High Rise

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    Topic: High Rise Read 265 Times
  • Chris Kern
    Chris Kern
    Participant
    Posts: 59
    Adobe Lightroom & Adobe Camera Raw
    on: July 22, 2023 at 6:12 pm

    This already may have been obvious to many of you, but it just occurred to me today that Lightroom’s Photo Merge feature might be capable of producing a vertical pano.  The attachment is a stitch of three handheld shots of a building under construction in Bethesda, Maryland, a small city (well, Wikipedia calls it an “uncorporated place”) just north of Washington, D.C.  The keystoning in this composite is admittedly egregious—well beyond the limits of any reasonable correction—because I couldn’t move any farther away from the building to get a less distorted view.  But clearly the orientation of the stack doesn’t adversely affect Lightroom’s ability to combine the component images.  I’m trying to wrap my brain around the geometry necessary to compensate for this with a tilt-shift lens, although I suspect merging the individually-corrected photos would either be impossible or the parameters would be so complex as to defy my meager mathematical skills.  (In any event, I don’t possess a tilt-shift lens.)  However,  I’m not sure adjusting the perspective really is necessary for this kind of neck-craning picture.

    verticalPano

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    Mark D Segal
    Mark D Segal
    Silver Member
    Posts: 951
    Re: High Rise
    Reply #1 on: July 22, 2023 at 8:33 pm

    I’ve been making these for some years now and they can be tricky. What I find works best is to keep the camera in landscape orientation, which requires you to make more photos than if it were in portrait orientation. In fact, you want to provide for substantial overlap between the shots. Use as wide an angle as your lens will permit. Between this and the landscape orientation you should have lots of space on either side of the building, and it will increase as you aim higher. This is necessary for the next steps. It is preferable to put the camera on a tripod and make sure the camera is truly level. Take all your exposures into Lightroom and select enough of them to provide at least 25% overlap on top and bottom of each photo. Do the Photomerge, the only option likely to work being “Perspective”. When it finishes you will have a heavily keystoned photo. You correct this by using the Lightroom <Upright > control on the left and right edges of the building. This will shed most of the material on the sides and keep the merged main subject looking straight.

    Chris Kern
    Chris Kern
    Participant
    Posts: 59
    Re: High Rise
    Reply #2 on: July 23, 2023 at 12:03 pm

    I’ve been making these for some years now and they can be tricky. What I find works best is to keep the camera in landscape orientation, which requires you to make more photos than if it were in portrait orientation. In fact, you want to provide for substantial overlap between the shots. Use as wide an angle as your lens will permit. Between this and the landscape orientation you should have lots of space on either side of the building, and it will increase as you aim higher. This is necessary for the next steps. It is preferable to put the camera on a tripod and make sure the camera is truly level. Take all your exposures into Lightroom and select enough of them to provide at least 25% overlap on top and bottom of each photo. Do the Photomerge, the only option likely to work being “Perspective”. When it finishes you will have a heavily keystoned photo. You correct this by using the Lightroom <Upright > control on the left and right edges of the building. This will shed most of the material on the sides and keep the merged main subject looking straight.

    Good point about using landscape orientation to capture the components of the stitch.  I didn’t think of that when I was shooting my initial test yesterday, but it’s analogous to the way I make horizontal panos.  For those, I shoot a series of pictures in portrait orientation in order to have plenty of image area for the subsequent crop.  Makes sense to use landscape orientation for a vertical pano.

    As for adjusting the perspective afterwards, there are limits to how much you can warp an image in post without excessively distorting the proportions of the subject.  These become especially significant when the subject is a building or a cityscape.  If you’re too close—as I was when I made the captures that I combined to produce the image above (I had my back up against the wall of another building so I couldn’t move farther away)—adjusting the verticals to be anywhere near parallel will stretch the top of the subject to an extent that is too unnatural to be acceptable.

    Perspective correction in software works best when only a minimal vertical warp of the image is necessary.  Even then, when shooting architectural subjects I often find it desirable to allow a very small amount of keystoning to remain: just enough to encourage the viewer’s eye and brain to interpret the subject’s height correctly while still seeing the verticals as parallel.

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    Mark D Segal
    Mark D Segal
    Silver Member
    Posts: 951
    Re: High Rise
    Reply #3 on: July 23, 2023 at 12:26 pm

    Yes, there are limits for the reason you state, but depending on the image and the extent of the keystoning that needs correction, there can be quite a bit of tolerance before the result becomes unnatural; I find it always best to experiment. In these situations I’ll make more captures than necessary knowing that a lot could be thrown out. As for the limits, I’ve attempted 20-storey buildings in tight spaces (akin to your example above) and I find it’s too much for this technique to work well – by the time one gets to the upper-most stories image quality is poor. As a general guideline, I think once one gets beyond 10-12 stories with a lot of angling, it becomes quite dicey.

    Kevin Raber
    Kevin Raber
    Silver Member
    Posts: 1305
    Re: High Rise
    Reply #4 on: July 25, 2023 at 8:05 pm

    don’t forget you could also do multiple rows or columns when shooting a pano.  Once the pano is made you can then try to do perspective correction.

    Kevin Raber
    Owner and Publisher of photoPXL

    Mark D Segal
    Mark D Segal
    Silver Member
    Posts: 951
    Re: High Rise
    Reply #5 on: July 25, 2023 at 8:12 pm

    don’t forget you could also do multiple rows or columns when shooting a pano. Once the pano is made you can then try to do perspective correction.

    That can work well for scenes without both high degrees of keystoning and a large distance between bottom and top.

    Chris Kern
    Chris Kern
    Participant
    Posts: 59
    Re: High Rise
    Reply #6 on: July 26, 2023 at 11:35 am

    don’t forget you could also do multiple rows or columns when shooting a pano. Once the pano is made you can then try to do perspective correction.

    That can work well for scenes without both high degrees of keystoning and a large distance between bottom and top.

    I’ve never tried to make a rows-and-columns pano (matrix pano?), but I suspect that approach is better suited to a deliberative, on-the-tripod methodology than the rough-and-tumble, shoot-from-the-hip, handheld panos I create when the subject I want to capture doesn’t fit within the frame of the lens I’m using and I can’t move farther back.

    I also suspect—this is based on conjecture, not experiment—that cleanly stitching a composite image composed of rows and columns is more likely to be successful with a cylindrical or spherical projection than a projection that attempts to preserve the straight lines and proportions of a subject such as a tall building.

     

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    Jeremy Roussak
    Jeremy Roussak
    Gold Member
    Posts: 1041
    Re: High Rise
    Reply #7 on: July 27, 2023 at 6:06 pm

    I’ve never tried to make a rows-and-columns pano (matrix pano?), but I suspect that approach is better suited to a deliberative, on-the-tripod methodology than the rough-and-tumble, shoot-from-the-hip, handheld panos I create when the subject I want to capture doesn’t fit within the frame of the lens I’m using and I can’t move farther back.

    I’m not sure that’s right, Chris. I’ve done a few hand-held, on-the-fly “matrix” panos and I find they stitch pretty well. Here’s a 3×3 pano I took in 2010. I’d process it differently now, but the stitching worked very nicely.

    pxl-4

    Jeremy

    Mark D Segal
    Mark D Segal
    Silver Member
    Posts: 951
    Re: High Rise
    Reply #8 on: July 28, 2023 at 9:16 am

    It’s good Jeremy.

    Chris Kern
    Chris Kern
    Participant
    Posts: 59
    Re: High Rise
    Reply #9 on: July 28, 2023 at 11:33 am

    I’ve done a few hand-held, on-the-fly “matrix” panos and I find they stitch pretty well. Here’s a 3×3 pano I took in 2010. I’d process it differently now, but the stitching worked very nicely.

    Yes, that looks fine to my eye—although I think it’s relevant to this thread that because of the chateau’s island location, you were able to shoot from far enough away to avoid the extreme perspective distortion that is present when a camera is pointed up at a tall building from a position close to it.

    I wouldn’t be surprised if some dedicated applications for creating panoramas are able to do a better job than a general-purpose application such as Lightroom in performing difficult stitches.  I’d never heard of Kolor Autopano, but I briefly experimented with a trial version of PTGui and was favorably impressed with it.

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    Jeremy Roussak
    Jeremy Roussak
    Gold Member
    Posts: 1041
    Re: High Rise
    Reply #10 on: July 28, 2023 at 12:25 pm

    Yes, that’s a fair point. Autopano Pro is no longer supported, which is a shame as I rather liked it. (As usual, I went for the Betamax choice, rather than getting to know PTGui). I now stitch in Lightroom, which does a remarkably good job of both single and multi-row panoramas. I posted this image only to make the point that, luckily for me, multi-row panos don’t necessarily require much expertise.

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