Pano mushroom top

[gdavis]

My first attempt at star photography.  Not a very good night for it but at least I got something to experiment with.

Any idea why the top of my panorama gets stretched out like this?  Is this normal?  There are two rows of shots, but even if I just take the top row it stretches out the same.

Full frame camera with 24 mm lens on a nodal ninja tripod bracket in portrait orientation.

[Callum]

Hi Gdavis,

Welcome to the forums

If possible could you provide he images that make up this panorama.

Thanks

Callum

[gdavis]

Here are the individual images.

stack1.tiff

stack2.tiff

stack3.tiff

stack4.tiff

stack5.tiff

stack6.tiff

stack7.tiff

stack8.tiff

stack9.tiff

stack10.tiff

[John Rostron]

I think that your panorama comes out the way it does is because your upper row of images has been taken with your camera pointing upwards, as compared with the bottom row. Thus there is an intrinsic perspective distortion in these images. I downloaded your images and created two panoramas, one with the top row and one with the bottom row. The bottom row generated an approximately rectangular panorama, as expected. The top row produced the same distortion as seen in your image, probably for the reasons I mentioned. I did try and merge these two panoramas into one, but it would not play!

There are various possible solutions. One would be to create five small, tall panoramas, each from two images in the same horizontal position. I tried this with your first and sixth images, but I was told it could not find a panorama. I was assuming that the second five images (6-10) matched the first five (1-5). Do they? If not, how do they pair up? If you can create these five images, then you could try to merge them into one panorama.

An alternative approach (and I am speculating wildly here) would be to 'correct' the perspective distortion in the top five images using the mesh warp to compress the top part by (say) 20-30%. You could then try to merge all ten.

Failing all that, you could use the mesh warp tool to correct your mushroom!

John

[gdavis]

Thanks for the reply, John.

9 hours ago, John Rostron said:

I think that your panorama comes out the way it does is because your upper row of images has been taken with your camera pointing upwards, as compared with the bottom row. Thus there is an intrinsic perspective distortion in these images.

This thought occurred to me also, I just can't figure out how this would be a sensible or useful way to handle it.

9 hours ago, John Rostron said:

I downloaded your images and created two panoramas, one with the top row and one with the bottom row. The bottom row generated an approximately rectangular panorama, as expected. The top row produced the same distortion as seen in your image, probably for the reasons I mentioned. I did try and merge these two panoramas into one, but it would not play!

I tried the same thing with the same results.  I think the top row and bottom row, when stitched separately, are scaled differently so they can't be merged back together.

9 hours ago, John Rostron said:

There are various possible solutions. One would be to create five small, tall panoramas, each from two images in the same horizontal position.

I'm afraid this will suffer the same problem as doing the two rows first.

9 hours ago, John Rostron said:

I was assuming that the second five images (6-10) matched the first five (1-5). Do they? If not, how do they pair up?

I went left-right for the bottom row and right-left for the top row, so the pairs would be 1/10, 2/9, 3/8, 4/7, 5/6.

 

9 hours ago, John Rostron said:

An alternative approach (and I am speculating wildly here) would be to 'correct' the perspective distortion in the top five images using the mesh warp to compress the top part by (say) 20-30%. You could then try to merge all ten.

Failing all that, you could use the mesh warp tool to correct your mushroom!

Ya, thought about that too, but seems tricky to warp it just right to exactly "correct" the flaw.  And compressing it before merging to compensate for the stretching that will be applied is going to degrade the image quality and defeat the purpose of multiple images.

At this point, I'm not really looking for a way to kludge together a half way decent result.  More looking for an answer like - this is normal because the algorithm used is just not applicable for what I'm trying to do and I need to use another program - or - they'll add algorithm options in the future that will work - or - it's not functioning as intended and it needs to be fixed - or - You're doing it totally wrong, here's how to do it - or - something like that.  If AP just doesn't support doing what I'm trying to do and I need another program or my approach is wrong, I can accept that, I was just having a go at it with what I have on hand and was puzzled by the result.

[John Rostron]

4 hours ago, gdavis said:

At this point, I'm not really looking for a way to kludge together a half way decent result.  More looking for an answer like - this is normal because the algorithm used is just not applicable for what I'm trying to do and I need to use another program - or - they'll add algorithm options in the future that will work - or - it's not functioning as intended and it needs to be fixed - or - You're doing it totally wrong, here's how to do it - or - something like that.  If AP just doesn't support doing what I'm trying to do and I need another program or my approach is wrong, I can accept that, I was just having a go at it with what I have on hand and was puzzled by the result.

I had a try with your images using Autopano which has given me good results in the past. However the overall results have been much like as in Affinity. I also tried some pairings 1/10 and 5/6. In each case I was told 'No panorama detected' implying that it could not find sufficient points of comparison. You might like to try the free stitcher Hugin. I have found that this has been effective in the past.

John

[firstdefence]

What about using the lens @ 35mm or even a 50mm instead of a 25mm and taking a wider vista.

or

If you have to use a 25mm take a wider vista to accommodate for the "wingage" < made up word lol! and crop to the image you wanted.

You could also step back a bit, say 40 miles or so 

[firstdefence]

Had another look at this and tried using AutoGiga Pano (AGP). See screen shot below for a few results.
AGP actually separated your images into two different pano's, the one with just sky and the rest with the land mass, when trying to apply all the images to a grid it crops the land mass off.
AGP see's each pano as a different environment which I guess is where the problems start.

This is the Render from the middle pano scaled down a bit.

[John Rostron]

7 hours ago, firstdefence said:

Had another look at this and tried using AutoGiga Pano (AGP). See screen shot below for a few results.
AGP actually separated your images into two different pano's, the one with just sky and the rest with the land mass, when trying to apply all the images to a grid it crops the land mass off.
AGP see's each pano as a different environment which I guess is where the problems start.

This is the Render from the middle pano scaled down a bit.

This is more or less what I got in Autopano.

John

[gdavis]

Thank you both for checking this out.  This feedback is leading me to the conclusion that something is wrong with my images / procedure.

I tried manually lining up 1 and 10, and when I line up Mars, everything else is way out of whack.  Maybe I bumped the zoom or something.

I had actually intended to use 50mm initially, but when I got there it just seemed too narrow a FOV and didn't want to have to do that many photos.  I'd seen people doing 360 with wider lenses and fewer shots so I didn't think it would be a problem.

I guess I'll have to try again with an easier landscape until I get this figured out.