Canon 1400 IS: When I take a picture using flash of a close up object, a shadow is cast on the lower right corner of the picture. For pictures that are not taken close up with flash, or taken from further away and just zoomed in to the object, does not have this issue. Do you know what could be causing this shadow issue?

if you're using pop up flash, you'll get more shadows doing a portrait shot than a landscape shot just due to the position of the flash bulb and the angle the shadows are cast.

to avoid harsh shadows moveaway from the bright light,or move object/people close to the backdrop that will reduce the strong shadows.

Was everything set automatic?
Was it a cloudy day?
Did you take pictures in the sun of an object in shadow?
Are your indoor pictures normal?
If you are sure everything was OK, no shadows, no bright objects in the picture, ISO was not set 400, flash was not forced on, etc., call Canon. There are adjustments that calibrate the camera for outdoors. It may need to be recalibrated.

The flash is too close to the lense creating a shadow. You cannot see it, because it is only created by the flash.

I have the same camera and have had the lens cover get stuck and it will leave the dark shadow in the pictures like you describe. It doesn't always happen, but when it does I just gently push the lens cover all the way open with my finger.

TV shows large red spot in middle of tv when dark show are on, you can see it more.  Now blue spots on upper right side too.  Spend way to much on this tv to have these kinds of problems only after 3 yrs.

While in playback mode, image is blinking, the word shadow appears in lower right hand corner, use the info button repeatedly until all disappears and image is pure.

Shadows, especially circular shadows, are pretty common with the pop-up flash. What you are seeing is actually the shadow cast by the end of the lens. This happens especially on wider angle shots.

The solution is to find a way to get the lens out of the way of the flash. You can get an external flash, like a 430ex or 580ex, which elevates the flash far above the lens. That is an expensive option so first you might try making a diffuser for your pop up flash, which softens the source of light and helps eliminate some shadows:

http://www.diyphotography.net/diy-built-in-pop-up-flash-diffuser

http://www.flickr.com/photos/natuurplaat/10362363/

sounds like a shutter leaf dropping into the image. however, they are usually horizontal and more likely to manifest when in landscape mode. (horizontal, normal)
try using flash pointed up to ceiling.
also, could need to check for auto sync speed setting. usually 1/125 to 1/60. if its off, it could be catching the shutter in the wrong place.
check manual for settings for using flash.
mark

The built-in Speedlight on many Nikon cameras is designed to be a convenient way to either light up a dark subject or to add fill light to a daytime scene. The built-in Speedlight cannot replace a full size, external speedlight which should be used when more power or coverage are needed. Because the built-in Speedlight is compact and close to the camera it cannot be used under all conditions. When using a lens that is physically very long, a subject that is very close, or a wide lens hood it is possible that a shadow may be cast upon the subject. Notice, in the sample below, the round shadow in the bottom center of the photo. When the lens is too long or the coverage is too wide with a close subject a shadow of the lens itself is cast. In figure "A" below the lens is casting a shadow. Switching (or zooming) to a shorter lens (figure "B") prevents the shadow and allows even illumination. If your lens, subject, or lens hood choice create a shadow, an external flash (either on the camera's hot-shoe or connected to the camera by a wire or wirelessly) should be used to fully light the subject.