Photos won't stitch, anybody know why?

[arith]

I've tried to do it manually, a spot of painting, everything. Is it because I am too close or is it the cheap lens or what is it?

[KentDub]

Are you trying to do a pano? Can you post each image individually?

[McQ]

It's hard to say without seeing the original images, but if I had to guess I'd say that you're having issues with parallax error in the stitched panorama (the benches are too close to the camera, and/or the camera is not rotating about it's optical center).

[Colin Southern]

What program are you using? How much overlap is there between images? Are you entering the correct focal length (allowing for any crop factor?).

[arith]

What program are you using? How much overlap is there between images? Are you entering the correct focal length (allowing for any crop factor?).

Yes it is four images. The lens is 28mm and I'm saving for a better one, the tripod I think isn't straight because every image has to be rotated the same amount. The spirit level says it is straight but I think the panning head isn't.

It is a shame really.

[arith]

Sorry, three images it is the other side that was four and that doesn't stitch at all.

[arith]

It's hard to say without seeing the original images, but if I had to guess I'd say that you're having issues with parallax error in the stitched panorama (the benches are too close to the camera, and/or the camera is not rotating about it's optical center).

I like the tutorial, never heard of nodal point but I think that is what is wrong.

[McQ]

This is definitely parallax error. If you look at the benches, the perspective of the two rows closest to the camera changes substantially between photos (in the overlapped region). This will make it pretty difficult for stitching software to align.

The best thing to do is to re-take the images where you are either (i) much further away from the benches, (ii) are using a panoramic head on a tripod, or (iii) using a new composition which excludes the benches and other foreground objects entirely. If you cannot retake the images, you'll need to try and manually blend the images using a layer mask (once they've been corrected for perspective, distortion, etc). You can also try using SmartBlend for the stitching program PTAssembler. In select situations, SmartBlend can intelligently blend around objects that are causing parallax issues. However, in your case I don't think it will work since the benches extend into every single individual photo. Potentially still worth a try though...

PS: I am moving this thread over to the image processing forum since it's become a lot more about stitching than about HDR photography

[arith]

Cheers McQ; it just means I can't do close up panorama which is a shame, I wanted that view since it is where I sit on Sunday.

Never mind when I get a beeter lens I can take it all in one go.

[arith]

I just thought; I have a close up pano that did stitch already displayed in this forum, I can't show it here because fotki have made it non downloadable.

It must be because the head was turned on its side and so when I get a wider lens I should be ok.

So here is looking forward to Christmas, when I will buy myself a new present.

[willgoss]

Well,I don't know what "wont stitch" means but......the 3 images stitched for me it Autostitch and in Microsoft ICE.....

[arith]

Well,I don't know what "wont stitch" means but......the 3 images stitched for me it Autostitch and in Microsoft ICE.....

I used autostitch!! The table is broken when tried; but what is SIFT and RANSAC? Hope I got that right it doesn't mean a thing and altering them made no difference.

When I tried in GIMP I could get even blending spot on, the benches aligned and the top; but the middle was out. I'm not an expert so I gave up.

[willgoss]

Well, I didn't say they aligned well.....but they stitched without complaint.....the center panel is slightly out of alignment as well as darker....as discussed previously ....

[Dave Humphries]

Hi Arith,

I've never tried this in my life, but I have read the digital panorama tutorials (a while back). That link is to the first of 3.

How about trying two columns of 3 landscape orientation images, rather than 5 or more portrait orientation ones in a single horizontal pan (the almost classic 'panorama'). I think it might stitch more succesfully.

Just an idea - and please accept my apologies if you've already read the tutorials.

[arith]

Hi Arith,

I've never tried this in my life, but I have read the digital panorama tutorials (a while back). That link is to the first of 3.

How about trying two columns of 3 landscape orientation images, rather than 5 or more portrait orientation ones in a single horizontal pan (the almost classic 'panorama'). I think it might stitch more succesfully.

Just an idea - and please accept my apologies if you've already read the tutorials.

I have read it; and your right. But when I get a 17mm good lens I might be able to get the windows in. Then not only would I need only three for the whole lot but lower parallax problems and less straight line issues.

I hate turning the camera on its side because it greatly increases the complextity of the shot; in this case 4 for the right hand side and three for the left 6 altogether, of course a big overlap and I didn't intend using all of them.

[Colin Southern]

Hi Arith,

A quick primer on Nodal points ...

When you rotate the camera using the sensor as an axis the relationship between things in the foreground and background changes. You can see this for yourself if you do a little test:

- setup the camera on a tripod and on the left hand side align something in the foreground with something in the background (say, the edge of a table with the leg of a chair).

- Now rotate the camera do that the two things that you lined up are now in the right hand side of the view finder - you'll see that they're no longer lined up.

What you need to do (dead easy in theory, but much harder in practice) is to ensure that the camera rotates around the end of the lens (where the light enters), not around the sensor. In other words the front element of the lens needs to be over the centre of the tripod - then things stay in alignment and they'll stitch correctly.

HOWEVER - none of this means that you won't get distortion in the final shot. In wide-angle shots this is unavoidable because you're trying to map a 3D object onto a 2 dimensional surface, and "something has to give"

Hope this helps!

PS: Easiest way by far is to just use an extremely wide angle lens!

[arith]

Cheers Colin. I hope to use a wide angle lens in a month or so but in the meantime I will try to ensure near objects are not near stitching points. In this case I didn't really expect it to stitch more hoped it would and got really excited until the fourth frame, right to left.

I wanted to do a really good job since the vicar said I could take as many photo's as I liked but the Church Warden looked a little bit put out I had an hour and he was there asking how much longer it was going to take.

[KentDub]

Hi Arith,
What you need to do (dead easy in theory, but much harder in practice) is to ensure that the camera rotates around the end of the lens (where the light enters), not around the sensor. In other words the front element of the lens needs to be over the centre of the tripod - then things stay in alignment and they'll stitch correctly.

Are there any tripod accessories that can do this? (Such as a horizontal bar that the camera can slide on -- and of course lock down). Although it would sacrafice a lot stability, a counter-weight could do the trick to get it to pivot like that...

[Colin Southern]

Are there any tripod accessories that can do this? (Such as a horizontal bar that the camera can slide on -- and of course lock down). Although it would sacrafice a lot stability, a counter-weight could do the trick to get it to pivot like that...

Yes. I use a nodal bar and panning clamp from Really Right Stuff. Point your browser here

PS: For those of you who aren't familiar with Really Right Stuff stuff, it's really good quality - works really well - looks really good - and is really expensive. I love it.