One of our keen-eyed readers named Daniel recently opened up his July issue of Wired magazine and saw this advertisement for the popular Fujifilm FinePix X100. What caught his eye was the following line:
The FinePix X100 provides smooth tonal rendering, an exceptionally low S/N ratio and outstanding image clarity.
S/N stands for “signal to noise” and an “exceptionally low S/N ratio” would mean the camera shoots extremely low-quality, noisy photographs — hardly the thing you’d want to boast about in an advertisement!
Update: Title and tweet fail: we originally wrote “Kodak” instead of “Fujifilm” in the title of this post. Sorry Kodak!
When learning about ISO, you’ve probably heard that the lower the number, the lower the noise and the higher the image quality, but did you know that this isn’t always the case? The reason is something called the base (or native) ISO of a camera — the ISO achieved without amplifying the data from the sensor. This is usually somewhere between ISO 100 and ISO 200. Why does this matter? Bob Andersson of Camera Labs explains:
We all know that using high ISO numbers results in more sensor noise. More surprising, perhaps, is that using an ISO number below the native ISO number also degrades the image.
An interesting example is that when shooting on a Canon EOS 1Ds MkII, ISO 50 has roughly the same signal to noise ratio as shooting at ISO 800. This explains why the lowest possible ISO numbers can only be accessed through custom functions on some cameras.
Know your Base (or Native) ISO (via Reddit)
Image credit: Photograph by Filya1