Also found this useful post on MNSC:
I'll do my best to explain in reqular terms, and I'm sure there are those who know exactly what everything is technically but I'll explain it a bit different.
ISO - Sensor sensitivity if that makes any sense or maybe to explain it as sensor amplification. Generally you want to keep this as low as possible as long as there is light to support it. ISO100-400 is common for daylight etc. If it is dark, you may need to move higher (the higher the ISO is, the more amplification in low light you get, however it also introduces that grainyness to the image)
Aperture - Measured in f/stops (f/1.8,f/2.8 etc etc) lenses with low f/stops (f/2.8 are considered "fast" lenses, and are usually fairly expensive) the fastest most kit lenses are between f/4 - f/5.6. If you look through your lense from not behind the camera, when you see an iris, that is what you are changing when you change the aperture. The lower the f/stop, the more open that iris is, and thus more light can come in. (f/1.2 is pretty much wide open, where f/22 makes just a little pin-hole in the iris) This also affects your Depth of Field (or determines how much is in focus) The lower your f/stop then less will be in focus (say you want someones face perfectly in focus, but everything else blurry, then you want to use the lowest possible f/stop available to your lense) but if you want a picture where mostly everything is in focus, then you want to use a higher f/stop, but remember the higher you go the longer your shutter has to be open, more on that in a minute)
Shutter - basically how long the shutter on the camera is open. measured in seconds or fractions of a second. keep the shutter open longer and you let more light to the sensor, but you must have a fairly high shutter speed if you need to stop any motion. (try for around 1/60th of a second for regular motion, but obviously if something is sitting still, like a car, you can go for longer) The longer exposures are also what give those streaks of light as the camera captures all of the light as the car moves past.
Also if you use a polarizing or other filters, they also reduce the light that is able to come into the camera.
How they all work together - As you can see these all drastically effect exposure in different ways. I typically go for aperture priority on the camera, or manual depending on the circumstances. I almost ALWAYS shoot at ISO 100-200, that way I have minimal noise. That said if it is really dark or something feel free to bump that ISO up as high as you need to, but remember, the higher you go, the more grain/noise your going to get. I like the faster shutter speed (I aim for at least 1/30th of a second) and in order to get those faster shutter speeds I have to use a low f/stop (1.8-2.8) They just all kind of work together.
Low ISO - Less light, less noise - must use a lower f/stop and lower shutter speed
High ISO - More light, more noise - can then use a higher f/stop or faster shutter speed
Fast (low f/stop) Aperture - shallow depth of field, subject in focus, background blurry, can use a higher shutter speed and/or lower ISO
Slow (high f/stop) Aperture - Deep depth of field, everything is in focus, must use a lower shutter speed and/or higher ISO
Fast Shutter speed - Stops motion, lets in less light the faster you need to go
Slow Shutter speed - when used right, gives you light streaks from cars, subject has to be mainly stationary with no movement at all, able to use a lower ISO and/or higher Aperture
An example below. This was shot last week at about 6pm on a snow day (overcast) I shot at ISO 100 (no noise present) f/1.8 (makes the background blur out, she was about 8-10 ft from the wall and I was another 6 or so feet from her) and I was on Aperture priority, and this was 1/60th of a second. so plenty fast enough to stop her natural motion, but not fast enough to stop the snowflakes.
This was taken with a Nikon D80 with a Nikkor 50mm 1.8AFD lense.
Also to make an image "pop" it's a little to do with aperture etc, but mainly in post-processing, and shooting in RAW will help you do this. Images "pop" due to having high contrast/color as opposed to the surroundings/background. Image is usually overly color saturated.
