In anything but full automatic, the shutter opens but won't close unless I press the shudder release button again

Set the camera's release mode to one of the two remote modes. The quick-response remote mode fires the shutter when you press the button on the remote. The delayed remote mode gives you two seconds to hide the remote behind your back before firing the shutter.
To change the release mode, press the [i] button to bring up the information display screen. Press it again to put the cursor in the info display screen. Use the cursor keys to select the release mode --- it's the fifth item from the top along the right edge of the screen --- and press the [OK] button. Use the cursor keys to highlight the desired release mode and press [OK]. To return to shooting mode, press the shutter release button halfway.
Full details are in the "Release Mode" section of the manual (page 35 in my copy). If you need manual, you may download one here.

Hey Julie,

We'll solve your problem in a moment.

Step 1,


First, I need you to look through the viewfinder, and press the shutter release button, half-way, and notice the difference. Don't let go, till you hear a beep sound. The blurriness that you see will clear automatically.

If you hear no noise, and the blurriness doesn't go, try this.


Step 2,

On the lens, there will be a tiny button. It'll have A-M on it. Switch it to 'A', if not already on it.

Once you do that, try step one again. Now, you'll be able to overcome your problem.

Toodles,

Rebel!

=)

The proper order of exposure should be:

Curtain opens/Lense stops down (unless wide open)
Lense shutter closes
When releasing button, curtain closes
When winding, lense shutter opens

If this isn't what's happening, something is wrong. There is only a simple mechanical screw connection between body and lense, so it'd have to be an issue with the gears in the body.

Wow, four days ago.

I would think that the camera has dropped the shutter by now.

There is a mode in the camera that holds the mirror up out of the way for sensor cleaning but this is defaulted as soon as the power is shut off and then turned back on again.

Or the camera was set in manual mode "Bulb" and is waiting for the next command from the photographer to "drop" the shutter "takes a second press of the shutter button.

The lens may be loose (unlocked) and giving a bad command to the camera.

The Canon 40D has a shutter capable of 60,000 actuation so if you are close to this I'd say the shutter has been shot out of it.

Also sometimes the shutter release button sticks and gives the feeling or appearance of a stuck shutter.

Shutter switch also known as a release button have been an issue sometimes where dirt and oil from a person hands get down into the button.

To release shut the camera off, take the battery out, remove and reinstall the lens, shift the taking mode to "P" program or full automatic green box.

With or without the remote control, in the M exposure mode you can select the bulb/time setting. Without the remote, this opens the shutter when you press the shutter release and holds it open while you keep the shutter release pressed. With the remote, this opens the shutter when you press the button on the remote and keeps it open until you press the button again. This allows you to keep the shutter open for up to 10 minutes.

There is a motor/gear assembly inside the camera that moves the lens in and out and covers the lens when it is retracted. When it dropped, you most likely cracked or shifted something out of place. A broken tooth does not stop function, but shudders when it hits the gap. A shifted gear, slips and similarly may cause this effect. If it doesn't open the shudder, you get no picture.

You will need to open it up and attempt to repair the mechanics that drive the lens.

You press the shutter once and that opens the shutter (you do your light painting) then you press the shutter a second time to close the shutter.

When you press the shutter the first time and look in the view finder it will be dark . this is because the mirror has locked its self up while doing the exposure (this is normal) Once you click the shutter a second time the mirror will flop down and you will be able to see threw the viewfinder again.

By "stayed up", do you mean that the mirror remained in the up position so that you could not see anything in the viewfinder or do you mean that the shutter actually remained open? I do not remember the exact features on your camera, but in general, this is what I would do.

1) Remove the film from the camera and take a picture. Note if you see anything in the viewfinder. If you see nothing, the mirror is in the up position. Verify this by removing the lens and opening the door on the camera back. Look through the lens hole. If you can see through the rectangular hole at the film plane, the shutter is open. If instead you something is obstructing the hole, the shutter is closed. In any case DO NOT TOUCH THE SHUTTER! The shutter is what is covering the hole.

2) If the mirror is in the up position, check to see if your camera has a feature that allows locking the mirror in the up position. Some cameras have this feature to allow use of lenses with very short focal lengths. If this is the case, simply unlock the mirror.

3) If the shutter is the problem, your shutter speed may be set to "T", which stands for time. In the time exposure mode, you press the shutter release once to open the shutter and a second time to close the shutter. Cameras with a "T" setting also have a "B" setting, which stands for bulb. This is a throwback to the old days when it was common to use air-powered shutter releases rather then cable releases. The bulb was a rubber bulb that you squeezed to force air through a tube and push a pin to activate the shutter. The "B" setting keeps the shutter open as long as you hold the shutter release in, but as soon as you take your finger off the shutter release, the shutter closes. Both of these settings are used to make timed exposures. If you find that the problem was that the shutter was set to "T", set the shutter speed to 1/25th second or so and try again. The following sequence should occur; the mirror will flip up and the viewfinder image will disappear, the shutter will open for the prescribed time and close, the mirror will return to the down position and you will again see through the viewfinder.

If this does not work, you may need to take it in for repair.

This happened to me to both the Canon's I had. I found out it was a dead battery. Once I replaced those it worked fine. The battery is hidden under the hand grip which can be taken off using a coin in the screw slot.

Sincerely,
Karin

I was having the same problem.. And since I could not afford to take it to the shop, I tried everything I could think of...
Then I fixed it!!
It seems that the slide door behind the shutter was stuck for some reason... If you remove the lens.. (make sure the camera is in manual mode)... snap a shot so the shutter is up.. then gently slide the panel in the back down....
Once I did that.. the camera was working again.... Hope this easy solution works for you guys....