I. For some time now I’m engaged in panoramic photography. In the beginning I only worked with multi-row 2D-images, now I’ve shifted my interest to spherical 360° panoramas also known as Photospheres.
Generally a Photosphere can be created with any gear but there is only one setup that really works and is feasible. On a sidenote I’d like to mention the new development of proprietary 360° cameras. Those are mainly intended for panoramic video and have certain shortcomings, for example the photographer/videographer will be in every Photosphere or videosphere and it is not possible to wait for passersby to leave the area. Also, the resolution is much lower.
Thus I will present my setup for creating Photospheres. Basically you need to take enough single images to fill a 360° sphere. As mentioned before you can do this with any gear but in some scenarios you would need several dozens of images which is both extremely cumbersome and error-prone.
The optimal gear is a full-frame camera (also known as 35mm format, that’s about 36x24mm sensor-size) with a circular fisheye lens with a focal length of 8mm. With this combination only four (actually it takes only three, see below) images are sufficient for stitching a Photosphere. Some people tend to take two additional shots, the so called nadir (floor) and zenith (sky) images. I’ll come to that later.
There are two types of fisheye lenses; they differ in their projection type. There are circular and diagonal lenses. You can use both for panoramic photography but circular fisheyes lenses have a greater coverage and thus are preferable. Diagonal fisheye lenses are better suited for certain types of 2D-architectural photography because those don’t suffer from the “typical” fisheye distortions. It would be wrong to say one projection type is better than the other, it’s just that they are each better suited for certain needs.
A circular fisheye lens with a focal length of 8mm has a coverage of about 180°. One might think two images would be sufficient for a 360° panorama. That is not wrong but without any overlap it’d be very hard to stitch the panorama and there are other problems. I don’t want to digress here so I’ll continue with the standard setup.
The next thing you need is a stand for the camera, optimally a tripod. Monopods are also possible, I’ll come to that later.
Always keep the eye level in mind. For indoor photography like real estate advertising you should not go higher than 180cm (floor to center of the lens), better around 160+ cm, otherwise it’ll look like a giant took the images.
Outdoors it’s different. Usually the subject will be at greater distances than in a closed space. Therefore you should aim higher. For certain architectural subjects like churches or towers or when in relative close distance to buildings you should consider going much higher. This requires a special kind of tripod, the so called “super high tripod” (not very ingenious, I know). Those can be as tall as several meters.
Alas, then you will encounter another problem: How to set up the camera and how to turn it. Short answer: Use a ladder. Understandably, that’s very cumbersome and looks utterly unprofessional. In my opinion the only sensible way to use a super high tripod is with a motorised so called “nodal point adapter” or “no parallax adapter”. Those are very expensive (ranging from EUR 1.500,- to 20.000,-) and go far beyond the scope of a hobby.
Therefore, let’s continue with the usual setup and procedure:
II. As mentioned before only four images are sufficient for stitching a Photosphere. For a 360° sphere that means you have to take an image every 90°. And I mean 90°. Some lenses have a little leeway of 2-3°, others don’t. Therefore you should ascertain an accurate turn.
That leads to another part of necessary gear: The panoramic head. This one’s a misnomer in my opinion because there are different meanings. I only mentioned it for reference.
For mounting the camera in the correct position the aforementioned “nodal point adapter” or “no parallax point adapter” is indispensible. The nodal point adapter enables turning the camera around the “no parallax point”.
The most time-consuming part (albeit a one-time effort) is to set-up the nodal point adapter. Just one millimeter off will result in so called parallax errors. The severeness of those increases the closer the camera is to the subject. You would see those errors at once on a tiled floor for example.
The adapter needs to be mounted on a rotating base, often called panoramic plate (more below).
That plate must be mounted on a levelling base. A levelling base is not absolutely necessary but without one you would need to adjust the length of the legs of the tripod in order to level it – and that’d be well-nigh impossible and extremely time-consuming. In short: You want to have a levelling base.
As a levelling base you can use a geared head, a ball head or a levelling center column. I use the last one. It’s light and very quickly and exactly adjustable. Ball heads are more cumbersome to adjust, I advise against them. A geared head would be the most exact solution but it’s heavy and takes time to set up. Also, I never encountered a situation where a levelling center column wasn’t sufficient (We are talking about 100% compared to >95% accuracy.). The levelling is the one setting that does not need absolute accuracy.
The easiest way to control the set-up is to create a Photosphere and look at the bottom where the tripod is. You should see a perfect cross, otherwise you’ll need to adjust and try again.
III. Provided you’ve mounted your perfectly adjusted nodal point adapter on your level tripod you can start taking pictures at 90° (resp. 120° with three images) steps. The panoramic plate or rotating base has a scale for this purpose. There are also indexed rotating bases like the one I use. I’ve set it to 45° (resp. 60° with three images) so I need to rotate just two clicks for every image.
I mentioned before some people also take nadir and zenith shots. I do not. I mount the camera with a slight inclination so there is no need for a zenith shot. At the floor you always have the problem of the tripod being in the picture. You can take a nadir image and manually stitch that into the sphere. Quite bothersome, therefore I don’t do that either because I just insert my logo with copyright notice in that spot.
Until now I’ve only spoken of tripods. It’s also possible to use a monopod. Using a simple monopod prevents exact rotations in 90° steps, though. Therefore I use the MVA50A Fluid-foot for my Manfrotto® 680B monopod. That provides the exact same rotating accuracy like a tripod. The one thing you can’t do is long exposure because that setup is too fragile. Levelling is also not as accurate as with a tripod but as said before that one doesn’t need to be perfect.
Another advantage of tripods is the possibility of exposure bracketing. I rarely use that because modern cameras, especially from Sony® and Nikon®, have a vast dynamic range. Just set it to ISO 50, expose mainly for the sky and you’re good.
For the sake of completeness there is a very low budget solution: The Philopod. Basically you substitute the tripod/monopod with a plumb line. It’s named after Philippe Hurbain.
For taking images for Photospheres the camera must be set to “manual”, all images must be taken at the same aperture and ISO. The same is not 100% true in regard to exposure but generally it should be fixed, too.
Contrary to other people I use automatic white balancing because I exclusively shoot RAW and synchronise that in post processing, it’s more exact and much faster.