1.) What we mean by ISO is the amount of light we allow in the photo. If we allow too much light in then the photo will come out more clearer and if we allow little light in then the photo will come out more darker and more granier. If you change the aperture to 100 then the photo will come out more granier but if you change the aperture to 1600 it'll come out more clearer.
ISO:
before I edited it!
after I edited it!
Shutter speed:
before I edited it:
After I edited it!:
the low shutter speed effects the motion blur in the image , a high shutter speed will make everything much clearer even if there is motion, it will be in focus at the same time everything will be in-focus.
3.) Shutter speed is a measurement of the time the shutter is open, it's also shown in seconds or a fraction of a second. If you time it perfectly then you'll caption your photo in a perfect freeze frame.
2.) It refers to the lens diaphragm in which it determines how much light you're passing through the camera. It's calibrated by the f/stop and the numbers 1.4,2, 2.8,4. 5.6, 8, 11 and 16. Once you've taken your photos it will become more clearer with the different f/stop you're using.
aperture:
Before I edited it:
After I edited it:
