When selecting a camera you will be confronted with a huge variety to choose from with many makes and models available. For this reason it is important to know what features to look for when selecting your camera so you may choose one which meets your needs. You will need to consider a few things such as your expectations from the camera; will you just want it for snap shots or a more serious use, how much you’re willing to pay and what quality you expect from it. Other considerations include whether you will use the camera to create images for printing, and what sized prints you will be creating.
Below is a summary of the different types of digital cameras…
Below is a summary of the different types of digital cameras…
These cameras are the most basic digital cameras. They are small, affordable and simple to use. Digital compacts are light and can be carried in the pocket and are ideal for those who simply want to point the camera at a subject and click a button. Most digital compact cameras lack an optical viewfinder to make room for larger display monitors. Larger monitors allow viewing with more accuracy.
Bridge camera’s are a bridge between the easy to use compact digital camera’s and the high quality DSLR’s, they are in ways a mixture between the two. Compared to the digital compact cameras, these cameras offer faster auto-focus, reduced shutter lag and high megapixel settings to allow for print quality images. The image sensor is also larger than digital compact cameras but smaller than DSLR’s creating a difference in image quality. Like digital compacts, the lens is permanently mounted but the cameras offer a zoom range from wide angle to telephoto making them versatile.
DSLR’s are for the committed photographer willing to make a substantial investment in their equipment. There are entry-level models for amateurs and the more pricey professional ranges available. This type of camera offers interchangeable lenses, large and very high quality image sensors, fast auto-focus and fast image processing capabilities. The optical viewfinder allows the photographer viewing without the risk of light glare from the monitor impairing the photographers view when trying to compose the image.
Entry-level cameras are cheap and often geared towards beginners. Entry digital compact cameras offer small camera bodies with high pixel counts and zoom factors. It is important to note that the smaller cameras mean smaller image sensors. Image noise becomes relatively obvious in such cameras and they tend to perform poorly in low light conditions. Even though these cameras are often small and not cumbersome like some more advanced cameras, they offer lower quality images than their advanced counterparts. This does not, however, mean that entry-level DSLR’s offer poor quality images, the quality remains superior to that of the point-and-shoots and bridge cameras alike.
Entry-level cameras are cheap and often geared towards beginners. Entry digital compact cameras offer small camera bodies with high pixel counts and zoom factors. It is important to note that the smaller cameras mean smaller image sensors. Image noise becomes relatively obvious in such cameras and they tend to perform poorly in low light conditions. Even though these cameras are often small and not cumbersome like some more advanced cameras, they offer lower quality images than their advanced counterparts. This does not, however, mean that entry-level DSLR’s offer poor quality images, the quality remains superior to that of the point-and-shoots and bridge cameras alike.
So What Makes a Good Camera?
There are several things which can effect the quality of a camera including the size of the image sensor, megapixel count and camera software. Other considerations include auto-focus capabilities, shutter lag and zoom.
The image sensor is the heart of the digital camera. The size of the image sensor can affect the crop and the degree of noise expressed on the image. How much background blur you can attain is also affected. A small image sensor will have a high degree of crop, which means that if you take an image with a camera with a small image sensor (e.g. 1/2”), it will show a smaller area of the scene than that of the image taken with the larger image sensor (e.g. 4/3”).
It needs to be noted that in digital photography the focal range of the cameras lens may not be the focal range you actually use. The focal length is always referred to in terms of traditional format when film negative measured 36x24mm (length by height). However, most digital cameras have considerably smaller image sensors so what’s captured in the image is actually different. The extent to which these captured sections differ is called the crop factor, the smaller the image sensor the larger the crop. E.g. a sensor which measures 22.2x14.8mm (length x height) is 1.6 times smaller than a 36mm negative. This means that a 50mm lens would have the effective focal length of 80mm when used with this image sensor. A smaller sensor measuring 5.76x4.29mm would have a smaller factor of 6.25. In this case the 50mm lens would have an effective focal length of 312.5mm! The listing of a digital cameras focal range can be misleading without taking crop factor into account.
Here is an image to demonstrate the correlation between image sensor size and crop factor…
The sensor holds millions of tiny light sensitive diodes which are arranged side by side, the number of pixels they hold determines the resolution, sharpness and contrast of an image. Once light hits these diodes, the image sensor creates an electronic signal, which is processed and optimized by the cameras software.
As the image sensor shrinks the size of the pixels and the space between them must also shrink, this can lead to errors in pixilation. Good camera software can correct this problem to an extent but cannot correct in every instance, nor always correct well. For this reason it is not recommended to invest in a small camera with a large pixel count as it may not provide the quality you were anticipating. So how many megapixel’s should a camera have? In terms of print size, for a full page A4 print 6-8MP is adequate, for small 4x6 prints and for display on a monitor 3-5MP is fine. Large megapixel counts are only really required for large prints and should only be accommodated by a large sensor for good consistent image quality. Megapixel count indicates available resolution and determines the degree of image quality that can be achieved. A pixel is the smallest unit of digital image, the more pixels there are on the image sensor the more information that can be stored for a picture, but overcrowding pixels makes the image prone to error.
Camera software calculates the digital image which is read by the image sensor. Fast trouble free software is important for internal image processing and storage, so a camera with poor software may produce poor images, even with a high pixel count and decent sized sensor. Auto-focus (AF) speed depends on capability of the cameras processor and frequency with which the image sensor sends a signal to the monitor to update the image. Higher quality cameras will transmit over 100 times per second. Shutter lag becomes noticeable in most digital cameras caused by the time it takes for the camera to focus.
As the image sensor shrinks the size of the pixels and the space between them must also shrink, this can lead to errors in pixilation. Good camera software can correct this problem to an extent but cannot correct in every instance, nor always correct well. For this reason it is not recommended to invest in a small camera with a large pixel count as it may not provide the quality you were anticipating. So how many megapixel’s should a camera have? In terms of print size, for a full page A4 print 6-8MP is adequate, for small 4x6 prints and for display on a monitor 3-5MP is fine. Large megapixel counts are only really required for large prints and should only be accommodated by a large sensor for good consistent image quality. Megapixel count indicates available resolution and determines the degree of image quality that can be achieved. A pixel is the smallest unit of digital image, the more pixels there are on the image sensor the more information that can be stored for a picture, but overcrowding pixels makes the image prone to error.
Camera software calculates the digital image which is read by the image sensor. Fast trouble free software is important for internal image processing and storage, so a camera with poor software may produce poor images, even with a high pixel count and decent sized sensor. Auto-focus (AF) speed depends on capability of the cameras processor and frequency with which the image sensor sends a signal to the monitor to update the image. Higher quality cameras will transmit over 100 times per second. Shutter lag becomes noticeable in most digital cameras caused by the time it takes for the camera to focus.
Lenses are Important Too!
Lenses should be of good quality as all the information has to pass through the lens to reach the image sensor for processing and storage, this is especially important with small image sensors of modern digital cameras as the smaller pixels on smaller sensors make it increasingly important to have a good quality lens to help bundle light so that it hits the pixels in an appropriate manner (as perpendicular as possible). High quality lenses also minimize lens reflections.
Optical and Digital Zoom
Zoom offers more flexibility allowing the photographer to take pictures of objects far away. Optical zoom is what the lens is actually capable of, it is manipulated zoom and a result of the change of focal length in the lens. Digital zoom does not change the focal distance in the way optical zoom does, instead it crops the image so it is simply an extract from the image data re-calculated. This causes deterioration of image quality. E.g. if a section is enlarged by 50% the image data is cut in half, producing an image that is noisy, fuzzy and pixelated, therefore optical zoom is preferred.
Focal length is the measurement of the light travelling through the lens from the optical centre to the focus point (where two parallel light beams intersect) on the imaging sensor. It is stated in millimeters (mm) and determines the lenses field of view e.g. 10mm is wide angle (a lot of the scene is in shot – better for photographing large subjects) and 200mm is telephoto (only a small section of the scene is in shot – better for photographing a subject far away).
The “X zoom” which is stated with digital compact cameras is the cameras longest focal length divided by its shortest focal length. E.g. an 18-55mm lens would become 3x Optical Zoom, confusingly so would a 70-200mm lens, which confounds the confusion of what zoom range you’re actually receiving. There isn’t a standard base number that the x Zoom starts from so it’s difficult to know what focal range the camera is with this system. The zoom range, however, does give an indication of how much flexibility the lens has but a high zoom range can also compromise image quality, especially digital zoom. If a camera has 5x optical zoom and 5x digital zoom, this does not equate to 10x optical zoom as the 5x digital zoom will lower the quality of the image.
Macro is the cameras ability to focus on subjects close to the lens (e.g. as close as 1cm) and is independent from the cameras zoom ability. This mode is very useful for photographing small subjects like insects, flowers and small animals.
Focal length is the measurement of the light travelling through the lens from the optical centre to the focus point (where two parallel light beams intersect) on the imaging sensor. It is stated in millimeters (mm) and determines the lenses field of view e.g. 10mm is wide angle (a lot of the scene is in shot – better for photographing large subjects) and 200mm is telephoto (only a small section of the scene is in shot – better for photographing a subject far away).
The “X zoom” which is stated with digital compact cameras is the cameras longest focal length divided by its shortest focal length. E.g. an 18-55mm lens would become 3x Optical Zoom, confusingly so would a 70-200mm lens, which confounds the confusion of what zoom range you’re actually receiving. There isn’t a standard base number that the x Zoom starts from so it’s difficult to know what focal range the camera is with this system. The zoom range, however, does give an indication of how much flexibility the lens has but a high zoom range can also compromise image quality, especially digital zoom. If a camera has 5x optical zoom and 5x digital zoom, this does not equate to 10x optical zoom as the 5x digital zoom will lower the quality of the image.
Macro is the cameras ability to focus on subjects close to the lens (e.g. as close as 1cm) and is independent from the cameras zoom ability. This mode is very useful for photographing small subjects like insects, flowers and small animals.
Summary and Spec Considerations:
Megapixels: Not as important as camera distributors lead you to believe, anything from 5MP is very much adequate for displaying on the computer 8MP for print sizes up to about A4. More MP’s are more useful when creating large prints and using a camera with a larger image sensor.
Zoom: Zoom numbers are a bit vague but generally the bigger the number the more versatility. Big optical zoom numbers are much preferred over digital zoom. Zooms are more useful for those photographing wildlife or other distant subjects.
Focal Length Equivalent: This is useful information for knowing the focal length capabilities of the camera, but the crop factor also needs to be known. Information can be misleading if crop factor is not taken into account.
Image Stabilization (IS): Very useful with cameras that have a long focal range (200mm and above).
LCD Screen: Can vary in size from about 1.8 – 3.5 inches. A larger screen can be useful for reviewing images and deciding if a re-shoot is necessary. Smaller screens make it harder to review for faults.
Viewfinder: Can be useful for composing images without the risk of light glare interfering with your view, but otherwise not vital.
Sensor Size: Sensor size can affect crop factor and image quality, bigger sensors are preferred. E.g. 1” sensor is superior to ½.3” and an APS-C sensor would be better still. Budget is an important factor in how big you can go.
Sensor Type: CCD is most common type of sensor but cameras may instead have a CMOS sensor. CCD’s are generally considered better quality.
File Formats: Jpeg is the standard file format. You may see RAW offered but is only useful if you’re willing to process the image and convert to Jpeg. TIFF may also be seen and is basically an uncompressed version of Jpeg, better quality but extremely large and may need converting to Jpeg as this format is not as widely universal.
Memory Cards: SD cards are most common but other formats include Micro SD, xD and Compact Flash. Consider storage capacity of card and format you will be photographing in, Jpeg is the smallest format, RAW the largest. If shooting with a 10MP camera onto a 1GB SD card; capacity = 286 Jpegs or 28 RAW images. 4GB capacity = 1144 Jpegs or 114 RAW. Be aware that memory cards can become defective so two cards are recommended. Images should be backed up on computer or CD as soon as possible. CD’s may last around 8 years without corrupting.
Continuous Shooting Speed: Measured in frames per second (fps). For sports or action photography 3fps or faster is preferred.
Processor: Different brands use different processors (e.g. Canon: DIGIC, Nikon: EXPEED, Panasonic: Venus Engine etc). If processor is listed check the processors capabilities, a poor processor makes for a poor camera.
Batteries: Some cameras use their own rechargeable brand of battery, others (especially older models) use AA batteries. Battery life and camera cost are not related, some cameras drain battery life rapidly so it’s good practice to have spares to hand.
Shooting Modes: Some cameras have a variety of auto modes (dedicated Macro, landscape, portrait, sport etc). Cameras may also have manual modes (Shutter Priority, Aperture Priority, Full Manual) which gives the photographer partial or complete control over the image. Can be useful when the photographer wishes to control settings (e.g. for a long exposure shot).
Shutter Speed: Fast shutter speed freezes motion and a slow shutter speed captures motion blur and allows in more light. 1/8000 is the fastest needed to capture sporting events. 1/2000 usually adequate for most action shots.
Aperture: Larger aperture is preferred for more light gathering and increased depth of field (e.g. f/2.8 is larger than f/5)
Sensitivity: Refers to ISO. The higher the ISO number the more sensitive the camera is to light so can potentially be useful in low light situations, but higher ISO also means increased noise and poorer picture quality. Noise starts to become apparent after ISO 800.
Zoom: Zoom numbers are a bit vague but generally the bigger the number the more versatility. Big optical zoom numbers are much preferred over digital zoom. Zooms are more useful for those photographing wildlife or other distant subjects.
Focal Length Equivalent: This is useful information for knowing the focal length capabilities of the camera, but the crop factor also needs to be known. Information can be misleading if crop factor is not taken into account.
Image Stabilization (IS): Very useful with cameras that have a long focal range (200mm and above).
LCD Screen: Can vary in size from about 1.8 – 3.5 inches. A larger screen can be useful for reviewing images and deciding if a re-shoot is necessary. Smaller screens make it harder to review for faults.
Viewfinder: Can be useful for composing images without the risk of light glare interfering with your view, but otherwise not vital.
Sensor Size: Sensor size can affect crop factor and image quality, bigger sensors are preferred. E.g. 1” sensor is superior to ½.3” and an APS-C sensor would be better still. Budget is an important factor in how big you can go.
Sensor Type: CCD is most common type of sensor but cameras may instead have a CMOS sensor. CCD’s are generally considered better quality.
File Formats: Jpeg is the standard file format. You may see RAW offered but is only useful if you’re willing to process the image and convert to Jpeg. TIFF may also be seen and is basically an uncompressed version of Jpeg, better quality but extremely large and may need converting to Jpeg as this format is not as widely universal.
Memory Cards: SD cards are most common but other formats include Micro SD, xD and Compact Flash. Consider storage capacity of card and format you will be photographing in, Jpeg is the smallest format, RAW the largest. If shooting with a 10MP camera onto a 1GB SD card; capacity = 286 Jpegs or 28 RAW images. 4GB capacity = 1144 Jpegs or 114 RAW. Be aware that memory cards can become defective so two cards are recommended. Images should be backed up on computer or CD as soon as possible. CD’s may last around 8 years without corrupting.
Continuous Shooting Speed: Measured in frames per second (fps). For sports or action photography 3fps or faster is preferred.
Processor: Different brands use different processors (e.g. Canon: DIGIC, Nikon: EXPEED, Panasonic: Venus Engine etc). If processor is listed check the processors capabilities, a poor processor makes for a poor camera.
Batteries: Some cameras use their own rechargeable brand of battery, others (especially older models) use AA batteries. Battery life and camera cost are not related, some cameras drain battery life rapidly so it’s good practice to have spares to hand.
Shooting Modes: Some cameras have a variety of auto modes (dedicated Macro, landscape, portrait, sport etc). Cameras may also have manual modes (Shutter Priority, Aperture Priority, Full Manual) which gives the photographer partial or complete control over the image. Can be useful when the photographer wishes to control settings (e.g. for a long exposure shot).
Shutter Speed: Fast shutter speed freezes motion and a slow shutter speed captures motion blur and allows in more light. 1/8000 is the fastest needed to capture sporting events. 1/2000 usually adequate for most action shots.
Aperture: Larger aperture is preferred for more light gathering and increased depth of field (e.g. f/2.8 is larger than f/5)
Sensitivity: Refers to ISO. The higher the ISO number the more sensitive the camera is to light so can potentially be useful in low light situations, but higher ISO also means increased noise and poorer picture quality. Noise starts to become apparent after ISO 800.