One of the main things that the S100FS offers that a DSLR would really struggle with is the shear reach of its lens. It's a 14.3X zoom but, more importantly, it's a zoom that starts at 28mm (equivalent), before stretching on to a slightly comical 400mm equiv. For those of us that struggle to convert equivalent focal lengths into angles of views (and you're in the company of most humans if that includes you), then below is a real-world example.
|28mm (equiv.) Wide||
|400mm (equiv.) Tele|
Thankfully the S100FS, unlike its S9X00 predecessors, benefits from lens-shift image stabilization. With a lens equivalent to 400mm, you'd traditionally need expect to need a shutter speed of 1/400th of a second to be sure of getting an unshaken shot (which is a problem, as the long end of the lens usually has a smaller maximum aperture, letting in less light and demanding slower shutter speeds). So how much difference does the S100FS's image stabilization make?
The stabilization test
In this simplified version of our SLR IS test, eight hand-held shots were taken of a static scene with the stabilization off and on. The shutter speed was decreased by a third of a stop and repeated (from 1/200 sec to 1/13 sec). The zoom was set to its maximum position (400mm equiv.), the test chart was 4.5 m away from the camera. This procedure was repeated ten times.
The resulting images were then inspected and given a blur score - 'Sharp' (no visible blurring at 100%), 'Mild Blur' (the kind of camera shake that is tolerable at small print sizes) 'Heavy Blur' (unusable due to camera shake) and 'Very Heavy Blur' (little discernible detail).
As the charts below show we were able to get a measurable one and a third stop advantage. More importantly we were able to get 'usable' results around half the time at shutter speeds of 1/60th of a second, rather than the one-in-ten hit rate we could manage hand-held.
Hand-held, no stabilization (400 mm equiv.)
As you can see from the chart below once we dropped to below 1/100th second we had little or no chance of getting a perfect shot, and only at 1/200th second were we guaranteed of a sharp result every time.
Image stabilization on (400mm equiv.)
FujiFilm continues to use the term 'Dual IS,' which is a usually a combination of physical (lens or sensor-shift) IS and automatic boosting of the sensitivity (ISO) to keep the shutter speed up. We tested the camera with ISO locked at 100 so that the test reflected your chance of getting a sharp image at the best image quality. Oddly, the camera continues to insist that 'Dual IS' is being turned on, even though one aspect of it is suppressed.
Pedantry aside, the IS system proves pretty useful, allowing you to regularly get sharp shots several shutter speeds slower (about 1.3 'stops') slower than just by hand holding. There are two modes of IS - continuous and shooting only. Mode 1 constantly tries to keep the image stable, while Mode 2 only activates as you take the shot. There's little difference between the two modes in terms of effectiveness but, although it has a greater impact on battery life, we prefered Mode 1 simply because it stabilizes the image on the LCD or viewfinder.