If HDMI cables are used, the picture is a pixel-by-pixel representation of the incoming signal, and may not be able to be adjusted. Component cables, on the other hand, may offer more options, since it's an analog signal that can take advantage of those options.
Samsung PN50C7000 50-Inch 1080p 3D Plasma HDTV (Black)
Latest firmware as of 12/19/2010
Zoom 1 and Zoom 2 are disabled when the TV is in 720 or 1080 resolutions. This is a mistake as there are cases where the Zoom 1 and Zoom 2 modes are needed even when viewing content broadcast in HD resolutions. Please re-enable them.
The TV has the following "size" modes:
When the TV is viewing 720 or 1080 content, the Zoom 1 and Zoom 2 modes are not available. However I have frequently seen HD content that requires them. The most common case is when a channel is broadcast in HD resolutions but is showing a program that has a 16:9 picture within permanent letterbox black bars. That is, the letterbox black bars were not added by the TV, but were added on the stations end or are on the original material they are broadcasting.
With such a show, if the TV is in 4:3 mode, then the picture is the right shape, but it has both letterbox and pillbox black bars (black bars on all sides). If I set it to 16:9 mode, then the left and right edges of the picture are stretched to the edges of the TV, but it still has the black bars on the top and bottom, so the shows picture is vertically squeezed, making people look short. All the other available modes distort the picture as well (remember, Zoom 1 and 2 are disabled with HD content).
Now, if a non-HD channel has a 16:9 show with letterbox black bars, then the 16:9 mode does the exact same thing as before. But because the channel is broadcasting in standard definition, the TV's resolution is set to 480, enabling Zoom 1 and Zoom 1. If I set it to Zoom 1, then the picture gets vertically stretched just enough to restore the shows 16:9 aspect while having it fill the entire screen.
Bottom line, there are cases where the Zoom 1 and Zoom 2 modes are needed even when viewing content broadcast in HD resolutions. Please re-enable them.