Help (learning) with Panorama

[JDługosz]

I've merged the original exposures into a panorama using PS's photo merge tool, and then used the Adaptive Lens filter to straighten it out. The merge gave a cup shape to the horizon. The Adaptive Lens filter wasn't as easy as expected, as just marking the horizon was not working and I could find no way to tell it that the projected line it drew was not following the right curve! But I found that making a bunch of overlapping small lines did the trick.

So here's what I have now:

Before I work on color, I need to get the composition right. The distant horizon is straight, and the change in features on the left is a natural place to have a bend, but maybe the distant horizon ought to be a bit curved after all? I'm open to suggestions.
The near space is too distorted and doesn't match, but having the feature provides for the opening up of the distance beyond it. But maybe it can be shaped or modified somehow?

Any suggestions or discussion on what I should do next?

Also, I've found that PS will not save a file if it runs larger than 2GB. A more enormous merge could not be saved with layers intact. This thing is already pushing 2GB, with one "smart" layer + the lens filter and a vibrancy adjustment layer.

 

[Tom Mann]

#1 - Instead of using the Adaptive Lens filter to merge the component images, use either PS's photomerge tool, or any of the 3rd party panorama tools. In my experience, it's best to use the Adaptive Lens filter only to make relatively small touch up level corrections to either single images, or merged panoramas.

#2 - Keep the camera absolutely level (ie, to within, say, 1/2 degree) as you rotate, ie, put the camera on a tripod, and level it up precisely before taking the component shots. You might occasionally be able to do it by hand, or with the tripod not level, but it will be a hit or miss proposition, and if you miss, the result will look like your example image.

Tom M

 

[JDługosz]

Tom, I did use PS's photomerge tool. That gave a bent picture, the horizon looking like a big smile. Then I used the Lens filter to un-bend it.

What's wrong with the alignment of hand-held images that show up in this example image?

(I shot two rows: left to right pan with the horizon in the frame, and another row left-to-right "below" that)

 

[Tom Mann]

Thanks for clarifying the steps that you used.

The problem of curved, or even undulating horizons, as well as distortion of areas near the camera is very well-known to people doing panoramas. As I suggested in my previous post, it's almost always caused by a camera that is not level and/or not rotated (between exposures) around a perfectly vertical axis. In fact, people serious about panoramas actually use spirit-level type devices to level the vertical axis of their tripod together with artificial horizon tools on their cameras to level the mounting of the camera to the tripod.

Probably the best way for you to become acquainted with this aspect of making panoramas is to read some of the excellent articles on the subject. These are much more comprehensive than I could do in this thread, e.g.:

http://www.theperfectpanorama.com/articles/problem-6-horizons.html
or just Google {panorama stitching curved horizon}

At the next level of care in generating panoramas, if you don't rotate the camera around a very specific point in the middle of your lens, then serious problems in the foreground develop. Of course, entrepreneurs have come up with specialized equipment to attach a camera to a tripod to allow rotation around the nodal point. For example, look at these devices (in order of increasing price, the last one being automated):

http://www.bhphotovideo.com/c/product/838676-REG/Nodal_Ninja_N4_PKG_NN3_MKII_Starter_Package.html
http://www.bhphotovideo.com/c/produ...h057a4_long_Deluxe_Panoramic_Head_Geared.html
http://www.bhphotovideo.com/bnh/controller/home?O=&sku=689697&Q=&is=REG&A=details

Of course, many people want to take panos without going through the preparation steps described above, so better panorama stitching software includes tools to try to help them out. Of course, the results are never as good as if you "got it right" in the camera, but are a very useful adjunct if you got it close in the camera and just need the software to make some small tweaks. These tools are much easier to use than do-it-yourself approaches such as the one using the Adaptive Wide Angle filter that you tried. Here are some links to such software:

http://www.ptgui.com/man/straighten.html
http://www.johnhpanos.com/horizons.htm

HTH,

Tom M

PS - If I had to pick just a few hints to give w.r.t. making hand-held panos of landscapes with lots of interesting things above and below the horizon, it would be to:

(a) turn your camera to the portrait orientation (instead of landscape) so you can take just one row of shots, not two or three rows;
(b) allow plenty of overlap between the component images;
(c) do the absolute best you can to keep the horizon in the center of the viewfinder; and,
(d) don't just turn your body to take the component shots, but rather, shuffle in a tight circle around an imaginary point located in the middle of your lens.
(e) don't immediately crank your lens to it's widest angle position. Instead, use a normal or even a telephoto focal length, but take more component shots.
(f) try not to include too much foreground.

To prove that one can get reasonably good results with spur-of-the-moment hand-held shots, I made the attached image by following, as I recall, all of the hints given above.

 

[JDługosz]

I shot the photos on vacation, so I can't redo them now!

I thought the perfect level panning was needed to make merging easier, before nice software that stitches automatically. But... maybe I should do a lens correction to the image before merging? (Does Photoshop's feature do that? I would think so.)

The horizon was not undulating. It was a neat curve.
Here it is with the filters turned off:

if you don't rotate the camera around a very specific point in the middle of your lens, then serious problems in the foreground develop

that might be affecting me here. But I don't need a perfect reproduction, but something artistic, to show that you are standing on the edge of the precipice. I don't like the extended "apron".

These tools are much easier to use than do-it-yourself approaches such as the one using the Adaptive Wide Angle filter that you tried

Do you mean the tools are better at stitching together with the desired perspective to begin with, as opposed to having to clean up after Photoshop's Panorama Photomerge? When I read up on software, Photoshop built-in was one of the top choices! I guess it got points for "easy to use", and I want something with all the knobs and buttons to play with. [edit: maybe Cylindrical would do what I meant, instead of Auto.]

Hmmm. I tried using "Arrange" (only) on the same set, and it's not a nice two rows like I thought. PS did a great job of making sense of it, actually! Here is a better grouping, just one row (so no foreground or bottom of the middle distant part).


I think a piece of advice would be to know how the photos really fit together just plainly, rather than eyeballing separate images in a library view.

 

[Tom Mann]

OP: "...I thought the perfect level panning was needed to make merging easier,..."

Yes, it will make the merging easier, but, in addition, if you also have the horizon going through the middle of the frame, then after the default merging, the horizon will be very close to straight, not substantially curved as in your image. If the horizon is close to being centered, this means that the geometry corrections to straighten out any slight remaining curvature will be less and won't eat away at your resolution as much.
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OP: "...But... maybe I should do a lens correction to the image before merging?..."

Not doing a lens correction before merging didn't cause your curved horizon. However, it always helps to do it because the lens distortion correction and the lens vignetting correction (the two components of the lens correction), will take some of the work off the stitching algorithm, probably produce a higher resolution result (after the horizon is straightened), and reduce any brightness jumps at the seams in the composite between one component image and the next. So, yes, it's a good idea.
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OP: "...Does Photoshop's feature do that? I would think so. ..."

Sorry, but I am pretty sure that PS's stitching tool doesn't do that automatically. Run each component image through either ACR or LR before handing them over to Photomerge or a 3rd party stitching tool. However, if you apply any other efx (eg, color balance, brightness or contrast adjustments, sharpening, etc.) to the images in ACR or LR in this process, make sure that exactly the same settings for these effects is applied to all of the component images in the set.
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OP: "... The horizon was not undulating. It was a neat curve...."

I didn't say that it was. What I said was, "The problem of curved, or even undulating horizons, ... is very well-known to people doing panoramas."
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OP: "...Do you mean the tools are better at stitching together with the desired perspective to begin with, as opposed to having to clean up after Photoshop's Panorama Photomerge? When I read up on software, Photoshop built-in was one of the top choices! I guess it got points for "easy to use", and I want something with all the knobs and buttons to play with...."

Yes, although I haven't done a personal comparison of PTGUI in the last couple of years, if you will look at last link in my previous post, http://www.johnhpanos.com/horizons.htm , you will see that it has a "t2" control point tool (and many features to support it) explicitly for the purpose of ensuring straight horizons.
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OP: "...I tried using "Arrange" (only) on the same set, ..."

This was a useful exercise. In particular, notice that the horizon in each of the component images that can be seen in your "arrange (only)" view is about 2/3rd the way towards the top of each frame instead of half way up, where it should have been, and the result of this was that when they were assembled into a panoramic composite, this produced a curved horizon that bowed upwards at the center.

BTW, notice that the last link in my previous post (referred to above) intentionally did exactly the opposite of what you did. For demonstration purposes, he intentionally and incorrectly placed the horizon in each of his component images only about 1/3rd the way towards the top of the frame, not at the half-way point. This was (a) to show that the default composite would be curved upwards at the ends, not at the center, and (b) that it could be corrected using the tools provided in the software he was using, PTGUI.

HTH,

Tom M