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ISO Sensitivity / Noise levels

ISO equivalence on a digital camera is the ability to increase the sensitivity of the sensor. This works by turning up the "volume" (gain) on the sensor's signal amplifiers (remember the sensor is an analogue device). By amplifying the signal you also amplify the noise which becomes more visible at higher ISOs. Many modern cameras also employ noise reduction and / or sharpness reduction at higher sensitivities.

To measure noise levels we take a sequence of images of a GretagMacBeth ColorChecker chart (controlled artificial daylight lighting). The exposure is matched to the ISO (i.e. ISO 200, 1/200 sec for consistency of exposure between cameras). The image sequence is run through our own proprietary noise measurement tool (version 1.5 in this review). Click here for more information. (Note that noise values indicated on the graphs here can not be compared to those in other reviews.)

First we have compared the camera in its full resolution (HR) mode to its performance in 6MP sensitivity priority (SN) mode. Then, to show what difference the pixel binning mode makes, we've downsized the 12MP output to 6MP (using Photoshop's Bicubic Sharper setting).

HR mode vs. SN mode vs. Downsized HR mode.

HR (12MP) mode
ISO 100
SN (6MP) mode
ISO 100
HR downsized to 6MP
ISO 100
HR (12MP) mode
ISO 200
SN (6MP) mode
ISO 200
HR downsized to 6MP
ISO 200
HR (12MP) mode
ISO 400
SN (6MP) mode
ISO 400
HR downsized to 6MP
ISO 400
HR (12MP) mode
ISO 800
SN (6MP) mode
ISO 800
HR downsized to 6MP
ISO 800
HR (12MP) mode
ISO 1600
SN (6MP) mode
ISO 1600
HR downsized to 6MP
ISO 1600

The differences between the full resolution 'HR' mode and the pixel-binned 6MP 'SN' mode are subtle, to say the least. By ISO 1600 it's obvious that the SN mode, which combines the data from similarly colored photosites, it does a better job of reining-in chroma noise but there's not a lot to choose between the two in terms of detail or, until the higher settings, luminance noise. (The downsized HR images look slightly sharper because the downsizing technique used applies additional sharpening to counteract the inherent softening effects of downsizing). In terms of measured values, the SN mode does offer a benefit over the HR mode but visually, it's too close to call.

Fujifilm FinePix F200 EXR vs. Panasonic Lumix DMC-LX3 vs. Canon Powershot SD 960IS

Fujifilm FinePix F200 EXR
n/a
Panasonic LX3
ISO 80
Canon SD 960 IS
ISO 80
Fujifilm FinePix F200 EXR
ISO 100
Panasonic LX3
ISO 100
Canon SD 960 IS
ISO 100
Fujifilm FinePix F200 EXR
ISO 200
Panasonic LX3
ISO 200
Canon SD 960 IS
ISO 200
Fujifilm FinePix F200 EXR
ISO 400
Panasonic LX3
ISO 400
Canon SD 960 IS
ISO 400
Fujifilm FinePix F200 EXR
ISO 800
Panasonic LX3
ISO 800
Canon SD 960 IS
ISO 800
Fujifilm FinePix F200 EXR
ISO 1600
Panasonic LX3
ISO 1600
Canon SD 960 IS
ISO 1600
Fujifilm FinePix F200 EXR
ISO 3200
Panasonic LX3
ISO 3200
Canon SD 960 IS
n/a*
Fujifilm FinePix F200 EXR
ISO 6400
Panasonic LX3
n/a
Canon SD 960 IS
n/a
Fujifilm FinePix F200 EXR
ISO 12800
Panasonic LX3
n/a
Canon SD 960 IS
n/a

*The Canon SD 960 IS (IXUS 110 IS) does have an ISO 3200 mode but you cannot apply exposure compensation or custom white balance, so it can't be used to achieve a result that would be meaningful in this test.

Having seen that the full-resolution HR images are not significantly different in terms of either noise or detail, here we use them to compare to two other, more conventional cameras: the Panasonic LX3 and the Canon SD 960 IS. The Panasonic has a sensor of a similar size to the Fujifilm, while the Canon uses a sensor with a surface area around 40% smaller. Even from as low as ISO 200, that size advantage is very apparent with the Fujifilm and Panasonic trouncing the Canon's muddied output.

The Panasonic however is able to retain detail better than the Fujifilm and with similar or lower levels of noise. The inescapable conclusion of these tests is that the F200's pixel-binned output is not significantly better than one of its full-resolution images downsized and that this output isn't quite as good as the very best out there. It's a distinct improvement on most, though.

Luminance noise graph

Cameras compared:
Fujifilm FinePix F200 EXR, Panasonic LX3, Canon SD 960 IS

F200 EXR in 12MP mode F200 EXR in 6MP EXR SN mode

Indicated ISO sensitivity is on the horizontal axis of this graph, standard deviation of luminosity is on the vertical axis.

The Canon appears to produce the lowest noise from ISO 400 upwards but as we've seen from the crops further up this page, this is mainly due to the high levels of noise reduction being applied. The F200 EXR produces less luminance noise (both in the blacks and at middle gray) than the LX3 all the way up to ISO 800 in HR mode. In SN mode it is at least as good as the LX3 all the way up to 1600.

RGB noise graph

F200 EXR in 12MP mode F200 EXR in 6MP EXR SN mode

Indicated ISO sensitivity is on the horizontal axis of this graph, standard deviation of each of the red, green and blue channels is on the vertical axis.

It's a similar story for Chroma noise, with the Canon's image-degrading noise reduction seemingly giving it an edge at ISO 1600. In image quality terms though, the crops show that it's a straight fight between the F200 and the LX3. Both cameras are pretty evenly matched, regardless of whether the F200's HR or SN mode is used.

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