Chapter 1: It All Starts with the Exposure
All photography is exposure. In essence, a photo is an exposure of the film to light. This section is going to give you an in-depth understanding of exposure. It is going to analyze the three basic elements that make up exposure. By doing so, you will be able to understand how to utilize the right exposure settings for each photo.
How to Produce Exposure
The exposure is produced through a combination of these three factors:
- Shutter Speed
The aperture controls how much light comes into the camera.
The shutter then opens up to allow the light to reach the light sensor or the film.
Thirdly the ISO is used to determine how long the sensor or film needs to be exposed to light.
The aperture is among the three pillars of exposure. By understanding it, you are able to get a more evenly exposed photo. This section will go into detail about how to make use of aperture to your advantage.
Understanding the Aperture
QA good analogy of aperture is the pupil of the eye. As it gets wider, it is able to allow in more light. When the diameter of the aperture increases or reduces, it allows in more or less light. In short, if you want your sensor or film to receive more light, you will increase the size of the aperture.
Measuring and Tweaking the Aperture
The aperture size is measured using the f-stop scale. On cameras, you will find an ‘f/’ symbol and a number. This number is the width of the aperture. The lower this number is, the wider the aperture is set.
The most important thing about this number is that aperture size reduces by half from one number to the next.
Calculating aperture size is quite easy. For instance, if the lens is rated at 50mm and the aperture is rated f2. The width of the aperture is calculated as 50 divided by 2, which is 25mm.
You then have to take the radius (half the diameter), times it by itself (giving the radius squared) and times that by pi. The whole equation looks something like this: Area = pi * r².
How Aperture Affects Exposure
Aperture is directly proportional to the exposure. If aperture is large, it also means the exposure will be more. You can test this by keeping everything else constant except aperture and taking a series of photos.
The Effect of aperture on Depth of Field
Depth of field is all about the distance at which the subject remains in focus in front and behind the focus point. In short, the wider the aperture, the shallower this depth of field will be and vice versa.
The Use of the Different Apertures
There are no hard rules on how to choose aperture. The main influence should be whether you want an artistic effect or you just wish to reproduce the scene accurately in a photo. However, certain apertures are well suited to certain situations:
- f/1.4 – it is often used for low light shooting. It is great for a shallow subject and creating a soft focus effect.
- f/2 – It has the same uses but costs about a third of the price of a f/1.4.
- f/2.8 – It is great for low light situations where definition for facial features is needed. On a good zoom lens, this will be the widest aperture.
- f/4 – This is the minimum aperture that you should use when taking a person’s photo in decent lighting. With a wider aperture, there is the risk of the face becoming unfocused.
- F5.6 – it is best for use when taking photos of two people in good light conditions.
- f/8 – it is great for large groups as it helps to ensure everyone remains in focus.
- f/11 – It is great for portraits as it is where the lens is sharpest.
- f/16 – when shooting in a lot of sunlight, this be the go to aperture.
- f/22 – it is recommended for situations where detail in the foreground is important.
- Keep in mind that these are only guidelines. You can experiment with different apertures to create the effect that you desire.
The contribution of the shutter speed is the most obvious towards exposure. It will also have the biggest influence on the photos you take. If you do not understand shutter speed, you will always end up with blurred photos. This section will guide you on what speed to use for different situations.
Understanding the Shutter Speed
In summary, it is the amount of time, which a camera allows light to reach the light sensor or film. In most photos, you want exposure time to be reduced to a fraction of a second. Any longer and the images may become blurred.
Shutter Speed – The Use of Motion Blur & Freezing
Unless you are trying to be creative, you want the fastest shutter speed to prevent motion blur. This effect is also influenced by a lens’ focal length. A wide-angle lens will need slower shutter speed as it has to capture much smaller details. For a telephoto lens, a fast shutter speed is needed as even slight movement is highly magnified by the lens.
For the best effect, the shutter speed should be set as a fraction of the focal length. For instance, if you are using a 50mm lens, then the shutter speed should be 1/50 of a second. However, this rule only applies to full frame cameras.
For crop sensors, you may need to choose a higher speed such as 1/60 of a second. This is because of its magnifying effect. However, there are exceptions such as image stabilization in the lens. This will allow you to use a much slower speed. As you become accustomed to your camera, you will gain skills such as holding the camera that is comfortable for you.
Freezing takes place when a photo is taken at a shutter speed of 1/500 or more. The photo in that moment is taken without any movement. If you are trying to achieve an artistic effect, this might not be the best speed, as images will feel flat.
For instance, when shooting objects in motion, a bit of motion is needed to capture the movement of the object in the shot. Otherwise, it might as well have been still for the photo shoot.
Choosing speeds for Different Situations
Fast Speeds Using a Telephoto Lens
When working with a Telephoto lens, the shutter speed should be set to 1/500. To avoid shake, use a tripod and remote release. This prevents even slight movements when taking the photo.
Fast Moving objects in Low Light
This is especially common during event photography. The people you are shooting are in constant flux; you now have a situation of low light and fast shutter speeds. To counteract these problems, you will need a wider aperture and a high ISO. It is a compromise but it lets you capture imaged with any unwanted blur.
Use Shutter Speeds for Creative Purposes
The Creative Blur
With a tripod for steady images and a remote trigger to avoid movement, you can mess around with the shutter speeds. You can use to come up with interesting images where blur is the main area of focus.
Combining Flush with Creative Blur
Adding flash and blur will result in the subject being frozen in place. You can then shift the camera to capture blur and light for artistic purposes.
Panning is the process of shifting the camera to compliment the movements of the subject. It results in an image with a blurred background and a clear image.
Light painting only requires slow shutter speed and a good light source. It is a good way to fill in light to certain areas of the frame. It is a nice way to shoot images at night.
With slow shutter speed combined with a moving but constant light source, you can add graffiti to the image.
Low Light Situations and Long Exposure
To achieve this effect, you will need a tripod and a flat surface to lay the camera. It will take some experimenting with the shutter speed to achieve the desired effect.
ISO is among the three pillars that determine photo exposure. To get the most out of a photo, you will need the aperture, ISO, and shutter speed working in harmony. This section provides in-depth knowledge on how to make ISO work for you.
ISO is an acronym for International Standards Organization. It determines the sensitivity of the light sensor or film of the camera. This, in turn, affects the photo exposure. The sensitivity is based on a scale that begins at 100 and doubles onwards. Its upper limit is based on the capability of the camera you are using. The International Standards Organization set the scale of this sensitivity.
The Effect of ISO on Exposure
ISO plays a crucial role if the exposure of a photo. The aperture and shutter speed influence the lens and exposure time. The ISO’s effect is on the film or sensor. The ISO scale is quite similar to the one used for shutter speed. That means a sensor with low ISO will also have low exposure, just like with shutter speed. The ideal sensitivity is usually set at ISO 800. There are many consequences to the different ISO settings.
The Effect of ISO on Photo Quality
In general, the lower the ISO, the better quality of a photo you can get. As the ISO doubles, you double the photo’s exposure. This, in turn, doubles the amount of digital noise expected in the photo. Noise reduces detail, which makes a picture look grainy.
You can carry out an experiment and takes photos at different ISO. You will find out that noise on the photo rises as the number rises. However, some of the noise can be corrected using modern airbrushing software. However, such software should be used in moderation.
Cameras with huge sensors are better at coping with noise. However, as technology improves, the effect of sensor size on noise reduction is becoming less apparent. What used to be a major problem is now much less apparent, especially in high-end cameras.
To discover the ISO limit of a camera, try taking photos with it in low light conditions. Trying to enhance exposure postproduction is the same as trying to increase ISO. Ensure you get it right during the photo session to avoid all of these problems.
Different Situations in Which to Use Different ISO
- ISO 100-200 – This ISO offer the most detail and the highest quality. It is the best for taking photos in daylight, as you do not need to boost ISO. Shooting using ISO 1600 in sunlight would be a major waste, which would lead to unnecessary grain.
- ISO 200-400 – in darker conditions such as in shaded areas or indoors where there is good lighting.
- ISO 400-800 – This setting is best for use when using flash indoors. It leads to even exposure and a detailed background.
- ISO 800-1600 – When doing event photography where there is a lot of motion, this is the best setting. It helps to account for the low light conditions where flash photography is not permitted.
- ISO 1600-3200 – This setting is also used for live gigs. It is especially so where there are very low light conditions and a tripod is not allowed. Beyond this setting, digital noise can be hard to cope with.
- ISO 3200+ – This range is useful for low light where an artistic effect is desired. As with most photos at this high ISO, avoiding digital noise is almost impossible.
This is the end of Chapter 1: It’s All About the Exposure. If you would like to leave us a comment or feedback, please Contact Us today!