Photo Settings A

***Camera Settings in a Nutshell***
by Bryan Pakingan

There are actually a lot of resources you can go to online to learn about how to use a camera, but I will skim over the stuff real quickly incase you don’t want to take the time to surf the web.

In photography, you have your trinity when it comes to settings: Aperture, Shutter, and ISO.

These are pretty much the three things you will be using to deal with exposure so it’s good to have an idea of how each affect your pictures.

I will go through it real quick:

Aperture

Physical Definition: The hole of your lens. Usually the aperture is created by using blades inside the lens that slide to form a hole. Generally the more blades, the more “round” the bokeh appears in out of focus (OOF) areas.

Practical usage: The aperture setting affects your shot because it affects the depth of field of the shot, and it also affects the speed you can take the shot. As you make the hole of the lens smaller, you get more “depth of field” in the shot. The depth of field is basically the range away from the plane of focus that will “appear” to be in focus. So the larger your depth of field is, the farther that range will be from the plane of focus.

If your camera allows it, you can adjust the f/stop of your lens through the camera. The f/stop are the numbers such as 2, 2.8, 4, 5.6, 8, 11, 16, 22, etc.
You can read up how these numbers were figured out online. I will just discuss how the f/stop affects the pictures.

Generally, (and this varies between lens), your depth of field increases as you move up f/stops. Therefore, using the larger numbers like f/22 will yield more depth than lets say, f/8.

Going up the f/stops also slows down the time it takes to properly expose your shot. The numbers I listed above are one full “stops” which means going from 2.8 to 4 cuts your exposure time by half, and going backwards gives you 2x the shutter speed.

For example, if I go from 2.8 to 4, and the shutter speed at 2.8 was 1/500, then the shutter speed at 4 will be 1/250 (because you lose half).

If I want to go from 2.8 to 5.6 you go from 1/500 to 1/250 (2.8 to 4), then 1/250 to 1/125 (4 to 5.6). This would be a “two stop difference.”

If my shutter speed at f/5.6 was 1/125, then going from 5.6 to 2.8 would give me 1/500. Therefore the shutter was increased by 4x because we “opened up” two stops.

This leads to what it means to open up and stop down. Stopping down basically means that you’re making the aperture size smaller (like going from 2.8 to 4). Opening up means you’re making the aperture size larger (like going from 4 to 2.8 )

Shutter

Physical Definition: The shutter speed is basically the time it takes for the shutter to open and close. This is measured in seconds usually.

Practical usage: We already know how the aperture size affects the shutter speed. Therefore, if you choose to adjust shutter speed and let the camera handle the aperture for you, you have the same relationship as we had above.

Basically if I’m at 1/500 and my camera sets the f/stop to f/5.6 for me, then if I set my shutter to 1/250, then the camera will set the f/stop to f/8 for me. If I set my shutter to 1/1000, then my camera wil set the f/stop to f/4 for me. So you see, the relationship holds the other way around as well.

You will just have problems if you maximum aperture size (for your lens) is lets say, f/2.8, and your camera tells you that for a properly exposed picture, you require a 1/100 shutter. Then if you set the camera to 1/200 (opening up 1 full stop), the camera won’t be able to do it because you’re already at your largest aperture. It wouldn’t be able to go any lower than 2.8 and the camera will fail to adjust exposure for you… and in this case, you’ll get an underexposed picture.

The shutter also controls how you freeze motion. Having a fast enough shutter speed can freeze even the fastest moving objects. You can freeze horses or even a ball thrown in mid air if you adjust your shutter speed fast enough. Generally this will be around 1/1000 of a second. You can also allow motion blur by making the shutter slower. Generally anything moving under 1/60 of a second will have blur. You need at least 1/60 to freeze regularly moving things (like people walking at a normal pace).

ISO

Physical Definition: In film, this is the sensitivity of the film you’re using in the camera. The sensitivity is basically how sensitive the film is when it comes to reacting to light. More sensitive film will allow the film to be exposed much more quickly. Basically you need less light to expose that particular film as you would with another film that is “less” sensitive. As you can realize now, the ISO affects the shutter speed as well.

This is measured in stops as well. The “double and halving” concept here is pretty obvious. The general ISO stops are: 50, 100, 200, 400, 800, 1600

The higher you go in the numbers (50 to 100), the more sensitive your film gets. One stop of adjustment in ISO gives you a stop of extra speed in your shutter speed.

In digital, its the sensitivity of the sensor. Film and digital sensitivity are basically alike, but the quality differences as you use more sensitive film opposed to sensors are drastic.

Practical usage: So lets say I want my shot to be at f/2.8, but my shutter is too slow to freeze motion since I’m only getting a shutter speed of 1/40 according to the camera. I check my ISO speed and it says I’m at ISO 100. If I change the ISO to ISO 200, then my shutter speed gets another stop of light to play with, (which is 2x more), so my shutter speed is now 1/80, and now I can freeze motion.

Lets say I was at 1/80 and didn’t want to freeze motion and wanted some blur. I want to keep my f/stop at its max at 2.8, so I can only adjust the ISO in this case. I check my ISO speed and it says ISO 100. If I go down to a less sensitive ISO value, in this case ISO 50, then I lose 2x the light. So I go from 1/80 to 1/40, which should be enough for motion blur.

Therefore, the ISO affects the shutter speed.

So why not use higher ISO then? Well, unfortunately, the more sensitive your film is, the more grainer the shots get. In digital, the more “noisy” it gets. Basically, the quality gets worse in the shots.

Nowadays however, cameras such as the Rebel XT and D80 can handle high ISO noise quite well. Unlike film which is generally horrible at ISO 800, on digital it can look very usable. Digital in general (nowadays) does much better in quality over ISO 800 than film does.

Usually, using extremely high ISOs is only done in specialized situations. (Very dark areas is one example)

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Revised: 12/09/2006