Small Vs. Large Cameras: Trade-Offs That Come With Different Sizes
Understanding the differences between large and small cameras can help you ensure that you are choosing the best tool for your needs.
When it comes to selecting the most appropriate camera type for your needs, it’s helpful to know the various features that are specific to each style and size offered. Many of our customers have questions about why smaller cameras are often lower in resolution than larger cameras and why larger cameras are known to produce clearer and more detailed images. The size of the lens, the depth of the lens, and the kind of lens are all important factors to consider when determining which camera will be best suited to your particular needs. Most of our clients want the best video quality and the smallest camera posable. While tiny cameras can produce some great video there are tradeoffs that come with small size.
Below we have listed out some of the most common features of the popular large and small cameras that we offer, how those features translate to use cases, and the most common applications of each camera type. Once you are educated about the various uses of the cameras available, you will be better equipped to select the perfect camera for your needs.
Why the Lens Size Matters
When you select a camera, the size of the lens is one of the most important factors to consider. The lenses are divided into two categories:
Monofocal (Fixed Lens)
Varifocal (Adjustable Lens)
The focal length of the monofocal lens is permanently set (fixed lens) which means that the field of view of the camera cannot be changed, or zooming is not possible. If you’re selecting a fixed lens camera, it’s important to make sure that you choose the right field of view to capture what you need to see. The options for this are wide angle and narrow angle lenses.
A wide angle lens camera is the most versatile of the two options as it is able to capture clear, detailed video in any lighting condition (normal, low). Some cameras may be equipped with night vision, IRs, or LEDs to capture video in no-light conditions.
How Depth of Field Affects Your Image Capture
Different camera lenses come in different sizes, as measured by their focal lengths (in millimeters). It’s important for users to understand the difference between various sizes, such as the 2.8mm, 3.6mm, and 12mm lenses. The smaller measurements indicate a wider field of view with less intricate detail, while the larger measurements indicate a narrower field of view but the ability to see a greater distance.
Focal length may vary by camera, including wide angle lenses that can take in entire landscapes to telephoto lenses with optical zoom that can focus in on small subjects in the distance.
The most common lenses for use with security cameras are wide angle lenses as they are best at monitoring large areas like parking lots, yards, warehouses, construction sites, etc.
Other Important Features to Consider When Selecting a Security Camera
While lens size and depth of field are among the most important features to consider when selecting a security camera, there are other criteria as well. It’s also important to consider some of the features of the inner workings of the camera lens, including aperture and iris.
The aperture is the hole that light passes through to enter the camera. You can determine the size of this opening by calculating the “F-stop” or “F-ratio” measurement. The F-stop is a number that indicates the measurement of the lens speed. A simple way of remembering this is by considering that the smaller the number, the larger the aperture size, which means more light is able to pass through to the camera. This feature is used to adjust how much of the scene being captured is in focus: a wide aperture will cause objects in front of it to be focused with a blurry background, while a small aperture will bring everything into equal focus.
Similar to the aperture, the iris also controls the amount of light allowed to enter the lens. Unlike the aperture, however, the amount of light allowed to pass through the iris does not have an impact on the focal points and blurriness of photos and the settings are generally not adjustable. It’s important to choose an iris type that is appropriate for your camera’s location.
Fixed and manual iris lenses are commonly used in indoor settings where the light stays consistent. For example, in offices, schools, or stores.
Auto iris lenses are commonly used in settings where lighting frequently changes, such as in outdoor locations.
Types of Lenses
It’s important to understand the types of lenses and cameras available on the market as well as this is a major contributing factor when it comes to making your selection. Three common types of security cameras on the market are pinhole lens cameras, fisheye lens cameras, and fisheye lens cameras that include dewarping.
Pinhole Lens Camera
The pinhole lens camera is one of the simplest camera types on the market. The camera itself does not actually have a lens at all, but rather is a lightbox with a small hole, or aperture, on one side. Light passes through the aperture and projects an inverted image on the opposite side of the box.
Because the aperture is so small, relatively long exposures are required, making the pinhole camera not ideal for low light conditions. An external IR or LED can aid in low light image or video capture.
Another common security camera style is the wide-angle, or fisheye lens, which has a field of view that encompasses 180 or 360° views. When the images are produced by this type of camera, the result is a round picture with edges are often distorted unless the image has been dewarped. (See next section for more information about dewarping.) These cameras usually feature PTZ, or pan, tilt, and zoom options, giving the user control over what is captured and where the camera is focused. A fisheye lens provides a different view than would normally be possible to capture with only a single camera.
Fisheye Lens Dewarping
Because a fisheye lens generally captures images that are round (due to the extremely wide angle of the lens), a processing technique called “dewarping” is generally needed to make the image viewable. This processes reverses the effect caused by the camera lens and turns the image into a linear picture (essentially, a normal looking picture) that is easy for the viewer to see and understand. If you are purchasing a fisheye lens camera, it’s important that you own the proper photo editing software for viewing the finished product.
Selecting the Best Camera Type for Your Needs
Whether you are using a security camera to capture images in a space with standard lighting, like an office, or an area where lighting is constantly changing, like outside in a parking lot, it’s important that you understand all of the different features and styles of the security cameras on the market so that you can make the most appropriate equipment selection. Choosing a combination of components, including aperture, iris, focal length, and more, will provide you with just the right amount of coverage for your use case.
If you have questions about camera features and components, or need help choosing the most appropriate option for you, we invite you to contact the BrickHouse Security team. We are always here for you when you need to know.
Published on March 1, 2021