Covering a wide angle view is done by taking a panoramic digital photo. A panoramic digital photo can capture wide angle photos all the way to 360 degrees. One example is taking a panoramic 360 degree view from a high rise building to capture the view. The Canon PowerShot SD870 IS like many other cameras support a special panoramic mode that helps taking panoramic photos.
Panoramic photos are as the name suggest a series of photos taken that when attached to each other provide a panoramic view of the scene. The Canon PowerShot SD870 IS when put in panoramic mode helps the photographer to take that series of photos also known as segments in a way that makes attaching them together later on easy and fast. Attaching the segments together is a process also known as digital photo stitching. It can be done either manually or automatically. When done automatically special software on your computer identifies overlapping areas in the segments and tries its best to attach them to achieve a perfect panoramic digital photo.
The Canon PowerShot SD870 IS makes stitching the digital photo segments easier. This is done in two ways. First the segments are name coded in a way that the stitching software can tell which segment is first which is second and so on. The only thing left to do is to let the software know if the segments were taken vertically or horizontally and if they were taken from left to right or top to bottom or vice versa. Once the stitching has that information the only thing left is to perfectly attach each pair of photos. This is done by identifying overlapping areas and try to perfectly find the position in which the two segments are attached into one photo.
This last stage is made easier by the Canon PowerShot SD870 IS guaranteeing that there is enough overlapping area between segments. This is done by letting the photographer see the previous segment when taking each consecutive segment. The photographer can then make sure that there is enough overlapping area between them.
With all the technology in the Canon PowerShot SD870 IS and the stitching software there are still some basic rules that the photographer should follow when taking panoramic photos. Try to stay at a steady position when taking the panoramic segments. It is best if the camera stays in one fixed position and usually it is easier to achieve that by using a tripod. It is also good practice to keep the optical digital camera setting fixed such as aperture and shutter speed. If one segment is dramatically optically different then another segment the stitching software might have hard time attaching the two and the result panoramic photo might also look bad as parts of it look different.
The same is true for zoom and focus setting. Do not change the zoom settings or the focus when taking the segments. This can be a challenge for example when taking a 360 degrees panoramic digital photo. You can find yourself in situation where one segment is taking against the sun light and one with the sun behind the camera. In such cases you might be forced to change the optical setting to compensate for those lighting changes to achieve steady segments.