Large Pano File & Wandering Seams

[Cantab]

After doing a successful 3 photo panoramic merge in Photoshop, I've now done a pano merge of 26 photos. The images were taken with a 200mm lens, handheld and covering a horizontal sweep of probably 90 degrees. Despite not using a tripod, the images line up horizontally reasonably well. The photos were of Mt. Baker and a long sweep of mountains north and south. The mountains are perhaps 100 kilometres (or miles) away from where I took the photos.

The resulting merged file is 4.2 gigabytes! The image has a number of what look like wandering (not straight) stitch lines. I'm going to retry the pano merge perhaps with Photoshop or one of the dedicated software programs. I've read the three CiC tutorials on panoramic stitching but didn't see anything about wandering stitch marks.

Any thoughts, comments or suggestions would be much appreciated.

[Shadowman]

Can you post an example? Did you slightly overlap between each successive image?

[Polar01]

Bruce: just flatten the image and go one about processing it. You will never get straight edges as it looks and compares the images and looks for the best fit and that will not be a straight line. Every time you put together a panorama using the same shots the computer will put it together differently.

Cheers:

Allan

[dubaiphil]

I used to get that in Photoshop too. Like marching ants?

Have you flattened the layers? That may fix things. Otherwise you'll have to use the clone tool, which kind of goes against all that 4.2Gb loveliness. Which is why I moved onto PTGui

[Cantab]

John and Allan, thank you for your comments.

I should have added that some of the wandering "seams" sometimes turn and run horizontally. These wandering seams typically run through forest land on islands in the foreground (a few kilometres from the camera, not the much more distant mountains). I'll see if I can post a small sample when back at my computer in a couple of hours.

[Cantab]

I used to get that in Photoshop too. Like marching ants?

Have you flattened the layers? That may fix things. Otherwise you'll have to use the clone tool, which kind of goes against all that 4.2Gb loveliness. Which is why I moved onto PTGui

Phil, yes: like marching ants. I'll try flattening the image and see if the ants disappear. Have you tried Ptassembler? I believe it's shareware and therefore less expensive than PTgui. I don't anticipate doing large panos on a regular basis but having taken these 26 photos on an unusually haze free day I want to get a good final result.

[dje]

Bruce I've also had visible "wandering" seams in an image stitched in CS6 but they have disappeared when the layers were flattened. Not sure whether this is what you are getting or not.

Dave

[dje]

Here's an example

Before Flattening Layers



After Flattening Layers

[Cantab]

Bruce I've also had visible "wandering" seams in an image stitched in CS6 but they have disappeared when the layers were flattened. Not sure whether this is what you are getting or not.

Dave

Dave, yes, your screenshot shows exactly what I got. I took your and others' advice to flatten the image and presto, the wandering seams/marching ants disappeared before my eyes.

The next issue is vignetting at various points in the panorama. I'm hoping that will be easily dealt with by redoing the merge but this time ticking the vignetting removal box.

And then there will be trying to minimize the haze. The scene was clearer than I'd seen it for a few years but I'll still try to see if I can improve on nature. Dave, I have a recollection that you posted a picture of Mt Baker last year, taken from the top of the Malahat?

Thanks to everyone for your comments.

[dje]

Bruce this may be the thread you are referring to. I think it's Mt Baker, taken from a BC Ferry. The posts touched on using LCE (US mask with small amount of large pixel radius) to reduce haze. The Levels adjustment was also used aggressively.

Dave

[loosecanon]

!) I would always go for a manual exposure so exposure is constant across the set of images for a panorama.
2) Tripod does make a difference inlining up and exposure across frame.
3) Correct for vignetting should be corrected before stitching, or if bad overlap images to avoid using corners.
4) Photoshop is not the best at merging for correctness. Remember before you flatten you can change the boundary point by painting on the mask
5) Small corrections best done by using spot healing brush set to content aware, great for getting rid of narrow lines.

However I suspect you might get a better image by using less images

[Cantab]

Bruce this may be the thread you are referring to. I think it's Mt Baker, taken from a BC Ferry. The posts touched on using LCE (US mask with small amount of large pixel radius) to reduce haze. The Levels adjustment was also used aggressively.

Dave

Dave, yes, that's definitely Mt. Baker that you photographed. Thanks for providing the link to your thread. I'll reread it carefully.

[Cantab]

Yes, aka Loosecanon, thank you for your comments.

Although I'd not thought about it, your first point makes a lot of sense. Thankfully I photograph most things with manual exposure -- I did everything manually for many years and I suppose do not entirely trust the automated exposure programs. I've redone the merge with the vignetting option turned on and things turned out well -- once I'd flattened the layers.

Once I've done the usual pp, I'll post the final image although it's very wide width may pose a challenge.

[Cantab]

I've just posted the final product here: Mt. Baker and Coast Range Panorama.

Thanks again for the assistance in working on this pano.

[Manfred M]

While I agree with a lot of the comments; I find that Photoshop actually does a reasonably good job on stitching panos; I uses CS6 on this.

I shot this one using a tripod (on manual; I shot RAW and picked a mid-point as my exposure); the shot was around 230 degrees and made up of 29 images. I shot this with my f/2.8 24-70 at 36mm and cleaned up vignetting, CA and distortion in ACR.

The imported and stitched file did have a bit of curvature at both ends of the pano.




And the final crop with PP work:





When I pixel peep, the only misalignment I can make out is with the power lines and they can be shifted up by a few pixels or so (I suspect this was due real movement). When I looked at the selection PS made it really looked like a bit of a jig-saw puzzle when the pieces were pulled together. A bit of each image made it to the final pano, but the way the software selected them is really a mystery to me.

The final image is a bit of a monster 21840 x 6383. It does take a while to load, but when you get a closeup view of the power lines, you can see the small alignment misses.

[Colin Southern]

While I agree with a lot of the comments; I find that Photoshop actually does a reasonably good job on stitching panos

Same - this is a 13 shot composition - hand held - with a 70-200mm lens. I think a generous overlap is key (I use around 20%)

[inkista]

... Have you tried Ptassembler? I believe it's shareware and therefore less expensive than PTgui. ...

I should perhaps point out that there is a (free) open source alternative to PTGui, Hugin.

[John 2]

I understand that in order to totally eliminate mismatch between images taken for a panorama, you should rotate the camera around the plane of the front lens element and not the film (sensor) plane. There are mounts that allow you to do this. Like everyone else however, I settle for less than perfect and hand hold or rotate the tripod head.

[Colin Southern]

I understand that in order to totally eliminate mismatch between images taken for a panorama, you should rotate the camera around the plane of the front lens element and not the film (sensor) plane. There are mounts that allow you to do this. Like everyone else however, I settle for less than perfect and hand hold or rotate the tripod head.

Around the entrance pupil / nodal point. In reality - for distance shots, it doesn't make any difference, but if there's something in the foreground then yes - it won't align correctly if rotated around the sensor axis.

Really Right Stuff make nodal bars that make it pretty easy -- in reality it's just a bar that connects to the tripod head and then the camera connects to the bar so it offsets it by roughly however long the lens is.

[chauncey]

Photoshop has numerous merging techniques and they will all cough out different results, additionally...
using the same technique over and over may turn out different results, Don't quit after the first try.