Many if not most digital SLR cameras have it. The self-timer mode can be used to reduce camera shake or for taking self-portraits. In practice, I found this feature not as useful as it should be, at least on my Nikon D200.
To reduce camera shake, and the blur it causes, I prefer a remote shutter release because it is more efficient: no need to waste the extra seconds between shots.
For self-portraits, I found it almost useless. Why? Because the moment after I press the shutter release after framing the photograph, it immediately tries to focus. It will either focus on the wrong things, or fail to focus at all due to lack of contrasty details in the background.
How about using manual focus? Not a good solution because there is nothing to focus on. Remember, the photographer is still trying to get the shot setup behind the camera!
How about using a very small aperture to obtain a large enough depth-of-field (DOF)? Not good either. The shutter speed may become too slow to freeze motion, or it reduces the light intensity significantly (practically to nil) if you use a flash.
To be fair, the self-timer mode does work well on group portraits that need to include the photographer. You can focus on other people in the group first.
I wish there was an option (custom setting) to delay the start of autofocus by a few seconds after the shutter release is pressed down to allow the subject to get to the spot and be ready. It should be quite easy to do with simple software/firmware change.
Before that becomes a reality, I have found a couple of solutions to this self-timer mode issue with my Nikon D200.
Solution #1: Use the Interval Timer function. I set it up to take at least two shots with a few seconds in between. The first shot may be bad but the camera will try to re-focus on the second shot.
Solution #2: Use a remote shutter release instead. I have the MC-30, but the cord is too short. So I found a wireless shutter release on eBay for a little over half the price of the MC-30. The remote is so small that it can be easily hidden in the palm (with the antenna pushed in). It even has a built-in timer function so you can hit the button and get yourself ready.
Here is the picture of the wireless remote for Nikon DSLRs with 10-pin connector. The receiver unit can also be used as a wired shutter release. The coin is a US quarter.
Keywords: Self Portrait, Self Timer Mode, Self-Timer