Most of the cameras have along the base settings a feature able to give you a hand in creating panoramic images. Usually this setting has several functions. First of them is the one showing you the picture you just took and only then moving to the visualization of what you plan to shoot.
This helps you align the pictures so you know how to overlay them. Setting the camera for only one exposure so that it does not change between the pictures you take is a good idea. This helps you create a special kind of luminosity inside your pictures which will allow you to post-process them easily in case you don’t want to use a specific post-processing software feature.
The overlay is one of the most important aspects of panoramic photos. A single overlay mistake can destroy the whole photo taken from a wide angle.
Nobody wants a picture of the Grand Canyon with a white line in the middle caused by the absence of a correct overlay. The correct overlay for this type of picture is 30% but most of the professional photographers use the average 15%.
Keeping the same level in all the shots becomes extremely important as you combine several images. You must not stress on this if you have only 4 or 5 photos to work with. However, if the number of photos increases to 40, keeping the level constant is a very important factor. Consider that the camera lens, no matter how performing, is made of curved glass and if you keep the level constant you will obtain exactly the same angle.
If you direct the camera 45 degrees lower, in the photo will appear distant objects like the mountains from the background which will be captured from a narrower angle than the main subject of the photo.
When taking only one shot it will not be a problem. But in the case of a panoramic picture this will create an effect impossible to repair. This happens because as you capture the scene from left to right you no longer have a wide exposure. Even more you may get distortional curved images created by the angle the light used to enter the digital camera.