Compared to...

Studio scene comparison (JPEG)

Let's take a look at how the G1 compares to one of the best integrated zoom 'SLR-alikes' on the market, the Fujifilm S100fs, once you move up to a higher ISO setting (at lower ISO settings the differences in the studio are minimal).

This is our standard studio scene comparison shot taken from exactly the same tripod position. Lighting: daylight simulation, >98% CRI. Crops are 100%. Ambient temperature was approximately 22°C (~72°F).

Panasonic DMC-G1 vs. Fujifilm S100fs @ ISO 800

Camera settings:

• Panasonic DMC-G1: Panasonic Vario G 14-45mm F3.5-5.6, Manual Exposure, ISO 800
  JPEG Large/Fine, Manual WB, Default Parameters (Standard), Self-Timer
   
  
• Fujifilm FinePix S100fs: integrated lens, Aperture Priority, ISO 800
  JPEG Large/Fine, Manual WB, Default Parameters (Normal), Self-Timer
  

Panasonic DMC-G1	Fujifilm S100fs
5.5 MB JPEG (4000 x 3000)	5.2 MB JPEG (3840 x 2880)

Although the G1 isn't, strictly speaking, a DSLR it does possess the key attribute that helps DSLRs produce such high image quality - a large sensor. Its Four Thirds sensor is around 0.65 the area of the ones found in the majority of DSLRs, but that's still around four times larger than the chip in the S100fs (which itself is one of the largest in any current compact camera). And that advantage is brought home in this higher-ISO comparison. The G1's image isn't as clean as its output at ISO 100 but it maintains similar levels of detail, still hinting at the horizontal lines on the medals in the third crop. The S100fs is struggling, with fine detail starting to be blurred away and sharpening applied to try to give the impression of a sharp image.

The S100fs is about the best performance we've seen from a small-sensor, integrated lens camera, but it just can't hold up against the G1. Quite simply, as the light levels drop, the larger pixels of the larger sensor are exposed to more photons during any equivalent exposure, making it easier for the signal to overcome noise.