Panorama Shot - distortion enquiry


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#1
Hi Guys,

I tried to do a Pano shot yesterday and after stitching up all the pictures, after all the vertical and distortion are corrected by the PTGUI software, i realise that all 4 corners, top and bottom of the picture are left with the "black" area (black canvas/backgroud) especially the bottom part and have to crop away. My question is, what technique to apply to prevent it so that I can have a larger foreground.




This is the shot, im referring to how do i take the picture properly so that when after stitch up, i do not have to crop so much of the sea away (the picture is left with so little "sea" now). Im fine with a little cropping, I understand that sometimes after some correction, you'll have to crop some part off but not like the picture above i got to crop so much "sea" away. Any advise please? thank you :)
 

#3
don't know whether you're talking about this... just trying to help... there's a very good pdf guide on the second link... hope this helps...

http://reallyrightstuff.com/pano/03.html

http://reallyrightstuff.com/pano/05.html
Hi thanks for helping, but its not what I'm looking for. you know when you correct distortions or straightening pics you will lose pixels and leave the blank areas. My question was more to, how to do I take Pano shots more properly so that when I stitch them up there wont be too much correction to do, as my photo posted above, you would have notice that I dont have much of "Sea" left as they were cropped away after correction.

thank you!
 

jaRv1s

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#4
shoot in portrait setting / getting a wider lens... ;p
 

KY1977

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#5
Shoot in portrait and use lens no wider than 35mm.
 

megaweb

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#6
You need to shoot
- portrait position to cover as much angle from top to bottom
- level your shots so as the pano coverage is the overlapped portion

More Pano tips, read this link
 

Dream Merchant

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#7
Don't use spherical rotational techniques, but linear pano motion instead. Shoot in portrait mode and avoid very wide lenses.
 

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#8
Easy. Take some more photos at the corner.

More precisely, take one photo in the middle. Take two photos (one higher, one lower) at left and right in the sense.
 

#10
You need to shoot
- portrait position to cover as much angle from top to bottom
- level your shots so as the pano coverage is the overlapped portion

More Pano tips, read this link
does it mean that I can take to take even more shots that will overlap each other at least 50%?

the last time when i tried pano, i took only 3 shots or so and it turn out very bad, the distortion and everything, this time round i tried more shots and its much better compared to last time but the main issue became the top and bottom after some correction.

Don't use spherical rotational techniques, but linear pano motion instead. Shoot in portrait mode and avoid very wide lenses.
hi, thanks but I dont really understand what are those techniques metioned above.. when I take the pano shots, I only pann the camera. I suppose that is spherical rotational technique?

what time did you take this picture?
if i remember correctly it was taken between about 6-630 pm
 

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megaweb

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#11
does it mean that I can take to take even more shots that will overlap each other at least 50%?

the last time when i tried pano, i took only 3 shots or so and it turn out very bad, the distortion and everything, this time round i tried more shots and its much better compared to last time but the main issue became the top and bottom after some correction.
If you have a proper pano head gear, yes you can shoot many shots or layers of shots to stitch with minimum distortion. Of course a good software like Realviz Stitcher can stitch and correct the distortion well.
 

Dream Merchant

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#12
hi, thanks but I dont really understand what are those techniques metioned above.. when I take the pano shots, I only pann the camera. I suppose that is spherical rotational technique?
Byteyou,

When you move the camera along a fixed axis (tripod head), you will be rotating it. That induces more distortion than compared to moving the entire lens, camera or tripod in a straight line.

What Megaweb suggested will help greatly, but because special heads are usually very expensive costing hundreds of dollars, many have DIYed these heads very cheaply with great success. http://sg.search.yahoo.com/search;_...&y=Search&fr2=sb-top&fr=yff35-sfp&rd=r1&sao=1

And yes, take many more shots keeping the camera as level as possible to the scene, both above and below the photo ... but in the end, if you keep on adding sky and foreground, you might end up with what looks like a normal wide-angled shot instead of a panoramic shot.
 

night86mare

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#13
This is the shot, im referring to how do i take the picture properly so that when after stitch up, i do not have to crop so much of the sea away (the picture is left with so little "sea" now). Im fine with a little cropping, I understand that sometimes after some correction, you'll have to crop some part off but not like the picture above i got to crop so much "sea" away. Any advise please? thank you :)
you can take a top set of frame

and bottom set of frame to "fill in the blanks"

the problem is that you will end up getting a bit of fisheye effect if you have distinct lines in the picture:

 

night86mare

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#14
And yes, take many more shots keeping the camera as level as possible to the scene, both above and below the photo ... but in the end, if you keep on adding sky and foreground, you might end up with what looks like a normal wide-angled shot instead of a panoramic shot.
well, but with more pixels.

sometimes it is also taken with 10mm at 1.5x crop factor, you are going to get a lot more than what you can get with just single frame, no? :)
 

Dream Merchant

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#15
Actually it would be much easier if TS used an ultra-wide lens that takes in everything that he wants, then crop top and bottom to simulate a pano. :bsmilie:

But not everyone owns a UW or wants to buy one, so stitching with shots taken with lenses with lesser edge/rectilinear distortion would be better - lenses that are less wide is the straight-forward solution if that were the case. If the lense(s) chosen induce barrel distortion (again, usually the wider and ultra wide lenses), there would have to be even more pixel displacement and image degradation during stitching.

But I believe others are more experienced in this area. :)
 

#16
Actually it would be much easier if TS used an ultra-wide lens that takes in everything that he wants, then crop top and bottom to simulate a pano. :bsmilie:

But not everyone owns a UW or wants to buy one, so stitching with shots taken with lenses with lesser edge/rectilinear distortion would be better - lenses that are less wide is the straight-forward solution if that were the case. If the lense(s) chosen induce barrel distortion (again, usually the wider and ultra wide lenses), there would have to be even more pixel displacement and image degradation during stitching.

But I believe others are more experienced in this area. :)
Hi thx for replying, I think sometimes even an UWA lens might not be able to capture all. I tried to take Pano shots and stitch because the widest i can go is only 18mm on a cropped sensor. I'm thinking what if I get a UWA and it still can't capture the things I wanted to then it will be back to the same thing again. Pls correct me if what I thinking is not right..

Thanks for all previous advises as well ;)
 

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night86mare

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#18
Hi thx for replying, I think sometimes even an UWA lens might not be able to capture all. I tried to take Pano shots and stitch because the widest i can go is only 18mm on a cropped sensor. I'm thinking what if I get a UWA and it still can't capture the things I wanted to then it will be back to the same thing again. Pls correct me if what I thinking is not right..

Thanks for all previous advises as well ;)
most times a 10mm with cropped sensor will be able to capture many things in entirety.

the thing is, you do not really want the resultant "perspective distortion" all the time; 10mm can sometimes emphasize the foreground a lot, i.e. make it a lot more significant than it actually is.. this can result in a bad photograph.

you are also right that a uwa might not always be able to capture everything, but it definitely is going to allow you to capture more than an 18mm, and this can be a real boon when it comes to capturing panoramic images that you have to stitch.

for example, this is 4 images stitched together at 10mm.



i can only imagine how many shots you have to shoot to get this equivalent. not even sure if it's possible - it probably is, but requires a lot more work.
 

#19
i can only imagine how many shots you have to shoot to get this equivalent. not even sure if it's possible - it probably is, but requires a lot more work.
You mean to say that to achieve the same result using 18mm would be much harder right? would shooting at 10mm introduce bad barrel effect/distortion that is hard to correct? the picture of the cityscape was shot at 20mm as the barrel effect at 18mm of my lens is pretty bad. At least the last time when i tried it was bad and I find it hard to correct. Its like building at both ends are warping up in a spherical manner.

on a personal note, the cityscape picture i took was inspired by you :)
 

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