ISO Sensitivity / Noise levels

Standard Test

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" (gain) on the CCD's signal amplifiers. Nothing is without its price however and doing so also typically increases visible noise (random speckles visible all over the image).

We are now using a more reliable, repeatable and neutral method for evaluating noise. Shots are taken in daylight lighting in our studio. Noise is measured as the standard deviation of the medium gray patch on a Gretag MacBeth ColorChecker chart. The image is normalized before measurement of noise to remove the possibility of figures being affected by image contrast (one method of masking noise). Note that noise numbers shown on the graphs below can not be compared to those in older reviews.

Test notes:

• Shots taken at approximately 21°C (~70°F)
• Lighting was simulated daylight
• Manual white balance
• Aperture Priority

Nikon D70 vs. Canon EOS 300D

• Nikon D70: Nikkor 50 mm F1.4 lens, Aperture Priority (F3.5), Manual WB,
  Default Parameters, JPEG Large / Fine
   
• Canon EOS 300D: Canon 50 mm F1.4 lens, Aperture Priority (F4.0), Manual WB,
  Default Parameters (Standard), JPEG Large / Fine

	Nikon D70 n/a	Canon EOS 300D ISO 100, 1/100 sec, F4.0
Partial crop
Red Green Blue channels
	Nikon D70 ISO 200, 1/200 sec, F3.5	Canon EOS 300D ISO 200, 1/200 sec, F4.0
Partial crop
Red Green Blue channels
	Nikon D70 ISO 400, 1/400 sec, F3.5	Canon EOS 300D ISO 400, 1/400 sec, F4.0
Partial crop
Red Green Blue channels
	Nikon D70 ISO 800, 1/800 sec, F3.5	Canon EOS 300D ISO 800, 1/800 sec, F4.0
Partial crop
Red Green Blue channels
	Nikon D70 ISO 1600, 1/1600 sec, F3.5	Canon EOS 300D ISO 1600, 1/1600 sec, F4.0
Partial crop
Red Green Blue channels

Visually a very similar performance, although looking at the split out RGB crops you can see that the pattern of noise is quite different at higher ISO's. At ISO 1600 the 300D's noise pattern is quite large and blotchy, the D70 with much finer more granular noise.

Nikon D70 vs. Nikon D100

• Nikon D70: Nikkor 50 mm F1.4 lens, Aperture Priority (F3.5), Manual WB,
  Default Parameters, JPEG Large / Fine
   
• Nikon D100: Nikkor 50 mm F1.4 lens, Aperture Priority (F3.5), Manual WB,
  Default Parameters, JPEG Large / Fine

	Nikon D70 ISO 200, 1/200 sec, F3.5	Nikon D100 ISO 200, 1/200 sec, F3.5
Partial crop
Red Green Blue channels
	Nikon D70 ISO 400, 1/400 sec, F3.5	Nikon D100 ISO 400, 1/400 sec, F3.5
Partial crop
Red Green Blue channels
	Nikon D70 ISO 800, 1/800 sec, F3.5	Nikon D100 ISO 800, 1/800 sec, F3.5
Partial crop
Red Green Blue channels
	Nikon D70 ISO 1600, 1/1600 sec, F3.5	Nikon D100 ISO 1600, 1/1600 sec, F3.5
Partial crop
Red Green Blue channels
	Nikon D70 n/a	Nikon D100 ISO 3200, 1/3200 sec, F3.5
Partial crop
Red Green Blue channels

Unsurprisingly the D70 and D100 appear to be neck and neck, the D70 makes a better job of the manual preset white balance and maintaining color neutrality at higher sensitivities, the D100's higher ISO gray patch taking a slightly pink cast.

Luminance noise graph

Indicated ISO sensitivity is on the horizontal axis of this graph, standard deviation of luminosity (normalized) on the vertical axis. Note that we have standardized on a 0-10 scale.

RGB noise graph

Indicated ISO sensitivity is on the horizontal axis of this graph, standard deviation of each of the red, green and blue channels (normalized) are on the vertical axis. Note that we have standardized on a 0-10 scale.