I feel like this is a dumb question, but I need to know.

[AprilEye]

When someone tells you that you should shoot a picture at a certain "Stop" what exactly does that mean? Like "you should up your stop" or something to that effect? Is it just another way of describing the aperture or F-stop?

[Ads]

[Bitter Jeweler]

Yup, you got it!

You can also "stop down" your lens.

[sobolik]

A stop is a combination of shutter speed and aperture. Lets say you have a board with a 1 inch hole in it. That could be called a stop. A hole that lets twice as much light through is a different stop etc. "a stop" is a means of communicating an amount. It gets more complicated but that is the basics.

It gets more complicated but like driving a car you don't need to know all the physics around why the car goes faster. You just need to know when you press that foot thing...

"In photography, stops are also a unit used to quantify ratios of light or exposure, with one stop meaning a factor of two, or one-half. The one-stop unit is also known as the EV (exposure value) unit. On a camera, the f-number is usually adjusted in discrete steps, known as f-stops. Each "stop" is marked with its corresponding f-number, and represents a halving of the light intensity from the previous stop. This corresponds to a..."
http://en.wikipedia.org/wiki/F-number

[sanpan]

When we speak about f-stops, its just about aperure settings,right?.
But when we speak about a stop-up or down, we are talking about general exposure levels.
So basically when some one asks to try for a stop up or down, you can either change the aperure or shutter speed (or ISO). This is my understanding.

[AprilEye]

You can also "stop down" your lens.

ok...now how exactly to you do this?

[Bitter Jeweler]

You make your aperture smaller.

Sanpan, you are correct as well.

It is a unit of measure, and all things are equal.
Although a stop, may be described in different ways, they all talk about an amount of light.

If you take a correct exposure, but you want more depth of field, you could stop down your lens (aperture) 2 stops. To maintain that correct exposure, you can either lower your shutter speed 2 stops OR raise your iso 2 stops.

This is easily the most confusing thing. Once you have that "ah hah!" moment, you'll see it is easier than it sounds.

[Boomn4x4]

Keep in mind that with your camera and most modern digital cameras, shutter speed and aperture are in 1/3rd stops, and ISO is in full stops. So adjusting your shutter speed or aperture one "click" is not the same as one "stop" If you go from f/5.6 to f/6.3, you are going 1/3rd of a stop.

Its easy to remember stops on ISO and shutter speed because you simply double (or halve) the number. ISO 200 -> 400 is one stop. Shutter speed 1/250 -> 1/500 is one stop. But aperture isn't so easy, you pretty much just have to memorize them 1.4, 2.0, 2.8, 4.0, 5.6, 8, 11, 16, 22, 32 are your whole stops

[Dao]

It is pretty much the EV (Exposure Value).

Go here (http://en.wikipedia.org/wiki/Exposure_value), scroll down and take a look at the EV table. The far left column is the EV. When you jump from one row to another row such as one above it, it is one stop.

As you can see, if you keep the shutter speed constant, you need to change the aperture setting and vice versa.

[Hannah2]

Keep in mind that with your camera and most modern digital cameras, shutter speed and aperture are in 1/3rd stops, and ISO is in full stops. So adjusting your shutter speed or aperture one "click" is not the same as one "stop" If you go from f/5.6 to f/6.3, you are going 1/3rd of a stop.

Its easy to remember stops on ISO and shutter speed because you simply double (or halve) the number. ISO 200 -> 400 is one stop. Shutter speed 1/250 -> 1/500 is one stop. But aperture isn't so easy, you pretty much just have to memorize them 1.4, 2.0, 2.8, 4.0, 5.6, 8, 11, 16, 22, 32 are your whole stops

This was really helpful - thanks!

[Dao]

Keep in mind that with your camera and most modern digital cameras, shutter speed and aperture are in 1/3rd stops, and ISO is in full stops. So adjusting your shutter speed or aperture one "click" is not the same as one "stop" If you go from f/5.6 to f/6.3, you are going 1/3rd of a stop.

Its easy to remember stops on ISO and shutter speed because you simply double (or halve) the number. ISO 200 -> 400 is one stop. Shutter speed 1/250 -> 1/500 is one stop. But aperture isn't so easy, you pretty much just have to memorize them 1.4, 2.0, 2.8, 4.0, 5.6, 8, 11, 16, 22, 32 are your whole stops

This was really helpful - thanks!

I do not know if other cameras are the same. But mine is, if I turn 3 clicks on aperture, I just need to turn 3 combine to the others (shutter speed and ISO) the opposite way.

i.e. I close down the aperture by 5 turn clicks. In order to keep the same EV, I can decrease the shutter speed by 5 turn clicks or decrease the shutter speed by 1 and the increase the ISO by 4 or any other combination of 5 turn clicks. In that case, I really do not need to remember it especially when it is 1/3 of a stop type setting (hard to remember).

[Fleetwood271]

You make your aperture smaller.

Sanpan, you are correct as well.

It is a unit of measure, and all things are equal.
Although a stop, may be described in different ways, they all talk about an amount of light.

If you take a correct exposure, but you want more depth of field, you could stop down your lens (aperture) 2 stops. To maintain that correct exposure, you can either lower your shutter speed 2 stops OR raise your iso 2 stops.

This is easily the most confusing thing. Once you have that "ah hah!" moment, you'll see it is easier than it sounds.

To add to this, you could set your camera to aperture f/2.8 with a shutter speed of 1/1000 sec, or set it to f/4 with 1/500 sec, and both would be technically the same as far as "quantitative value".
You could keep going with this exercise and change your camera to:
f/5.6 for 1/250
f/8 for 1/125
f/11 for 1/60
f/16 for 1/30
f/22 for 1/15
While each of this would be technically the same, as far as how much light would be allowed to reach your sensor, you would find that the Depth of Field would change greatly from a f/2.8 @ 1/1000 to a f/22 @1/15.

Depending of how much you want whatever is behind your main subject, in focus, or out of focus, you can choose the aperture you want to acheive that in your shots. With an aperture of f/2.8, the background will be very blurry and out of focus. With f/22, it will be sharply in focus. All f-stops in between will vary between.

Good Luck! And don't be afraid to experiment.

[KmH]

At it's simplest a stop is a doubeling or a halving of an amount.

As mentioned, stops can be related to aperture, shutter speed, or ISO.

If you change one of the exposure triad values, to maintain the same exposure you must also change one of the other 2 an equal amount, stops wise.

Lens aperture numbers are kind of odd because when aperture is changed we are changing the area of the lens opening. Consequently, double or half the area (as opposed to the diameter) is a function of the square root of 2 (1.4142135623).

So starting at f/1, the next full stop is 1 x the square root of 2 or 1.414 = f/1.4
f/1.4 x 1.414 = 1.9796 or rounded - f/2
f/2 x 1.414 = 2.828 or rounded - f/2.8
f/2.8 x 1.414 = 3.9592 or rounded - f/4

and so on and so forth.

[AprilEye]

At it's simplest a stop is a doubeling or a halving of an amount.

As mentioned, stops can be related to aperture, shutter speed, or ISO.

If you change one of the exposure triad values, to maintain the same exposure you must also change one of the other 2 an equal amount, stops wise.

Lens aperture numbers are kind of odd because when aperture is changed we are changing the area of the lens opening. Consequently, double or half the area (as opposed to the diameter) is a function of the square root of 2 (1.4142135623).

So starting at f/1, the next full stop is 1 x the square root of 2 or 1.414 = f/1.4
f/1.4 x 1.414 = 1.9796 or rounded - f/2
f/2 x 1.414 = 2.828 or rounded - f/2.8
f/2.8 x 1.414 = 3.9592 or rounded - f/4

and so on and so forth.

Thank You. Aperture = Math. Whoa.

[Raian-san]

At it's simplest a stop is a doubeling or a halving of an amount.

As mentioned, stops can be related to aperture, shutter speed, or ISO.

If you change one of the exposure triad values, to maintain the same exposure you must also change one of the other 2 an equal amount, stops wise.

Lens aperture numbers are kind of odd because when aperture is changed we are changing the area of the lens opening. Consequently, double or half the area (as opposed to the diameter) is a function of the square root of 2 (1.4142135623).

So starting at f/1, the next full stop is 1 x the square root of 2 or 1.414 = f/1.4
f/1.4 x 1.414 = 1.9796 or rounded - f/2
f/2 x 1.414 = 2.828 or rounded - f/2.8
f/2.8 x 1.414 = 3.9592 or rounded - f/4

and so on and so forth.

Thank You. Aperture = Math. Whoa.

Unfortunately

[Dominantly]

Oh Stop it..........

I also have a demo in my signature relating to this.