of your overall 'pitch' parameter is not correct. You must lower the horizon in the image.

Cheers,
Bart

[Peter McLennan]

In Photoshop: Select All | Edit | Transform | Warp

[deutronium]

Really appreciate your help guys!

I'm now wondering did I do something wrong when I took the photos?

I tried to make sure the tripod was level, and then just rotated the head.

[Slobodan Blagojevic]

Tripod does not have to be leveled, but both the head and the camera should be. It is very useful to have a tripod-head leveling device between the head and the tripod.

[Ellis Vener]

Tripod does not have to be leveled, but both the head and the camera should be. It is very useful to have a tripod-head leveling device between the head and the tripod.

In essence putting a tripod head leveling device underneath a tripod head is essentially stacking to tripod heads on top of each other, although the lower one generally will have limited movements and no panning function  It works for some set ups but not for others. I prefer to use something like the Really Right Stuff PG-02VA on top of a tripod head that has a panning mechanism ( similar to the RRS PCL-1) on top of the head  - but you'll need either a short bar or small plate to mount it to the horizontal  rotation device . This arrangement lets me use the tripod head to level the rotation base and tilt the camera. Of course if you are shooting fro ma high enough perspective and your angle is wide enough you may see the natural curvature of the horizon.

I like Really Right Stuff gear for it's quality and versatile modular design but recognize that there are alternatives, some less and some more expensive than RRS's products.

[fike]

In Photoshop: Select All | Edit | Transform | Warp

It will be difficult to make this straight with photoshop warp.  You are better off fixing the pitch as others have suggested. I also think you need to fix the center point (left to right, also sometimes called yaw).  I think the yaw is off because the bowing effect doesn't start from the middle of the image. The apex of the horizon's bow is somewhere off to the left side of the image center.  

I haven't used Hugin, so I can't comment specifically about its strengths and weaknesses, but these problems are extremely easy to fix in PTGUI by simply dragging the preview image up and down and left and right until it looks straight.  

As someone else mentioned, problems with the horizon (particularly the yaw) are often caused by the panning base not being level.  As Ellis said, RRS gear mounted on top of a leveling base or ballhead are very good for avoiding these types of problems.  With that said, your problem here is probably fixable in software, but using the RRS head on a level platform would make this stitch very easy to execute without much hassle.