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 S2 Pro provides a good range of selectable sensitivities between ISO 100 and 1600 in 1 stop steps (apart from ISO 160).

Our noise comparison test involves shooting a colour patch chart (a GretagMacBeth ColorChecker) at the full range of ISO sensitivities and then measuring noise at three patch positions.

Each of the comparison crops below are made up of a 180 x 80 crop of patches 19, 22 and 24 of the ColorChcker chart (as indicated above). This helps to give a better impression of noise at different light levels within an image. Directly below this you will find the average standard deviation of these three patches, this is a quantifiable measurement of noise.

Test Notes

• We are now using the GretagMacBeth ColorChecker instead of Kodak Colour patches for a couple of reasons: (a) The grey patches are larger and are therefore easier to crop / measure (b) The patches are made from a matte non-reflective material and are therefore easier to shoot without accidental reflection.
• Both cameras were configured as close to normal 'every day' use as possible, this means Standard sharpening on the S2 Pro and Normal sharpening on the D100.
• Measurements were taken at approximately 23°C (~73°F), you should expect more noise at higher temperatures and less at lower temperatures.
• Nikon RAW images converted to 8-bit TIFF using Nikon Capture 3.0, default settings (camera settings carried through).
• Fujifilm RAW images converted to 8-bit TIFF using RAW File Converter EX, camera settings.
• Fujifilm FinePix S2 Pro: Standard Sharpening, Standard Tone, Standard Colour, Manual WB
• Nikon D100: Normal Sharpening, Auto Tone, Colour Mode I (sRGB), Manual WB
• Lighting: Daylight
• The 'standard deviation' was measured using the histogram feature in Photoshop on 8-bit TIFF or JPEG files (later comparison). Lower figures mean there is less 'deviation' from the average luminance level, and thus less noise.

Fujifilm FinePix S2 Pro (12 mp JPEG) vs. Nikon D100 (JPEG)

Camera	Fujifilm FinePix S2 Pro	Nikon D100
Sensitivity	ISO 100	n/a
Exposure	1/15 sec, F8.0	n/a
Patch crops  ISO 100  JPEG
Standard dev. avg.	0.91	-
Camera	Fujifilm FinePix S2 Pro	Nikon D100
Sensitivity	ISO 200	ISO 200
Exposure	1/30 sec, F8.0	1/30 sec, F8.0
Patch crops  ISO 200  JPEG
Standard dev. avg.	1.11	1.25
Camera	Fujifilm FinePix S2 Pro	Nikon D100
Sensitivity	ISO 400	ISO 400
Exposure	1/60 sec, F8.0	1/60 sec, F8.0
Patch crops  ISO 400  JPEG
Standard dev. avg.	1.23	1.56
Camera	Fujifilm FinePix S2 Pro	Nikon D100
Sensitivity	ISO 800	ISO 800
Exposure	1/125 sec, F8.0	1/125 sec, F8.0
Patch crops  ISO 800  JPEG
Standard dev. avg.	1.42	2.03
Camera	Fujifilm FinePix S2 Pro	Nikon D100
Sensitivity	ISO 1600	ISO 1600
Exposure	1/250 sec, F8.0	1/250 sec, F8.0
Patch crops  ISO 1600  JPEG
Standard dev. avg.	2.03	2.91

When Fujifilm first announced the S2 Pro they also made note that the SuperCCD III sensor and processing system built into the camera has a progressive noise reduction system which varies its strength depending on the selected sensitivity. As we can see from the results above (and the graph below) this automatic noise reduction system does appear to work well. Noise levels are consistently lower than the D100 and from ISO 400 upwards the S2 Pro is cleaner than the Canon EOS-D60. Note that we tested the S2 Pro at both 12 mp and 6 mp, the 6 mp results are reflected in the graph below.

Fujifilm FinePix S2 Pro (12 mp RAW) vs. Nikon D100 (RAW)

Camera	Fujifilm FinePix S2 Pro	Nikon D100
Sensitivity	ISO 100	n/a
Exposure	1/15 sec, F8.0	n/a
Patch crops  ISO 100  RAW
Standard dev. avg.	1.00	-
Camera	Fujifilm FinePix S2 Pro	Nikon D100
Sensitivity	ISO 200	ISO 200
Exposure	1/30 sec, F8.0	1/30 sec, F8.0
Patch crops  ISO 200  RAW
Standard dev. avg.	1.28	1.53
Camera	Fujifilm FinePix S2 Pro	Nikon D100
Sensitivity	ISO 400	ISO 400
Exposure	1/60 sec, F8.0	1/60 sec, F8.0
Patch crops  ISO 400  RAW
Standard dev. avg.	1.68	2.13
Camera	Fujifilm FinePix S2 Pro	Nikon D100
Sensitivity	ISO 800	ISO 800
Exposure	1/125 sec, F8.0	1/125 sec, F8.0
Patch crops  ISO 800  RAW
Standard dev. avg.	1.67	2.82
Camera	Fujifilm FinePix S2 Pro	Nikon D100
Sensitivity	ISO 1600	ISO 1600
Exposure	1/250 sec, F8.0	1/250 sec, F8.0
Patch crops  ISO 1600  RAW
Standard dev. avg.	2.66	4.77

Again the progressive noise reduction system (which must also be included in the RAW conversion software) produces good results even at high sensitivities. Note that noise levels are slightly higher for S2 Pro RAW files converted to TIFF.