How do I adjust the panoramic head?
The first step is to determine where the nodal point of a particular lens model is located. The location of the nodal point differs from lens to lens. You can calculate the position of the nodal point of your lens with a little experiment.
First adjust the intersection of the optical axis of the lens and the rotation axis.
Mount your camera on a panoramic head and a tripod.
Rotate the camera with the lens level down so that the tripod is in the frame.
Move the camera so that the rotation axis is exactly in the center of the viewfinder.
Most panoramic heads have a special “target” on them to make this process easier.
Let’s proceed to find the nodal point
- Place two objects (e.g. pencils) in front of the camera, exactly in the center, one after the other. Take the first picture.
- Then turn the panoramic head to the left so that the pencils are at the right edge of the frame. Take the second picture.
- Now turn the camera the same angle from the original position to the right. The pencils will be on the left side of the frame. Take the third shot.
Since the panoramic head is not yet adjusted, you can notice that in the left and right shots the pencils are shifted relative to each other. This is the parallax effect. If it is neglected, it will be impossible to glue the panorama from the obtained photos.
Now we have to find the nodal point. Turn the camera to the left as on the second step. Move the camera on the rung of the panoramic head back and forth. At the same time, keep an eye on the position of the objects in the frame. When both pencils will line up in one line, i.e. the front one will overlap the far one, this will be the most cherished point. Now, when you rotate the camera in any direction, there will be no parallax.
Find nodal point for your lens model
The nodal point value for many lenses is already known. There is a special table with the necessary parameters of lenses and cameras. Therefore, the whole process is greatly simplified. You just need to calculate the length of the segment according to the formula:
- a – distance from lens base to nodal point;
- b – distance from the camera mount to the lens base.
When the segment length L is known, the only thing to do is to set it on the panoramic head scale and fix the position.
Adjusting the rotation step of the panoramic head
Determine the angle, by which the camera will be fixed during each rotation. This is directly related to the angle of view of the lens and sensor size. Keep in mind that the overlap of neighboring images should be 20-25%. This is the minimum value, in some cases it is more reliable to increase the overlap to half of the frame (50%).
Examples of rotation angle:
- Cropped factor 1.6 and focal length 18 – step 30° (shooting in 3 rows of 12 frames)
- 1.6 focal length with a 10 focal length – 60° step (2 rows of 6 frames)
- 1/3 focal length with a 12 focal length – 90° spacing (1 row, 4 frames)
Many panoramic heads have a rotator that adjusts to the desired angle of rotation.
Tripod and level
With a level platform, setting the horizon is easy enough. You change the tilt of the base until the bubble in the level is centered.
If you don’t have a level base, the tripod will help you adjust the horizon. To do this, change the length of the tripod legs and set the desired tilt. In this case we use the bubble level as a reference.
Setting up the camera and the lens
As a result, we will get several frames, which will be combined into one panorama. Each photo should have the same exposure, color, sharpness, etc. That is why only manual mode is used for panoramic photography.
- We choose the quality of the pictures – RAW.
- Set the mode to Manual (M). You cannot change the exposure value of your images. This will make things much more difficult in the future.
- We close the aperture to the value of F10-12 and set the shutter speed according to the surrounding light.
- The sensitivity value (ISO) should also be fixed.
- Set the auto bracketing mode. Select Continuous Shooting and Exposure Step 2.
- Select the exact value of white balance (if the settings allow).
- Focus on the desired object, after which auto focus must be switched off.
The process of shooting 360 panoramas
Shooting 3D tour starts with the selection of shooting points – places where the tripod will be set up. Navigation through the virtual tour is easier when there is a direct line of sight between adjacent 3D panoramas.
When all equipment settings are made (see above), the only thing left is to take a 360 degree panoramic photo. Take the first frame, then rotate the panoramic head by a given step and take the picture again. And so on until all parts of the future circular panorama are ready. To avoid confusion, you should start at 0° and rotate clockwise. Once you get back to the starting position, you can proceed to the next row. As a result, we get the following set of photos:
Next, we take pictures of the zenith and nadir. To do this, point the camera up and down.
If you take a photo of the nadir (bottom) from the panoramic head, you will have a tripod in the photo. There are two ways to remove it:
Using a graphic editor. If the nadir contains uniform elements (tiles, parquet, grass, asphalt, etc.), it won’t be difficult to correct it in Photoshop.
Take a picture of the nadir without a tripod and insert it during the gluing of the 3d panorama. To do this, you can use a tripod in a folded state or just take a picture on an outstretched arm. In both cases, you should try to bring the camera closer to its original position. This method is especially necessary when there is a pattern or design element on the floor.
Rules for successful shooting
- Avoid reflections. When taking pictures, the photographer might encounter obstacles in the form of mirrors or glossy surfaces. It is worth paying special attention to this. It is better to step aside (using the wireless remote) before taking the picture, than to spend time cleaning your image in the mirror with Photoshop. If possible, choose an angle so that there are no reflections at all.
- Make sure the lens and sensor are clean. Before you take a picture, make sure that there is no dust on the glass and sensor. Dust can be very troublesome when taking pictures.
- Sharp light from the sun or lighting fixtures can do a lot of damage. Fisheye lenses easily catch glare (bunnies), so find a camera position that minimizes it.
- Watch for moving objects (people, cars). If you are shooting in a crowded place, you will have to wait a while so that no one is in the frame. If this cannot be avoided, shoot when the subject is at the edge of the frame in the overlapping area.
- Tripod stability. Make sure that the tripod stands securely and does not interfere with anyone. If you move the tripod while you are shooting, you will have to completely reshoot the panorama. When the tripod is light, hang something weighty on the hook of the central pole, e.g. a backpack with equipment. This makes it more secure.
- Don’t forget to focus. Adjust the sharpness for each panorama. If you are using hyperfocal, use duct tape to fix the focus ring. This will help you maintain the lens setting as you move from one shooting point to the next.
Basic Panorama Shooting Mistakes
Problems can arise during the creation of 360-degree panoramas. They lead to complications in subsequent processing or even the inability to assemble a spherical panorama. The above mentioned nuances of setting up your equipment and shooting rules will help you to avoid all mistakes. If this is your first experience in creating 3D tours, you are advised to pay special attention to this section.
- If you forget to set the RAW quality for your photos, you can say goodbye to the flexible possibilities for processing your photos.
- The automatic shooting mode will lead to a large variation in the exposure of all photos. Get ready for some painstaking work at the conversion stage.
- A mistake in the exposure setting will result in deep shadows or highlights. Use the exposure adjuster to have the best chance of correcting these flaws.
- A slanted level is a mistake, of course, but it can be corrected. There are tools for leveling the horizon at the stage of panorama gluing.
- Inaccurate adjustment of the panoramic head will lead to poor quality stitching of the circular panorama. In such cases, in the spherical panorama appear “notches” – visible joints of neighboring frames. In some cases, they can be removed in Photoshop.
- Part of a panorama is missing when one or several frames are not completed. You will have to go to the scene again.