Digital cameras are hardware input devices that take still images. The majority of digital cameras are also capable of taking video footage that includes audio. I will refer to older, non-digital cameras as film cameras.
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1. Categories
1.1 DSLR
Digital Single Lens Reflex (“DSLR”) cameras look similar to the traditional professional film camera. They have detachable lenses so a range of lenses can be used depending on shooting conditions.
Traditional camera settings such as f-stop and ISO are emulated and are fully configurable, although an automatic mode is also available.
1.2 Point-and-shoot
Generally intended to be more portable, point-and-shoot models are smaller and comparatively less expensive than DSLR cameras. High-end models are still extremely capable of quality images and video and offer a wide range of features.
1.3 Smartphone
Most smartphones have front and rear cameras. The front camera is generally smaller and less capable & is generally for taking “selfies” and for “video chat” (Facetime, etc).
1.4 Action cameras
Action cameras are small devices capable of capturing high-quality still images and video footage.
The range of GoPro cameras, capable of capturing video and audio, small enough to be attached to a person or piece of equipment, are waterproof and shockproof.
1.5 Webcams
Laptops and even many PC monitors have built-in webcams (webcam is a portmanteau of the words web + camera). Separate webcams can be purchased and connected to devices with the benefit of placing the camera at various angles and positions.
Webcams are crucial to teleconferencing.
2. Specs
2.1 Lens
Larger lenses capture more light which improves image quality and detail. Different lenses can be used for example: telephoto, macro, wide-angle, fisheye.
2.2 Sensor
The camera sensor records the image. Camera sensors are referred to as CMOS sensors [1] as they are based on MOS technology.
The sensor has discreet pixels. Think of these pixels as individual cells that can detect the intensity of the light they are exposed to. The more pixels, the clearer the image — to a point! More pixels mean smaller pixels, and pixels that are exceedingly small introduce side effects (called noise) which make images less clear.
A sensor is an analogue device. The data captured is digitised. The information about the intensity & colour recorded for each pixel as well as the position of each pixel is stored digitally so that it can be recreated later to recreate and output the image.
2.3 Zoom
Optical zoom is affected using a zoom lens which physically magnifies the image. Digital zoom is like zooming in on an image on your PC or smartphone — zoom in too far and the image will pixelate
2.4 Resolution
The number of pixels that make up each image. Typically, between 10 & 30 MP.
2.5 ISO Rating
ISO refers to an organization. In photography, the specific standard is ISO12232:2019.
The International Organization for Standardization (“ISO”) rating for a film camera described the different types of camera film that could be loaded into a camera; the rating described how sensitive the film was to light.
In a digital camera, it describes how sensitive the camera sensor is to light. [2]
2.6 Storage
Image files are stored on an SD card, the capacity of which is measured in Gigabytes.
3. Geolocation
Digital cameras are often equipped with GPS hardware. A GPS-enabled device will be able to embed the exact GPS coordinates of the location where a photo was taken to the metadata of the image file. This is known as geotagging.
This has recreational as well as scientific & commercial applications. It should also be considered as a privacy and security risk.
4. Comparison
| Old film camera | Digital camera |
|---|---|
| Images must be developed first | The film spool had to be changed |
| Spools had 36 exposures maximum | Take many, many photos (depending on storage & resolution) |
| Images must first be developed before they can be scanned & digitised | Images are recorded digitally & can be emailed/transferred/uploaded/shared immediately |
| No video capture | Almost all have video capture |
| Film spool had to be changed | Colour & black & white modes |
| High-quality images/High-resolution images | |
| Can zoom in. | |
| Different lenses can be attached | |
| Portable | |
References:
- Contributor, T. (2018) What is CMOS sensor?: Definition from TechTarget, WhatIs. TechTarget. Available at: https://www.techtarget.com/whatis/definition/CMOS-sensor (Accessed: 29 January 2024).
- Hill,A. (2024) What is Camera ISO? Simple Photographer Guide, Shotkit. Available at: https://shotkit.com/what-is-iso/ (Accessed: 5 April 2024).
- ISO 12232:2019 (2024) ISO. Available at: https://www.iso.org/standard/73758.html (Accessed: 5 April 2024).