Compared to...

Studio scene comparison (high ISO)

Small sensor cameras have always struggled at high ISO settings, with noise - or noise reduction - limiting what you can expect to get as you head up the sensitivity scale. For this comparison ISO 1600 was chosen as it's the highest ISO at which the two Canons can capture full size images (they both have a ISO 3200 mode which produces a much smaller, very soft image). The HX1 has some clever low light tricks that we'll explore further in its full review; for now we're only interested in how it compares at its normal high ISO settings.

What can be seen from these results is that noise reduction has smeared the image so much that a lot of fine detail is lost. Although the differences are small (and are mainly a matter of taste), the SX1 IS is probably the worst of the four cameras here, with a significant loss of fine, low-contrast detail. What is interesting is that the SX1 IS actually does a worse job with noise reduction then the SX10 IS, which manages to retain fractionally more fine detail.

With for all these cameras, ISO 1600 should be considered emergency only options, when it is better to have a soft and blurry picture than none at all, and for small prints or reduced-size on-screen use (such as in a web gallery).

ISO 1600

Canon PowerShot SX1 IS Canon PowerShot SX10 IS
Sony DSC HX1 Panasonic Lumix FZ28

Canon PowerShot SX1 IS High ISO JPEG vs RAW

Canon PowerShot SX1 IS ISO 800 JPEG Canon PowerShot SX1 IS ISO 800 RAW
Canon PowerShot SX1 IS ISO 1600 JPEG Canon PowerShot SX1 IS ISO 1600 RAW

From the RAW image we can see just how much noise the camera's processing is having to deal with, even at ISO 800. The noise is mostly chroma noise, which is going to be noticeable even in small prints, but is fairly easily removed in post processing. Whether you'd end up with anything considerably better than the out of camera JPEG results is questionable (there's certainly a little more detail in the ISO 1600 RAW file than you get in the JPEG, but it is pretty much swamped in noise).