At base ISO and up to ISO400 the Sigma delivers some outstanding resolution. Even at ISO400 though, the Quattro starts to show signs of weakness. I am fairly certain that most buyers aren’t looking at the DP1Q for its ability to handle noise at high ISO. The Sigma shines at ISO100 and ISO200 and that’s where most will use it, but there are going to be times when you may need to stretch it up to 800.
It is not a complete loss if you need to move up to 1600, but I would probably reserve 1600 for black and white developing. The images below were converted from raw X3F files with the default settings in Sigma Photo Pro 6.2.
In the end, I’m only going to shoot the Quattro at 100, 200 and 400 ISO and will save ISO800 for emergencies.
Here we are at the native ISO of 100.
ISO400. In comparison the to 100 and 200 ISO images this images still retains most of the detail and nearly identical color values as the 100 and 200 ISO images.
The ISO800 image here is showing more noise in the darker regions of the image. The color and detail are mostly still intact.
By ISO1600 the image’s color has just started to fade, but still there is still detail available.
Things are beginning to fall apart in a big way now. The color has taken an obvious hit and the detail is lacking. Banding is just starting to show up here.
Well, there’s not much to say about this ISO6400 image that’s not immediately visible.