For those of you owning Canon A400 series (A400 through A490), please see this link after trying the below troubleshooting steps, as you may also be experiencing a broken shutter ribbon cable.
A stuck shutter is a common failure mode for digital cameras. Unfortunately some model cameras experience this more than others. I won't say which but you'll likely notice in the comments section which cameras these are. The symptoms of a stuck or "sticky" shutter are very similar to CCD image sensor failure. The camera may take black pictures (for shutter stuck closed), or the pictures may be very bright and overexposed, especially when taken outdoors (for shutter stuck open). To confirm a stuck shutter, put the camera in any mode other than "Auto", and turn the flash OFF (you don't want to blind yourself for the next step). Next look down the lens and take a picture. You should see a tiny flicker in the center of the lens as the shutter opens and closes. If no movement is seen, then you likely have a stuck shutter.
If you did see movement, then you are possibly experiencing CCD image sensor failure. As mentioned, the symptoms of a stuck shutter are very similar to CCD failure. If you own a Canon or Sony camera, please see the following two articles instead as your camera might possibly be eligible for free repair:
Canon CCD advisory article
Sony CCD advisory article
Unfortunately, actual mechanical repair of a stuck shutter is labor intensive as the mechanism is buried deep inside your camera. If the camera is out of warranty the cost of this repair is usually very high, and may be more than the value of the camera. Would not recommend trying to open your cameras to repair this yourself, as it's very unlikely that you'll succeed. However, there is something simple that you can try that might unstick it, albeit it may be only a temporary fix. Also would not recommend that you do this on a perfectly working camera, as I'm not sure what the power interuptions may do to the camera. As usual, only think of doing this procedure as a last resort for a camera that repair cost is out of the question, and as such the camera would otherwise be set for disposal:
Step 1. Turn the camera on. Also turn off any features that may be a power drain to the batteries. You want all available power from the batteries for the following steps. Turn off image stabilization if your camera has that feature. Put the camera in any mode other than Auto, and turn off the flash. Also turn off the LCD screen (press the DISP or DISPLAY button).
Step 2. Move the camera to any mode that will give you the longest exposure time without flash. For many Canon cameras this will be shutter priority (Tv) mode (for many Canon A models the wheel with AUTO,M,Tv,...). For some of the Canon SD models this is also known as "Long Shutter Mode" (select the Moon/Stars icon).
If you did see movement, then you are possibly experiencing CCD image sensor failure. As mentioned, the symptoms of a stuck shutter are very similar to CCD failure. If you own a Canon or Sony camera, please see the following two articles instead as your camera might possibly be eligible for free repair:Canon CCD advisory article
Sony CCD advisory article
Unfortunately, actual mechanical repair of a stuck shutter is labor intensive as the mechanism is buried deep inside your camera. If the camera is out of warranty the cost of this repair is usually very high, and may be more than the value of the camera. Would not recommend trying to open your cameras to repair this yourself, as it's very unlikely that you'll succeed. However, there is something simple that you can try that might unstick it, albeit it may be only a temporary fix. Also would not recommend that you do this on a perfectly working camera, as I'm not sure what the power interuptions may do to the camera. As usual, only think of doing this procedure as a last resort for a camera that repair cost is out of the question, and as such the camera would otherwise be set for disposal:
Step 1. Turn the camera on. Also turn off any features that may be a power drain to the batteries. You want all available power from the batteries for the following steps. Turn off image stabilization if your camera has that feature. Put the camera in any mode other than Auto, and turn off the flash. Also turn off the LCD screen (press the DISP or DISPLAY button).
Step 2. Move the camera to any mode that will give you the longest exposure time without flash. For many Canon cameras this will be shutter priority (Tv) mode (for many Canon A models the wheel with AUTO,M,Tv,...). For some of the Canon SD models this is also known as "Long Shutter Mode" (select the Moon/Stars icon).
For cameras other than Canon, set the camera so that it will take the longest possible exposure, usually 15 seconds (15"). Many cameras may not have shutter priority mode (Tv). Instead, put the camera in manual mode and turn off the flash. With these settings, try the fix in a darkened room, opening the battery door immediately after taking the picture. The darkened room without flash should give you a prolonged exposure, hopefully giving you enough time to conduct Step 4 while the shutter is trying to move.
Step 3. Take a picture.
Step 4. After 7 seconds open the battery door for a few seconds and then close it again. The intent is to momentarily interupt power during the exposure time. Note that you may also open the battery door immediately after pressing the shutter button if your camera is not capable of taking 15 second exposures.
Step 5. Repeat the procedure until the shutter becomes unstuck. One person reported on Fixya doing this 15 times before his shutter became unstuck.
Step 3. Take a picture.
Step 4. After 7 seconds open the battery door for a few seconds and then close it again. The intent is to momentarily interupt power during the exposure time. Note that you may also open the battery door immediately after pressing the shutter button if your camera is not capable of taking 15 second exposures.
Step 5. Repeat the procedure until the shutter becomes unstuck. One person reported on Fixya doing this 15 times before his shutter became unstuck.
Supposedly the power interuption while the shutter is trying to open can "jog" the shutter open. Some people have reported success with this method, and they noted that it required many tries.
Step 5a. Alternative Fix (use caution!). Please use common sense and care if you decide to try this technique, as there is some obvious potential for further damaging your camera with this step. If the above five steps don't work after many repeated tries, several readers have reported success in jogging the shutter open by tapping the camera against a wooden surface.
Step 5b. Alternative Fix b. If 5a scares you, others have reported success with an alternate method of merely extending the lens and then gently tapping around the extended lens barrel with a pen or pencil. Every once in a while check down the barrel to see if you notice lens flicker when taking a picture. If none noted, continue tapping. I have personally repaired two different Canon SD1000's by merely gently flicking the end of the lens barrel with the tip of my index finger while taking a picture.
Gently Tapping Around the Extended Lens Barrel
Anonymous reader of July 25th offers two more Steps:
Step 6a: In a very dark room to open the camera's iris, switch back and forth on the selector dial from picture taking mode to playback mode. Keep switching back and forth between modes until the shutter opens. Gently tap on the lens housing with a pencil or pen while conducting these cycles.
Step 6b: Again, in a very dark room, place the camera in shooting mode and then open and close the battery cover. No need to place the camera in Tv mode or set to 15 second exposure. Any shooting mode will do while you open and close the battery door. Keep repeating until the shutter opens. Gently tap on the lens housing with a pencil or pen in between tries.
IMPORTANT, Post-Repair Step: If you succeed in fixing your camera, note that this may also be only a temporary fix, and you may be required to do it again. To minimize this potential, place the camera in "Continuous Shutter" mode, and take a large amount of pictures continuously to attempt to lubricate the shutter (you can delete those pictures later). Also, try to use your camera more often as another preventative measure from reoccurrence.
Note that cameras with shutters that are stuck open (overexposed pics) can be particularly difficult to repair with the above techniques. But I do know that Step 5b can work for both stuck open and stuck closed shutters (of those SD1000's that I've repaired, one was stuck open). Hopefully you'll be lucky too. But if not, it may be time to consider retiring the camera.
Finally, please comment below whether you succeeded or not with this technique along with your camera model. Also note how many tries you gave it. If you know of another method, please also report that here.