more dumb questions.

[agnatha]

alright, i'm confused.
at the risk of sounding really stupid....
when i'm trying to photograph something that's moving, let's say a duck, do i set the shutter speed high and the aperature low?
let's say i'm outside my house. it's about three in the afternoon. the lighting is good. i want to get my duck howard as he flaps his wings.
he's a pekin, he can't fly, so his flapping is pretty slow. usually i can get some of the detail with my fully automatic camera, but with the new one that allows me to adjust aperature and shutter speed.
the aperature goes from 2.8 to 8
and the shutter speed goes from 2 to 1000.
all of these numbers mean nothing to me, i'm very confused.
i've read and reread how the camera works, the bigger the opening the more light, the more detail, but i'm not just dealing with that. how does that fit in with the shutter speed?
and what the heck is iso?

 

[Robin Usagani]

Cambridge in Colour - Photography Tutorials & Learning Community

 

[Tuffythepug]

I'll try to be brief and not give you more than you can handle right now. It sounds like you are missing something on the aperture; should go to higher numbers like F11 and F16.
First, Shutter speed: For moving subjects you need to set your shutter speed at a relatively "high" number. For the shot you describe I'd say 1/500th of a second should be sufficient. But you could even go to 1/1000 th of a a second if there is enough light. The faster your shutter speed the wider your aperture needs to be in order to compensate. Wider apertures are translated as "lower" numbers because it's a ratio relationship between shutter and aperture ( aperture is referred to as the f-stop)
Every time you adjust the shutter speed 1 stop higher you need to adjust the aperture (f-stop) one stop lower to achieve the same exposure.
Here's an example: If the correct exposure is something like 1/500th second at F8 then the same exposure is achieved with 1/250th at F11 or 1/125th at F16. Your ISO setting will have a dramatic effect on the the correct exposure setting for any given scene.
Think of the aperture as a hole that's letting in light. a small hole lets in a small amount of light but if the hole is left open long enough it will let it as much light as a larger hole !
That is aperture and shutter speed simplified.

 

[jwbryson1]

Let me see if I can help.

Aperture is the size of the opening (or hole) that regulates the amount of light that comes through and hits your camera's sensor in order to record the image. The aperture is formed mechanically inside your camera lens when the shutter opens. The smaller the aperture number (e.g., f/2.8, f/3.5) the LARGER the opening because the number represents a fraction. At this point, you don't need to understand the specifics of that, just remember that it is counterintuitive--a smaller f/stop (f/2.8) means a larger hole and therefore more light comes in to the camera. A larger f/stop (f/16) means a smaller opening and therefore less light.

Shutter speed means just that --- in fractions of a second or whole seconds, it is a measure of how long the shutter stays open. For example 1/250 second or 1/500 second or 10 seconds. The longer the shutter speed, the more light can come in, and vice versa, the shorter the shutter speed, the less light that can come in to the camera.

Now, think about this logically---if you are using a larger f/stop (for example, f/11) (remember, smaller hole, less light), then what will you need to do to adjust your exposure to make sure you get enough light in the camera? LONGER SHUTTER SPEED. Of course. And alternatively, assume you are using a smaller f/stop (e.g., f/2.8) (remember, bigger hole, more light), then what do you need to do to adjust your exposure? That's right---shorter (faster) shutter speed.

ISO is a measure of how sensitive the sensor will respond to light. For example, at a "low" ISO of 100, in a scene with low light, it may be difficult to record the image because the sensor does not pick up the light very well. If you turn up the ISO to a higher number, for example ISO 500 or ISO 1000, the sensor will respond better to the available light and you will get more light in your image. The downside to higher ISO numbers is you will get more image "noise" at higher ISOs. Noise is a grainy look to your photos that can ruin them. More expensive cameras do a better job at eliminating noise at high ISOs.

ISO + Shutter Speed + Aperture make up the "exposure triangle" and all work in unison to form the "correct" exposure for your image.

That's just the tip of the iceberg.

Read the links that Schwetty posted above. They are invaluable.

 

[Buckster]

I'll try to be brief and not give you more than you can handle right now. It sounds like you are missing something on the aperture; should go to higher numbers like F11 and F16.

Not to confuse the issue, but you folks might as well get off on the right foot.

When talking about aperture, we're talking about the hole in the lens that the light has to go through. It's like a sieve hole or the hole in the middle of an hourglass; The bigger it is, the more light comes through per second. If more light comes through per second, you don't need the shutter to stay open as long because you only need x amount of light for the proper exposure.

Now then, here's the tricky part about f/numbers: As an example of what's bigger, f/2 is BIGGER than f/16. Yes, the whole number 16 is bigger than the whole number 2, but f/numbers used in aperture measurements are fractions, like 1/2 and 1/16 and that's why they have that slash in them, like f/2 and f/16 and so on. That f/xx stands for the focal length of the lens, divided by the xx, just like any other fraction.

Everyone knows that a slice of half a pie is BIGGER than a slice of a sixteenth of a pie. Same thing with apertures; f/2 is a BIGGER hole in the lens than f/16, it's a bigger number than f/16, and it lets in more light per second than f/16.

Hope that helps.

 

[agnatha]

that is exactly what i needed to hear. i kept going to google and getting kind of general advice.
i wanted something more specific and each comment was absolutely what i was looking for. not stuff like "set up the shot" kind of stuff. i would hope i already knew that. i'm not THAT lousy at this.
but this is perfect.
unfortunately a big huge cloud just came out of nowhere, but at least i'll know what to do when it goes away even if that's tomorrow.
i'm going to my job where i'll probably get a chance at some good shots of the birds of prey, assuming it isn't raining, so hopefully tomorrow i can post a link to whatever i get.

 

[enzodm]

I'll try to be brief and not give you more than you can handle right now. It sounds like you are missing something on the aperture; should go to higher numbers like F11 and F16.

most likely she has a compact camera, for which f/8 is quite usual as lower limit.
Agnatha: looking at your previous posts, is difficult to understand which camera you have, because while theory is the same, a compact camera (P&S, bridge, etc) leaves you some less freedom.

 

[Tuffythepug]

agnatha, I'm glad that you were able to get the info you wanted from our responses. I think we were pretty much all saying the same thing in different ways. I'm sure you are beginning to grasp what all that shutter and f stop numerology means by now. One more thing that you may find enlightening. every whole step of f stop change and every full stop of shutter speed is letting in either twice as much light or half as much light; depending upon which direction you are headed with the change. 1/500th of a second lets in twice as much light as 1/1000th of a second but only half as much as 1/250th of a second. F stops work the same way; F/8 lets in twice as much light as F/11 but only half as much light as F/5.6 So every time you change 1 stop in either direction you are either doubling or halving the amount of light reaching the sensor.

 

[enzodm]

... and ISO acts the same: 200 needs half the light of 100 for the same exposure, 400 half of 200, etc. With increasing noise.

 

[Phototripper]

If you are trying to get a good handle on how ISO, Aperture, and Shutter Speed all relate with one another, I would recommend trying CameraSim to practice with and use as a learning tool. There is a free online version and a paid version for the iPad, iPhone. The application allows you to change all of the controls on a DSLR camera and then virtually snap the picture, showing the results of your settings as well as providing advice for improvement on the shot. Give it a try at CameraSim | SLR Photography Demystified

good luck

 

[Tuffythepug]

... and ISO acts the same: 200 needs half the light of 100 for the same exposure, 400 half of 200, etc. With increasing noise.

Good point. I should have mentioned the role of ISO in that whole equation

 

[KmH]

FWIW

Take note that the vast majority of people who post here use the shift key to make the appropriate capital letters, because it makes posts more readable.

So does making paragraphs so a post isn't one big block of text.

 

[Rosy]

When talking about aperture, we're talking about the hole in the lens that the light has to go through. It's like a sieve hole or the hole in the middle of an hourglass; The bigger it is, the more light comes through per second. If more light comes through per second, you don't need the shutter to stay open as long because you only need x amount of light for the proper exposure.

Now then, here's the tricky part about f/numbers: As an example of what's bigger, f/2 is BIGGER than f/16. Yes, the whole number 16 is bigger than the whole number 2, but f/numbers used in aperture measurements are fractions, like 1/2 and 1/16 and that's why they have that slash in them, like f/2 and f/16 and so on. That f/xx stands for the focal length of the lens, divided by the xx, just like any other fraction.

Everyone knows that a slice of half a pie is BIGGER than a slice of a sixteenth of a pie. Same thing with apertures; f/2 is a BIGGER hole in the lens than f/16, it's a bigger number than f/16, and it lets in more light per second than f/16.

Hope that helps.[/QUOTE

Buckster, your detailed explanations are always a pleasure to read. THANK YOU

 

[enzodm]

the bigger the opening the more light, the more detail

actually, "the more detail" is not true. Normally a lens is sharpest a couple of "stops" below the maximum. If you wonder how is the correct sequence of f/ numbers: F-number - Wikipedia, the free encyclopedia

 

[480sparky]

the bigger the opening the more light, the more detail

actually, "the more detail" is not true. Normally a lens is sharpest a couple of "stops" below the maximum. If you wonder how is the correct sequence of f/ numbers: F-number - Wikipedia, the free encyclopedia

If one were to actually calculate the 'correct' f/stop numbers, you'll find them (full stops) to be:

1.00
1.41
2.00
2.83
4.00
5.66
8.00
11.31
16.00
22.63
32.00
45.25
64.00
.........


Half Stops are:

1.19
1.68
2.38
3.36
4.76
6.73
9.51
13.45
.............

Well, you get the idea.