Basically, if the shutter-release button is depressed while the Self-timer mode is on, there will be a delay of about 10 seconds before the camera shoot a photo. The period of delayed time is dependent on the camera.

When is self-timer mode used for photo shooting?

Self-timer mode is usually used in the following situations:

1) There is a need to take a photo that includes the photographer. The photographer is completely alone and there is nobody nearby to take a photo for him.

2) There is a need to take a group photo including the photographer. There is nobody nearby to take a photo for the group.

3) When the photographer do not want anyone to take the photo for him even though there is someone nearby to help him.

Did I just shock you? Why do the photographer refuse help from anybody?

This is because not everyone know how to use a camera well. This is especially true when you simply ask anybody nearby to help out.

When someone who does not know much about photography tries to shoot a photo, he may not hold the camera steady enough. He may not wait until the camera is auto focused on the subject before shooting. He may shift the position of the camera before shooting, thus changing the composition of the photo. The end result will be a lousy photo.

Another possible reason is that the person who is trying to help is not really interested to get the job done reasonably well. Though he has agreed to help, he does not really put in efforts to do it well. He will just simply aim and press the button without much consideration. He simply wants to finish the task and gets on with his own things.

When I take a photo of myself, I will need to use a tripod to position the camera properly first. Then, I will aim and adjust the tripod accordingly until I have the picture that I want to capture. Next, I must decide where I am going be as part of the picture. After which, I will switch the camera to self-timer mode and depressed the shutter-release button. Lastly, I will move into the picture and take up the position where I have intended to be. I will wait for the camera to shoot the photo after a 10 seconds delay.

The idea that I will like to share with you is:
Use self-timer mode when there is no one better than yourself to shoot a photo.