It does has different setting for different scenes, so you think just use those yes? I might do that and just play around with the ISO within each shoot mode, see what differences it makes.
The mode settings are overrides for the auto functions Barry. Sport for example will probably limit how slow the shutter speed drops, guaranteeing that fast moving subjects don't blur. Portrait mode usually opens the aperture wide so that only the thing you focus on, the face will be sharp. So the specific 'modes' are like safety interlocks that help you get those particular kind of shots without being too ham fisted with the settings. Each ISO setting is the equivalent to a position, or 'stop' of the aperture setting. So, if you're set to 100 ISO and an f stop setting of f2.8, if you move to 200 ISO the exposure will change by the same amount as if you changed the f stop to 2.8. It's all to do with the exposure triangle we talked about before. F stops are each individual 'click' controlling the size of the lens aperture. It's a hangover from when it was actually a ring on the barrel of the lens that you rotated. Fully closed it was usually f22 then each click would open it wider, marked as f16, f11, f8, f5.6, f4, f2.8, f2, f1.8 and if you were rich, f1.4. The lowest number, the widest the aperture can go is known as the maximum speed of the lens and is listed as part of its specification. So you can have a 35 to 75 mm f4 zoom lens, a 50mm f1.8 prime lens and a 500mm f5.6 telephoto. The faster the lens, the more capable it is in low light.
