Simple Hugin Example with “Wrong Technique”

Sunset over St Andrews Harbour, Scotland. Equirectangular projection 360 deg x 180 deg. Sony A7m3 + Samyang 12mm/2.8 Fisheye, Nodal Ninja 3 Mk III, Capture One, Hugin, and Picture Windows Pro. This is the final stitch without adjustments. Further post-processing steps may include exposures curves, sharpening, saturation adjustment, and eliminating dust spots in the sky.

Source Images & Hugin project file (17MB zip)

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Here is an example of a simple 360 deg panorama in Hugin that shows that good results can be obtained using “wrong” techniques. Specifically, you can use autoexposure, even for highly contrasty scenes that normally would required bracketed exposures and HDR+Tonemapping.

For post-processing, you can crank up the highlight and shadow recovery and individually tweak each frame for exposure. It is not necessary to shoot with manual exposure with each frame with the same exposure settings, nor process them identically.

Additionally, you do not need very much overlap between frames in many cases, only a few control points can do, and they only need to be placed along the seam lines.  A few manually well placed control points can quickly give a good stitch.

This example also shows some other things that you may need to watch out for. You should clean your lens and sensor. I’ve not been able to do much photography lately so my equipment has not been maintained as well as they should have been. My lens also needs to be adjusted as the plane of focus is slightly skewed and it does not reach infinity focus. This is slightly masked by the depth of field at f/8 but can still be detected in the full sized source imagery.

I have provided downsized source images and a Hugin project file if you want to have a look at how it was assembled. I only spent a few minutes putting it together so I’m sure it could be further optimised. The final full sized and processed panorama can be seen at 360Cities. I adjusted the exposure curve, sharpened the image, tweaked saturation, and repaired the dust spots in the sky.

First Shot. I set up my tripod with a Nodal Ninja 3 Mk III. The rotation axes of the panohead is aligned with the no-parallax-point of the lens (it’s not called the “Nodal Point”!). I tilt down to minimise the Nadir hole, bringing in the tripod legs slightly also helps reduce the size of the Nadir patch. I oriented the first shot to capture some bystanders, making sure that they were towards the centre of the frame (don’t want to have anyone cut in half). I also made sure to centre the brightest spot in the sky as I will be patching it with a lower exposure shot. The camera was set to its lowest native sensitivity (ISO100 in this case) and I used autoexposure. The lens is manual focus and manual aperture so the camera controls the shutter speed automatically. I set the lens to be at f/8 and the focus was placed at an approximate “hyperfocal” distance. I used a remote shutter release to minimise vibration. I recorded full uncompressed raw files for later processing.
Second Shot. I rotates the camera by 90 deg using the click-stop rotator on the panohead. For simple scenes, where there are no moving objects, the amount of overlap between frames can be minimal. Here, there is only 10 to 15 deg overlap between the horizontally rotated shots. In more complex scenes, where the could be moving people, cars etc., it may be necessary to take shots in many more different directions in order to produce a stitch with not objects cut in half.
Third Shot. I had also set up the shot so that the main object in the scene (this rowboat) was captured in one frame. This minimises the possibility of any stitching errors occurring on this object. Though the panohead has been aligned to the no-parallax-point, slight shifts due to uneven ground, movement of the tripod as it is rotated, etc., could introduce parallax errors especially with close-up objects. Centering such potential problem areas reduces the possibility of parallax errors happening.
Fourth Shot. We see a small amount of overexposured sky on the right. Hopefully this area will be covered by the extra shot that is exposed for the sky highlights. A belt-and-braces approach would be to take extra shots on either side of the brightest sky areas. This was done but I have omitted this from the example as it is not strictly necessary to illustrate the points.
Extra Shot. This shot was taken by pointing the camera directly at the brightest part of the sky and allowing the autoexposure to control the shutter speed and capture the highlights. Alternatively, the other shots could have been bracketed, e.g. +/-3EV and a conventional HDR+Tonemapping process applied. Here, we show that a much faster and simpler process can produce acceptable results without the extra shots and processing. The wide latitude of modern cameras reduces the need for bracketing and raw processors are very good at extracting highlight and shadow detail.
Zenith Shot. This is taken pointed straight up. In order to position it in the final panorama, I have included a few features in the corners than can be used to locate it via control points. As there are no important features in the sky, it is not important to precisely align it with the other images, hence it could be manually positioned in a pinch.
Nadir Shot. I have a Nadir Adapter on the Nodal Ninja 3 Mk III panohead that allows the taking of the straight down shot very easily. It also provides extra vertical rail height to allow the A7m3+12mm/2.8 combo to rotate to Zenith easily.
Masking Source Images. The tripod and corners are masked off first. The corners often suffer darkening due to vignetting, masking them off can improve photometric optimisation and matching. The overexposed sunset sky is also masked off and will be replaced by a separate shot that is exposed for the sky. This was taken by just pointing the camera straight at the brightest point in the scene and allowing the autoexposure to set the shutter speed to capture the highlights. The Zenith and Nadir images are also given a circular crop.
Adding Control Points. Only a few control points (CPs) are required to get a good stitch if the rotation axis is well aligned with the entrance pupil aka no-parallax-point (NPP). Some of the images pairs have 4 CPs, some only 2, and a few have more. It is only necessary to place the CPs long the likely seam lines of the final stitch. Placing CPs away from the seams means that alignment is compromised in the regions where alignment errors are actually visible. A few well chosen CPs will give better results than heaps of widely spread CPs that may have mismatched features. NB: The NPP is often erroneously called the “Nodal Point” but the entrance pupil does not in fact correspond to any of the (several) nodal points of a lens (look them up on Wikipedia). It’s like calling the steering wheel a “tyre”, they are both round and are parts of a car, but they are not the same thing.
Preview Window. This is how the aligned images are placed, green crosses show the location of the control points. The small exposure differences will be eliminated during the stitching and blending process. The panorama is exported at a reduced exposure so that the highlights are not blown out. Exposure range compression can be used to bring back shadow detail. Curves adjustment in post-processing can then equalise the exposure to obtain a pleasing image.