Most beginners take pictures by selecting the creative modes on their cameras but few ever venture into any of the other modes like Aperture Priority, Shutter Priority or Manual mode, perhaps based on fear.
Hopefully the following entry will help simplify things, remove that fear and help you in learning how to shot your camera in manual mode. You will need to know how to set your camera's ISO, shutter speed and aperture settings to do this and in doing so you will get better pictures.
The Exposure Triangle
Every picture you create requires an exposure that consists of three different adjustment settings, the ISO, shutter speed and aperture. These three things make up the Exposure Triangle. Adjusting one will have an impact on the other two.
ISO or ASA
ISO controls how sensitive your camera's image sensor is to light. It will also control how much noise or color grain it will have.
ISO ranges vary for different manufacturers but generally you will find settings that follow 100, 200, 400, 800, etc. The lower numbers being less grainy and less sensitive to light and as you move up being more grainy and sensitive to light. Always try to shoot at the lowest ISO setting possible.
At higher ISO settings you will be able to set faster shutter speeds or a narrower aperture setting. With today's camera makers improving sensor technology, you will be able to get an acceptable level of noise in a image at a ISO setting of 800 or above. Only noticeable when enlarging your pictures beyond 8x10. So don't be afraid to raise your ISO setting.
If the subject is not moving, and if I can, I will always try to shoot with a tripod to keep my ISO setting low. I will have to select a slower shutter speed but the image will have less noise.
Here are a cross section of a photograph of a barn taken at Sweetfields Farms in Masarytown Florida. As you can see the bottom photo has more color noise at 1600. Click on images to enlarge.
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| ISO 100 |
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| ISO 1600 |
Exposure time or shutter speed is the length of time the shutter is open allowing light to hit your camera's sensor. This length of time is measured in seconds or fractions of a second. Most often you will creating an exposure in fractions of a second.
What is the shutter?
The shutter is a curtain that is located in front of the camera's sensor. It is always closed, except when the shutter button is pressed. It is at that time when it opens and exposes the sensor to light and closes again.
What should the shutter speed be set to?
The answer to depends on what are you trying to achieve in your image. Do you want to freeze or blur the motion? Shutter speed is responsible for the blurring motion effect or freezing the action. A fast shutter speed will freeze the action at about 1/500th of a second but will require a wider aperture (more light) or higher ISO (more sensor sensitivity to light) to expose the image correctly. Slow shutter speeds will have more light captured by the sensor and will create an effect of motion blur. Depending on what you are shooting this might be a desired effect.
How do you stop a 90 plus mile an hour fast ball? Here is one of my favorite players from the Tampa Bay Rays, Evan Longoria. In the photograph below I wanted to show the player in action with the movement of the bat as he was ready to hit the pitch. The picture was taken at 1/125th of a second.
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| Evan Longoria from Tampa Bay Rays. 170mm, f/5.6, ISO 400, 1/125th sec |
Aperture
The Aperture, consisting of a series of blades called the diaphragm, can be adjusted to control the amount of light that can pass through the barrel of the lens. The blades create a hole that can vary in size depending on the aperture setting selected by you or automatically by the camera.
Aperture settings are dependent on the lens used. These settings are called f-number or f-stop. You might see the following aperture settings on your camera: f/2.8, f/3.5, f/4, f/5.6, f/8. etc. In this case f/2.8 is the widest opening with all others becoming relatively narrower. These numbers are fractions. So you can see that 1/2.8 is larger than 1/8 for instance. The higher the f-number the smaller the hole created in the diaphragm. At f/2.8 more light will be able to pass through the lens than at f/3.6 because it is a wider opening. Since more light will be coming in through the lens, your shutter speed can be faster at f/2.8 than at f/3.6.
Some lenses are considered to be a "Fast Lens", meaning that they have a real wide aperture setting. For example they can be adjusted to f/1.2 or f/1.4. You can select a f/1.2 aperture with a faster shutter speed and still get a correct exposure. Usually, the lower this aperture value, the more expensive the lens.
The main reason to select the aperture is because it enables you to modify the depth of field. Depth of field is the area in your image that is in focus. Wide aperture = short depth of field. Small aperture = long depth of field. Your eyes automatically adjust to the areas in focus first when looking at a photograph. Controlling the depth of field will guide your viewer's eyes to what you want to highlight thereby removing distractions.
The picture below is from an evening trip to Tarpon Springs, Florida. Tarpon Springs is known for their sponge docks, festivals and Green Restaurants. I wanted everything to be in focus so I used an aperture setting of f/11. The f/11 setting created a broader depth of field.
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| Sponge Dock, 24mm, f/11, ISO 100, 1/15th sec |
Another weekend, another trip to to a new destination. This time it was Sweetfield Farms. Very beautiful place and great place to relax with the family. I used f/3.5 in this photograph because I wanted the sunflower to be the main focus point. The f/3.5 setting created a shallow depth of field.
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| Sunflower, 72mm, f/3.5, ISO 100, 1/1000th sec |
Recommendations
- Practice what you learned in non-critical situations so that you can apply it when needed, which leads to number 2.
- Become familiar with your camera's settings and know where and how to manually adjust the ISO, shutter speed and aperture.
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