How do they actually get those breathtaking pictures of waterfalls where the water looks really flowing? And how do they manage to capture the individual drops in a fountain? A photo is created by shining light on the sensor for a certain amount of time. You can find the respective value in the viewfinder or display directly next to the aperture (e.g. 1/60 or 1/800). If we let light shine on the sensor for a longer time, the subject will liquefy when it moves. In other words, we record the path from A to B and get a "blurred" image due to the movement. This can be observed well with a waterfall, for example, when the individual drops of water move from above-down and then along the stream as we take the picture. This works not only with water, but also with a bicycle riding through the picture. A tripod is absolutely necessary for this, since we can't hold the camera steady enough from about 1/60th of a second (of course, individually different). For such motifs, exposure times of several seconds are not uncommon. On the other hand, we can also freeze motion. Let your model splash around in the water with her feet and capture the drops in the air. The moment when the drops are exactly in the air often lasts only 1/1000 of a second, but for that the image looks incredibly surreal, faster than the eye. For these shots we need as much light as possible and/or a high ISO number. I recommend the camera setting TV for this, where you can preset the exposure time. As always, just give it a try. For advanced photographers: Try to combine a long exposure time with a camera movement (dragging). Let a bicycle pass by and try to let the camera follow the movement with a long exposure time. The result will delight after several failed attempts: the background becomes blurred, horizontal lines appear and the bicycle is photographed pin sharp. This also works well with passing cars.
Short exposure time and fast movement - it looks as if the cyclists are sitting on the bike and not moving. If we were to take this photo with a long exposure time, we would only have a blurry ghost tail in the image.