iso is a norm value for the sensitivity of your sensor, the higher it is your sensor will need less light to form an equal illuminated photo, this has its downside because the higher the iso value means that built imperfections on your sensor will jump up to hence applying noise and reducing detail in your photo (lower iso the better
speeding up your shutter speed will decrease the time during witch the sensor takes in light. the longer it is the more light enters your camera and brighter the photo is, this usually has no effect on image quality, but be aware that slow shutter speed will pick up motion of your hand and cause motion blur.
this is the most common way to control your exposure
another way to control exposure is setting the aperture, the higher the f number, more light enters the camera since the opening in your lens is bigger (and vice verse), this has a side effect of applying different depth of field to your image.
most commonly aperture is used to control depth of field, and than shutter speed gets set for the exposure.
now if you are in a, s or p mode you can dial + or - EV to change your exposure
in p and a mode dialing the EV adjusts your shutter speed (faster or slower) just as you can do it manually.
in s mode you set the shutter speed and the camera will choose aperture, and this might be tricky because dialing EV changes your aperture and affects the depth of field in your image
hope i cleared it a bit
nikon d90 --->af-s dx 18-105mm; tamron 90mm macro
add me up on:
----:>bakice ce vladati svjetom<:----