The Coolpix 950 is capable of optical zoom, digital zoom, or a combination of both. Due
to the high resolution of the E950 (and E-700) cameras Digital Zoom does not always result
in a loss in image quality.
Optical zoom is controlled by the two buttons marked "W" and "T"
which lie conveniently under your thumb when you hold the camera. The zoom range is 1:3
and allows the camera's focal length to be varied from the equivalent (on a
35m camera) of 35mm to 115mm.
The zoom control changes the area of the scene that will be included in the picture, so
that the picture appears to be taken from further away with a wide field of view, of from
closer in with a narrower field of view. Throught the optical zoom range, the resolution
of the picture does not change.
The viewfinder lens is linked to the image lens, and gives realistic representation of
the final image.
Digital Zoom is selected manually by pressing and holding the "T"
button for two seconds when the optical zoom is at the Telephoto end of its' range. If the
"T" button is held pressed, the Digital Zoom steps through 1.25, 1.5, 2.0 and
2.5. Pressing and holding the "W" button steps back through the range.
Just like Optical Zoom, Digital zoom also changes the area of the scene that will be in
the picture by selecting a progressively smaller and smaller area of the picture which is
then modified electronically to fill the frame and become an image at the pre-set
resolution.
The camera always uses the full resolution image (1600 x 1200) as the start point from
which to select pixels and then convert them to the pre-set resolution. For example if the
camera is set to 2 x digital zoom, with an image resolution setting of 1600 x 1200,
then the centre 800 x 600 pixels are doubled (interpolated) to become a full size image.
If the final image size is set to be 640 x 480, then the interpolation is used, but in
this case it reduces the number of pixels. If the output image is set to 640 x 480 and 2.5
times digital zoom is chosen, then no interpolation is needed as the selected area is in
fact 640 x 480. (1600/2.5 = 640, 1200/2.5 = 480)
The explanation demonstrates that Digital Zoom does not always result in a loss in
image quality if the output resolution is the same or smaller than the actual number of
pixels selected to form the image.
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