newb here, wanting to learn about more.

On an DSLR camera, there's aperture, ISO, and EXPOSURE (which is shutter speed). If I change the aperture to the lowest point it can reach on the lens, for example a 50mm lens I own which that can hit 1.8 aperture. I just don't get what's the point in ISO, and EXPOSURE (shutter speed). It's like when I shoot out side, and the SUN is out, what's the difference if I change the shutter speed to really fast like 3000, instead of changing the aperture up to like 10, to reduce light in take. It seems like to me ISO, APERTURE, and EXPOSURE all plays the same role in making the picture brighter or darker... I don't understand when to use this certain type of setting. Could someone please explain to me? thanks..

http://web.canon.jp …g/enjoydslr/par​t2/2A.html

Try reading this post, very helpfull and should answer your questions. Also the book Understanding Exposure by Brian Peterson which is excellent and highly recommended by a lot of folk on here...

https://photography-on-the.net/forum/showthre​ad.php?t=414088

Aperture, ISO, and shutter speed together determine exposure, as you know.
There are a huge number of combinations of these that can give correct exposure, as you also know.
What you are missing is that changing any of these will have side effects NOT related to exposure.

ISO: lower = less noise; higher = more.
Aperture: wider = shallower depth of field; narrower = greater depth of field
Shutter speed: slower = greater blur due to camera or subject motion; faster = less blur

Typically, you should choose the two most important parameters (e.g. DoF and shutter speed), and vary the other (e.g. ISO) to give a correct exposure.

Sometimes, there is just not enough light to achieve this, and a compromise is required, or it may just not be possible to get the shot without more (or, more rarely, less) light.

To give a brief response without sending you after more detailed links; if all you were interested in was a correctly-exposed scene, then you are right, it looks like there is redundancy in the controls available to you. However, your photographic interpretation of the scene may drive you to want a good depth of focus (leading you to choose a small aperture - larger f-number), or to control the appearance of moving objects or minimise camera shake in a handheld shot (leading you to choose a short exposure), or to minimise any digital noise in the image (leading you to choose a low ISO number). The combination of these controls enables you to get the picture you want at a given light level; i.e. they all control exposure by changing a different feature of the final result. Hope that helps. For more information, by all means follow the links.

Try playing with this fun tool to see how each interacts with each other.
http://dryreading.com/​camera/index.html