Overall Image Quality
I'll cover the good first, for its price point the C-700UZ produces fairly sharp, high resolution (for a 2 megapixel) and well colour balanced images. The big zoom will get you into places you wouldn't otherwise be able to reach and assuming you have fairly good light you'll get away without the need for image stabilization. Indeed, as long as your shot doesn't have any bright highlights / backlight / strong contrast areas you'll probably never see the problems we discuss below.
Sadly the C-700UZ is dogged by chromatic aberration and moiré pattern problems. These became most obviously apparent when we went out for our first real photo shoot test session which happened to be one of the nicest, sunniest British days for a long time. It's fair at this point to say that most digital cameras suffer from chromatic aberrations to one degree or another, and that most long zoom even more so, but the C-700UZ's were towards the extreme.
Purple Fringing (Chromatic Aberrations)
As you can see chromatic aberrations were clearly visible not just on high contrast areas but anywhere in the image which was a "highlight" (over or almost over saturated), the fringe itself appears to be a combination of chromatic aberrations, moiré and blooming.
Chromatic aberrations is a term we use (accurately enough) but it's more accurately to do with the interaction of the camera's lens and the microlens structure which is on top of the CCD surface.
Both of the shots below look ok at first glance, and indeed may look fine reduced to VGA (640 x 480) or XGA (1024 x 768) but the telltale yellow / blue discoloration on fine detail are a sure sign of moiré. This was confirmed after we shot the resolution chart for the camera, strong moiré is visible between 900 and 1350 lines per picture height.
Moiré is defined as frequency aliasing which is caused by frequencies above the CCD's Nyquist frequency (the highest spatial frequency where the CCD can still faithfully record image detail).
Barrel and Pincushion Distortion
As we'd expect from such a compact long zoom lens the C-700UZ does suffer from notable barrel distortion at the wide end, surprisingly (and I've not seen this before) we also measured (nominal) barrel distortion at full tele. Very odd.
|Barrel Distortion, 1.3% @ Wide Angle||Barrel Distortion, 0.4% @ Full Tele|
Overall the camera's Auto white balance seemed to work well, even under artificial lighting. The one-touch manual mode also seemed to work well, there's a slight hue shift (and dullness to reds) under fluorescent light. On the whole a good performance.
|Outdoors, Auto||Outdoors, Cloudy||Outdoors, Manual|
|Incandescent, Auto||Incandescent, Indoor||Incandescent, Manual|
|Fluorescent, Auto||Fluorescent, Fluorescent||Fluorescent, Manual|
Olympus Camedia C-720 3MP Digital Camera
w/ 8x Optical Zoom