JPEG 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 (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. Room temperature is approximately 22°C (~72°F), simulated daylight lighting.
|Ricoh GXR/P10||Casio EX-FH100||Panasonic ZS7||Ricoh CX3|
The Ricoh GXR may so far be a unique concept in the digital camera world but if you combine the GXR body with the P10 28-300mm module what you get is pretty much a typical 'Travel Zoom' camera. In this comparison we've therefore looked at the P10 28-300mm images next to the output of three representatives of the Travel Zoom category - the Casio EX-FH100, the Panasonic ZS7 (TZ10 in Europe) and Ricoh's own CX3 which according to Ricoh has a lot of components (including the sensor) in common with the P10 28-300mm.
All four cameras do a decent job at their base ISO but, as you would expect from cameras with very small sensors, things get worse pretty quickly as you go up the sensitivity scale. The P10 28-300mm module performs quite well up to ISO 400 but at higher sensitivities noise, artifacts and noise reduction take their toll. Having said that none of the cameras in this test are much good at ISO 800 and above. With noise reduction 'switched off the Ricoh strikes a relatively good balance between detail retention and noise reduction and even the highest ISO settings should be usable at small output sizes. The other three cameras use slightly more heavy-handed noise reduction which results in more loss of detail and smearing. However, the differences are so marginal that they would only be relevant at very large magnifications. The CX3 is quite close to the P10 28-300mm in terms of image quality at these settings but it also applies more noise reduction and delivers a different color response.
Raw vs in- camera JPEG noise reduction low contrast detail comparison
The GXR/P10 28-300mm has four levels noise reduction - off, weak, strong and max. The crops below show the effects of the off, strong and max settings. We've left out the weak setting as the difference compared to off is negligable. As a benchmark we have also included P10 28-300mm Raw images that have been processed in Adobe Camera RAW 6.1 with all noise reduction options set to zero. Adobe does a degree of noise reduction even when the user-controlled NR is turned off but it is still obvious that 'NR off' on the P10 28-300mm does not really mean 'off' - the raw output has much higher noise levels than all of the out-of-camera JPEGs including the 'NR off' variant. The latter arguably also offers the best compromise between detail retention and noise reduction.
|ACR Raw||NR off||NR strong||NR max|