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Digital Zoom

Readers of my reviews will know I'm not a huge fan of digital zoom as it's often a badly implemented and seldom used (by owners) marketing "ploy" to sell cameras which don't have an optical zoom. Digital Zoom is simply cropping (selecting the mid part of the image) and sampling-up, the only advantage in doing digital zoom inside the camera is (a) if you don't have any photo software to magnify (and interpolate) the image or (b) to digitally zoom without zooming the JPEG artifacts.

The C-700UZ is specified, and advertised as having 2.7x digital zoom at full resolution. However in our tests at full digital zoom the reported focal length (in the EXIF header) as 3.2x the maximum optical focal length. Measuring a single vertical element in each image returns the same results, 3.2x larger. I'm not quite sure what's going on here but we're definitely getting 3.2x digital zoom.

Full Optical Zoom, No Digital Zoom, 10x (380 mm equiv.)
Full Optical Zoom, 3.2x Digital Zoom, 32x equiv. (1216 mm equiv.)

The above images were affected slightly by heat haze.


Night Exposures

The C-700UZ allows exposures of up to 16 seconds in Manual Exposure mode, personally I wouldn't use anything over 4 seconds, "hot pixels" are abundant and are far too heavy to be removed in exposures longer than 4 seconds.

F3.6, 1.6 sec
F5.0, 4 sec
F7.0 8 sec
F8.0, 16 sec


Internal Flash

The C-700UZ's internal flash is rated (at ISO 100) as wide: 10 cm - 5.5 m (3.9 in - 18 ft), tele: 1.2 m - 4.4 m (4 ft - 14.4 ft). In our tests it consistently underexposed shots, luckily there is a menu option to adjust the flash output by +/-2 EV in 0.3 EV steps.

I'm not particularly happy with this performance, it's under exposed and does have a very slight yellow cast. Not a bad performance, our wall coverage test, 2 m away, some drop off at the corners but not too bad. Relatively good colour balance, though again under exposed. It's as though the camera isn't using the correct flash power


Low Light Focus

In a new addition to our reviews we'll now be measuring the minimum amount of light under which the camera can still focus. The focus target is our lens distortion test chart (shown here on the right), camera is positioned exactly 2 m (6.6 ft) away. Light levels are gradually dropped until the camera can no longer focus.

This test target is the optimum type of subject for most "contrast detect" AF systems (as it has a vertical line at its center), if the subject were less easy to focus upon then you would need more light.

This is about what we'd expect of a digital camera without an AF assist lamp.

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