Previous page Next page

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 ISO's. 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 (ie. 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). Room temperature is approximately 22°C (~72°F), simulated daylight lighting.

Canon EOS 50D vs. Nikon D300 vs. Pentax K20D vs Sony DSLR-A700

  • Canon EOS 50D: Canon 50 mm F1.4 lens, Aperture Priority, Manual WB,
    Default Parameters (Standard PS), High ISO NR (Default; Standard), JPEG Large / Fine
     
  • Nikon D300: Nikkor 50 mm F1.4 lens, Manual exposure, Manual WB,
    Default Parameters (Normal), High ISO NR (Normal), JPEG Large / Fine
     
  • Pentax K20D: Pentax 50 mm F1.4 lens, Aperture Priority, Manual WB,
    Default Parameters (Bright), High ISO NR off, JPEG Large / Premium

  • Sony DSLR-A700 (Firmware 2.0): Minolta 50 mm F1.4 lens, Manual exposure, Manual WB,
    Default Parameters (Standard), High ISO NR (Normal - default), JPEG Large / Fine
Canon EOS 50D
ISO 100
Nikon D300
ISO 100
Pentax K20D
ISO 100
Sony DSLR-A700
ISO 100
Canon EOS 50D
ISO 200
Nikon D300
ISO 200
Pentax K20D
ISO 200
Sony DSLR-A700
ISO 200
Canon EOS 50D
ISO 400
Nikon D300
ISO 400
Pentax K20D
ISO 400
Sony DSLR-A700
ISO 400
Canon EOS 50D
ISO 800
Nikon D300
ISO 800
Pentax K20D
ISO 800
Sony DSLR-A700
ISO 800
Canon EOS 50D
ISO 1600
Nikon D300
ISO 1600
Pentax K20D
ISO 1600
Sony DSLR-A700
ISO 1600
Canon EOS 50D
ISO 3200
Nikon D300
ISO 3200
Pentax K20D
ISO 3200
Sony DSLR-A700
ISO 3200
Canon EOS 50D
ISO 6400
Nikon D300
ISO 6400
Pentax K20D
ISO 6400
Sony DSLR-A700
ISO 6400
Canon EOS 50D
ISO 12800
n/a n/a n/a

Unsurprisingly at base ISO there is not an awful lot of difference between the contestants (with the exception of the Pentax K20D which by default does not use any noise reduction, resulting in visibly and measurably noisier images at all sensitivities). The 50D produces comparatively clean output that demonstrates a well balanced mixture of chroma and luminance noise reduction. However at ISO 1600 and above it can't quite keep up with the D300 in terms of detail retention. The Canon's more heavy-handed luminance noise reduction inevitably leads to some blurring of fine detail. Output up to ISO 3200 is usable, ISO 6400 should be reserved for emergencies and the inclusion of the ISO 12800 setting was quite frankly pointless.

Gray luminance noise graph

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

Black luminance noise graph

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

Chroma (color) noise graph

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

Previous page Next page
358
I own it
6
I want it
204
I had it
Discuss in the forums

Comments