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Photography Question 
Kasandra  Torres
 

Combining Aperture and Shutter Speed


I don't understand how to combine aperture and shutter speed.


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8/20/2004 7:56:04 PM

 
Brenda Tharp
BetterPhoto Member Since: 6/9/2003
  Kasandra, aperture and shutter have a relationship to each other that gives you the correct exposure when you make the picture. Camera meters are designed to measure a certain amount of light, and you must set the shutter and aperture to expose your film or sensor correctly. Many modern cameras will do this automatically, in certain settings, but they are not always accurate and you must learn to understand when to override the settings to get a great picture.

I would suggest a basic course on photography and using your camera's controls, as your question tells me that you are not certain of what a camera can really do to help you make better photographs. I do not teach a basic one, but there are several offered through this site. "Getting Started" by Jed Manwaring is a very good one, and there are others, too. Hope this helps you!


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8/21/2004 1:59:16 PM

 
Steven Chaitoff
BetterPhoto Member Since: 6/22/2004
  Kasandra, I've got an awesome analogy that is really helpful and can go a long way relating to photography. I think it's pretty popular ... maybe they teach it here at BetterPhoto. Here goes:

An exposure is like a bucket filling with water from a faucet above. Film is the bucket. Light is the water. Now you start with an empty bucket and the goal is the fill it to the brim by turning on the faucet. If you don't fill it enough - that's an underexposure - the shot is too dark. If you overflow it, the shot is too bright.

So you have two controls in your arsenal for filling up the bucket appropriately. First is how long you leave the faucet on, which is analogous to the shutter speed. Second, you can control the size of the flow. You can have a little dribble coming out - a tiny aperture - or you can turn it on full blast so a lot of water comes out at once. The latter is a large aperture.

So to fill the bucket to the top you could let a little dribble flow for a really really long time, which is a small aperture with a long shutter speed. Or you could blast the water out for a quick time, which is a large aperture and a fast shutter. Or you can do anything in between - just as long as the combination will fill the bucket up.

Now say you let the water dribble out for a very very short time. The bucket won't be full at all, just a puddle at the bottom. So your picture will be extremely dark and unsatisfactory. That's why you have to be careful not to use a small aperture and a fast shutter together. Likewise, a large aperture and a slow shutter will have water seeping all over the floor.

So that's basically it. There's film speed too. A slow film like ISO 50 would be analogous to a very large bucket. A fast film like 1600 would be a very shallow bucket ... more like a frying pan. This way you simply don't need very much water no matter what combination you use. So you can work with smaller apertures or faster shutters to get more depth of field or freeze action. But that's as far as this well crafted analogy goes ...


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8/21/2004 9:47:48 PM

 
Dennis Creaghan   Kasandra, You sound as if you're just getting started and if I may offer some advice, I think the greatest favor you can do for yourself is to take Bryan Peterson's course "Understanding Exposure" at this website. It's a great course which will answer all your questions and get you started of on the right foot. I took it and it's great


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8/24/2004 8:25:11 AM

 
L. Francis   Kasandra, I know where you're coming from, but I think I can help you out.

Remember what your camera is and how it works. Your camera is a little box that allows you to take pictures by exposing light to the film inside it. If you expose too much light to the film, the pictures will come out faded. If you don't let in enough light, the pictures come out dark.

OK-- to your aperture/ speed question. Your camera (box) lets in light through two controls: one, the aperture size (a hole that opens at various widths) and the speed, something that determines how slow this little *door* slides open and shut to allow the film to be exposed a certain amount of time.

Now these two ways of bringing light to your camera work together, so a dynamic exists in terms of compensation, that works much like a scale. If you set your camera to a small aperture size where the light meter says there is not enough light, you will have to compensate for this by selecting a slow enough speed where a combination of it and the aperture size will *work.*

The opposite is true. Let's say you select a really fast speed when taking a picture (the door opens and shuts really fast, letting a minimun amount of light go through). And let's say that your light meter says, "Uh uh. At this shutter speed, 1/1000 won't allow enough light to expose the film properly." You will have to compensate for this by opening your aperture wide enough where there's a balance. So generally, the smaller the aperture, the slower the speed you'll need. The larger the aperture size, the faster the speed you'll need.

It's all about balance. I think Kodak put out a very good book on this. You might want to check it out.


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8/27/2004 1:31:24 PM

 
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