Pentax K200D Review: 15. Photographic tests (Noise): Digital Photography Review

ISO Sensitivity / Noise levels

ISO equivalence on a digital camera is the ability to increase the sensitivity of the sensor. The 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 1.4 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.

Pentax K200D vs. Canon EOS 450D (Rebel XSi) vs. Olympus E-520 vs Nikon D60

Pentax K200D: Pentax 50 mm F1.4 lens, Aperture Priority, Manual WB,
Default Parameters (Bright Tone), JPEG Large / Best
Canon EOS 450D: Canon 50 mm F1.4 lens, Aperture Priority, Manual WB,
Default Parameters (Standard PS), High ISO NR (Default; Off), JPEG Large/Fine
Olympus E-520: Olympus 50 mm F2.0 Macro lens, Aperture Priority, Manual WB,
Default Parameters (Normal), High ISO NR (Normal), JPEG Large/Fine
Nikon D60: Nikkor 50 mm F1.8 lens, Aperture Priority, Manual WB,
Default Parameters (Normal), JPEG Large / Fine

Pentax K200D ISO 100	Canon EOS 450D ISO 100	Olympus E-520 ISO 100	Nikon D60 ISO 100


Pentax K200D ISO 200	Canon EOS 450D ISO 200	Olympus E-520 ISO 200	Nikon D60 ISO 200


Pentax K200D ISO 400	Canon EOS 450D ISO 400	Olympus E-520 ISO 400	Nikon D60 ISO 400


Pentax K200D ISO 800	Canon EOS 450D ISO 800	Olympus E-520 ISO 800	Nikon D60 ISO 800


Pentax K200D ISO 1600	Canon EOS 450D ISO 1600	Olympus E-520 ISO 1600	Nikon D60 ISO 1600


			Nikon D60 ISO 3200

The K200D's default output (Bright image mode) is quite heavily sharpened and contrasty. As a result noise and artifacts are being accentuated and you end up with an image that is visibly grainier than the competitors, even at base ISO. Purple chroma noise blotches appear on the scene at ISO 200 and become progressively more intrusive as you go up the sensitivity scale.

On the up-side the Pentax maintains a relatively good level of detail up into higher ISO regions by applying comparatively little noise reduction (even with High ISO NR switched off there is always some 'base' NR). The graphs below confirm the observations we made on our sample shots. Gray luminance and chroma noise measures pretty high on the K200D.

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.

Share:	Facebook	Twitter	Digg	del.icio.us

Actions:	< Previous	Next >	Print page

Please wait, fetching latest prices.