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ISO Sensitivity / Noise levels

ISO equivalence on a digital camera is the ability to increase the sensitivity of the sensor to enable faster shutter speeds and/or better performance in low light. The way this works in a digital camera is by "turning up the volume" on the CCD's signal amplifiers, nothing is without its price however and doing so also amplifies any noise that may be present and often affects colour saturation.

The 6900Z featured ISO sensitivities of 100, 200 and 400. This year the S602Z sports ISO 160, 200, 400, 800 and 1600. There is a catch though, ISO 800 and 1600 are only available at 1 MP (1280 x 960) resolution. This (combined with the SuperCCD processing) makes it difficult to find a digital camera similar enough to produce accurate comparisons.

Noise levels

In the absence of a direct comparison you will find below I have simply provided a montage of 60 x 60 pixel crops from our standard GretagMacBeth ColorChecker shot taken at each selectable sensitivity. Remember that at ISO 800 and 1600 the camera is actually combining adjacent pixels to produce more "effective" sensitivity.

ISO 160
(6 MP)
ISO 200
(6 MP)
ISO 400
(6 MP)
ISO 800
(1 MP)
ISO 1600
(1 MP)

As we can see the S602Z does manage to keep noise levels fairly low all the way up to ISO 400, beyond this more noise is definitely visible and you're also limited to shooting at 1280 x 960. Overall a good performance.

94% of the frame at ISO 800, 1600 ?

One thing I did note was that when you switch into ISO 800 and 1600 you lose approximately 6% of the frame. Keeping the camera on a tripod and not altering zoom but simply increasing the sensitivity from ISO 400 to 800 the ISO 800 shot seems to crop the center 94% of the frame (as indicated by the red box in the diagram below). What's even more curious is that the LCD monitor view and 'post view' after taking the shot show the entire frame, but if you switch to play mode you will see the cropping effect. This is worth noting.

White Balance

The S602Z has a very wide range of white balance settings, no less than six pre-programmed settings (including three temperatures for fluorescent bulbs), fully automatic and two manual presets (although the S602Z has lost the 6900Z's useful manual white balance one-touch button). As we've come to expect the S602Z's automatic white balance appeared to work best outdoors (natural light), although it did make a fairly good attempt at guessing the colour temperature of our incandescent and fluorescent lamps.

As you will also be able to see by looking down the right hand column switching to manual white balance mode and taking a measurement is still by far the most accurate and consistent method.

Outdoors, Auto Outdoors, Cloudy (or Sunny) Outdoors, Manual
Incandescent, Auto Incandescent, Incandescent Incandescent, Manual
Fluorescent, Auto Fluorescent, FL3 (also FL1, FL2) Fluorescent, Manual

First word indicates the light in which the shot was taken, the second indicates the selected white balance mode.

Macro Focus

The S602Z has two macro modes, first is the normal macro mode we saw on the 6900Z. Press the macro button and zoom range is limited to about half zoom (3x) this is the point at which you get the best frame coverage (magnification) and closest subject distance. The second macro mode called "Super Macro" (press macro button again) locks the zoom at full wide-angle. In "Super Macro" mode you can get as close as 1 cm to the subject, however this leads to two problems (1) very noticeable barrel distortion and (2) lighting issues, it's difficult to light the subject when the lens is so close (especially considering the diameter of the S602Z's lens barrel).

Normal macro mode, best frame coverage approximately 55 mm
"Super macro" mode, best frame coverage approximately 37 mm

Low Light Focus

This test measures 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 is carried out at both wide angle and telephoto zoom positions (as more light reaches the focusing systems with a larger aperture).

This test target is the optimum type of subject for most "contrast detect" AF systems (as it has a vertical line at its center), you should consider the results below the best you could expect to achieve.

Lens position Aperture Lowest light focus
Wide angle (35 mm) F2.8 3.0 EV (20.0 Lux / 1.9 foot-candle)
Telephoto (210 mm) F3.1 3.0 EV (20.0 Lux / 1.9 foot-candle)

Light intensity (Lux) = 2.5 x 2^EV (@ ISO 100), 10.76391 Lux = 1 foot-candle (fc)

Despite the S602Z's "twin AF" system (passive external sensor combined with TTL CCD AF) it still required quite a bit of light to focus (compared to other 'prosumer' digital cameras). It's a shame that Fujifilm couldn't slip an AF assist lamp into the design of this new camera.

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