Newbie explanation of the relationship between aperture, shutter speed and iso

I always think of it as something like

If you have a bucket and need to fill it with water, the goal is to get the bucket full to the top, you don't want to over fill it or have less than full.

You turn on the tap, so bigger pipe means you only have to turn it on less time til its full. Smaller pipe meaning the tap has to be on longer for it to get full.

So

Light = Water
Aperture = pipe size
Shutter speed = tap opened time

ISO will be the size of the bucket. In this example, then higher ISO = smaller bucket.
 
Last edited:
Raymond Lin said:
I always think of it as something like

If you have a bucket and need to fill it with water, the goal is to get the bucket full to the top.

You turn on the tap, so bigger pipe means you only have to turn it on less time til its full. Smaller pipe meaning the tap has to be on longer for it to get full.

So aperture = pipe size
Shutter speed = tap opened time

ISO will be the size of the bucket. In this example, then higher ISO = smaller bucket.
Click to expand...

Nice :) Anyone have something like that to explain white balance settings etc to me (i.e a dumbass) :) Just cant grasp it :(
 
There are more links and a brief explanation of aperture, shutter speed and ISO in the sticky. The shortcourses link in there has some stuff on WB, IIRC.
 
I think these days its pretty easy to understand it. You can see the results straight away on a digital camera. On film it really was a hard concept to grasp, or should I say an expensive concept to grasp. Photography in those days really was a skill, it still is but the technical side has been dumbed down, if doesnt work, repeat; with film you didnt have that luxury.
 
Film was just as easy really. Because you could only ever change your shutter speed and aperture.. Once your 400ASA film was in you were shooting at 400! Then you just had to know Brighter days = Lower Asa, darker days = higher Asa. Sure you didn't see the results straight away but DSLRs now give the user so many options it can be a learners nightmare!
 
It's been fairly easy since someone invented AE modes.

The thing to grasp is the relationship between Aperture and depth of field, and Shutter speed and motion. Exposure is just maths, the art is in that previous bit. (having said that you will need to know what situations will fool the AE calculations)
 
Raymond Lin said:
I always think of it as something like

If you have a bucket and need to fill it with water, the goal is to get the bucket full to the top, you don't want to over fill it or have less than full.

You turn on the tap, so bigger pipe means you only have to turn it on less time til its full. Smaller pipe meaning the tap has to be on longer for it to get full.

So

Light = Water
Aperture = pipe size
Shutter speed = tap opened time

ISO will be the size of the bucket. In this example, then higher ISO = smaller bucket.
Click to expand...

Exactly the same analogy as I usually use :)
 
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