Lightroom Photo Merge Disappointment

Nantes Cathedral, RX10 4 image vertical stitch
Nantes Cathedral, RX10 4 image vertical stitch. Click the image to see the enlargement.

If you have ever tried to produce a vertical stitch panorama you will know that it’s very difficult when there is a tall building involved. The problem of converging verticals is always present but at you tilt the camera at different angles for each frame in the stitch, the angle of convergence changes. This makes stitching everything together quite (actually very) difficult.

What I had wondered is if the new Lightroom Photo Merge stitching would be any better. Unfortunately it wasn’t.

My first attempt looked as though the image was bending out in the centre and then tilting over backwards. It’s then I had the idea to correct the vertical tilt on each image separately before trying to merge the images together. And that’s my disappointment. All the adjustments are ignored and you end up with exactly the same result. You therefore need to manually correct (or try to correct) the finished image.

This example isn’t too bad but with others there is a lot of distortion that is just too difficult to fix. Despite the distortion I do like the finished image. It’s also very large at 11″ x 31″ and very sharp.

11 thoughts on “Lightroom Photo Merge Disappointment

  1. This image is imminently acceptable in technical terms, but not architecturally because it’s not wide enough to show the entire portal arch. I think it would have worked better from a somewhat greater camera-subject distance, shot from a ladder in order to see the bottom of the doorways. I almost always shoot tall buildings from a ladder anyway, because it significantly reduces convergence and helps to preserve the proportions without so much WA lens “stretching.” That’s not easy to do if you’re traveling, but it may be possible to rent a ladder for a day’s shoot. As for convergence, I don’t understand why complete correction in each segment is not possible prior to stitching. That probably would require different resizing as greater convergence correction mandates progressively more cropping in the upwards segments. Inevitably, the clerestory windows would appear vertically stretched, so in fact the result you have achieved here is more pleasing and the minor convergence toward the top does not detract at all from the visual effect IMO.

    1. Hi John, the points you are picking out about the image are the same reasons that the merge function is disappointing me. Had I used a dedicated merging program I could have addressed a lof of these problems. Indeed conrting the images and then merging in Photoshop is a much better option. Trying to correct the problems in the merged DNG afterwards is next to impossible. Yes I could have addressed some of these issues by changing my position but I wanted to see how the merge program handled these. I do agree with you though that minor convergence works better for images where you are positioned close to a tall subject otherwise it looks unnatural.

  2. Interesting, I have tried the horizontal pano merge option and been very happy with the outcome. I havent shot any verticals so can’t test it but I understand about the different issues with the tilt and other distortion that can be a problem with architectural images.

    The one you presented does have some slight issues but for the majority of people they would never notice. Like the first commenter, the biggest problem is the arch is chopped off and we cant fully appreciate its magnificence 🙂 I had to learn the hard way to shoot buildings with much more frame around them to account for the adjustments that LR does when it fixes them.

  3. I have not tried this but just had a thought.
    Its more work than should be required but can you re save your shots after straightening (which should lock in the changes made) and then merge them in LR ?

    1. Your quite right that if I create new files with the changes applied the merge works correctly on the new versions. The only problem for me is that its just as easy to take the files into a dedicated merge program for better results. Never mind, I still like the horizontal panoramic results.

  4. I use Autpano Pro which handles verticals quite well. However one other issue you didn’t mention is that as you take the upper images, because the lens’s angle of view is constant, a progressively wider portion of the structure is included. This is the real source of the distortions, more so than the keystoning effect of perspective. We are used to seeing this in horizontal panoramas – as curves – but not in vertical ones, where we “want” to see verticals as nearly straight. One way of minimising this is to use a longer lens from further away. Interior vertical panos are even more difficult to render in an acceptable way, unless you accept considerable distortion.

    1. I agree wit your point that a progressively wider potion of the image is being revealled but it should still be able to stitch. I still feel the problem is coming from the angle of the camera as the angle of tilt is increasing with each subsequent shot and I am not tilting around the cameras nodal point. This is an example of where a tripod and panoramic head would come in handy. The tilting angle once processed seems to make the centre of the image appear to bulge out once processed. The auto crop then over crops. In any case, it’s no substitute for a dedicated stitching program such as Autopano Pro. I had forgotten all about that software and you also reminded me that I used to use Panorama Factory. I must dig out my license key. Spot on about using a longer lens but I was trying to stress the software (which I think I did).

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