ISO is a trade-off between noise and speed. Sometimes you need the speed, like at a nighttime party or sports, and sometimes you need the perfect details, like shooting landscapes.
In general, you want to shoot at the lowest ISO which works in any given situation.
A longer exposure can result in object or camera shake blur. Wider aperture reduces depth of field, making it harder to focus.
Sometimes, you'll need all three to get enough light in the shot: A hot sensor, a longish exposure, and a wide aperture.
In general, you want to shoot at the lowest ISO which works in any given situation.
A longer exposure can result in object or camera shake blur. Wider aperture reduces depth of field, making it harder to focus.
Sometimes, you'll need all three to get enough light in the shot: A hot sensor, a longish exposure, and a wide aperture.