H4x3r
AKA ComatoseClown
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Here are some frequently asked questions. If you have suggestions or want to add to the list just PM myself or Hikaricloud
Terminology:
Aperture
The aperture is the hole inside the lens that allows light through. Aperture is measured in “f†numbers - a ratio of the diameter of the hole and the focal length of the lens. The size of this hole can be adjusted – a larger hole allows more light in, a smaller hole less. An important effect of this is the depth of field. A smaller hole (higher “f†number) produces a lot of depth of field. The reverse happens with a larger hole (smaller “f†number). In digital photography, DSLRs can produce a range of depth of field effects. Compact digital cameras can't. This is due to the smaller sensors and shorter focal lengths used.
Compact Flash (CF) memory card
A popular type of memory card. Used in digital photography to store images. The amount of memory per card varies. Popular memory capacities range from 256mb to 8GB. The larger capacity cards are really of use to professionals only. CF cards are the largest popular format memory card. These days they are used mostly in larger digital cameras.
CCD
Stands for Charge-Coupled Device. A type of sensor commonly found in consumer level (i.e. affordable!) cameras. See sensor for more information.
Depth of field
Depth of field is a measure of how much of a scene (from the front to the back of the image) will be in focus. Although not strictly digital photography terminology, the affect still applies to digital cameras. In landscape photography it's common to want everything in focus, from the rocks in the foreground to the hills in the distance ("deep" depth of field). For portrait photography it's usually best to have a shallow depth of field (i.e. keep only part of the image in focus). This allows the subject to be in clear focus, but makes the background blurred. (see also aperture)
Diffuser
A piece of opaque plastic that sits over the top of a flashgun. It's job is to soften the light from the flashgun, and therefore reduces harsh shadows caused by a 'bare' flash.
ISO
ISO is a term "borrowed" from film photography. In film photography the ISO was a measure of how sensitive film was to light. It was called film speed. The higher the number, the more sensitive it was (and the film was called "fast film"). E.g. ISO 100 was not that sensitive, ISO 1600 was very sensitive. In digital photography the number (still called "ISO") refers to how sensitive the image sensor is to light. By making the sensor more sensitive to light, photos can be shot with higher shutter speeds and/or in lower light. The downside of making the image sensor more sensitive is that it introduces noise into the picture. Noise is the digital equivalent of film grain.
JPEG
In digital photography terminology, JPEG is a type of lossy file format. Stands for Joint Photographic Experts Group. It is the most common file format used in digital photography. When the image is saved, the camera strips out data (parts of the photo) that the human eye probably won't notice. This is called “compressing†the file. It keeps the size of the file down so that more images can be stored on the camera's memory card.
The level of compression is set by the photographer and will affect image quality. The more the image is compressed, the more data is thrown away (and a small file size is the result). Less compression = less data thrown away = larger file size.
The danger is that if a file is compressed too much (i.e. lots of data is thrown away), the quality of the image suffers. The photos look “blocky†and “pixelatedâ€.
On digital cameras the highest quality setting (usually called “Best†or “Fineâ€) results in less data being lost, and a good quality image is produced. The lowest settings (usually called “Low†or “Economyâ€) results in more data being lost, and a poor quality image is produced.
Lenses
Not specifically digital photography terminology, but still relevant to digital cameras, especially DSLRs.
When using a DSLR it is possible to change the lens on the camera.
The job of the lens is to throw a circle of focused light onto the image sensor. In the days of film cameras that meant the light fell onto the film. With digital photography the light hits the image sensor. Image sensors are usually smaller than a 35mm frame of film. This means the circle of focused light can be smaller too. Specific "digital only" lenses will throw a circle of focused light that will cover a digital camera's sensor, but is too small to cover a 35mm frame. They are therefore only suitable for use on digital cameras.
Macro
Not strictly digital photography terminology, "macro" means the ability for a camera (or lens) to focus so near to the subject that it is captured life size on the image sensor.
The term macro is used more loosely these days, and usually refers to the ability to get close up shots (not necessarily life size). Typical macro subjects are flowers and insects.
Memory Card
Essential for digital photography! In digital photography terminology consider a memory card to be “digital film†- traditional cameras record photos onto film, digital cameras save photos onto a memory card.
Memory cards come in different shapes and sizes. You need to use the correct memory card for your digital camera. The most popular formats are CF, Memory Stick, SD and xD.
CF and SD are the most widely used. Consequently they are a little cheaper than the others.
Metadata
When a digital camera captures an image it records two things in the file that is saved - image data itself, and data about that data (confusing, isn't it?). The "about the image" data is called "metadata". The information it contains varies from camera to camera, but typically includes, amongst other things, information such as date, time, shutter speed, aperture, ISO and file type.
This information can be useful when trying to find photos later (because you can search for your images by date), and helps to improve digital photography because the photographer can work out what combinations of shutter speed and aperture work well.
Noise
In digital photography terminology, noise is the digital equivalent of film grain. It shows up on digital photographs as small coloured blotches, usually in the darker areas of an image. Noise often goes overlooked in snapshots, but becomes very obvious if enlargements are made.
Noise is worse in digital photos taken in low light. It can be removed to some extent by software, but a better quality digital camera will usually produce less noise in the first place.
Whereas film grain can add atmosphere to a photograph, digital noise is generally considered to be unattractive. Digital photographers looking for a "grainy" effect aim to start with a clean image (i.e. free from digital noise), and then add the grain effect afterwards using software.
Pixel
A small dot in a digital photography image. Thousands of pixels make up a digital photograph.
Resolution
In digital photography terminology, resolution is a measure of the number of pixels there are on a sensor. The resolution of digital cameras is measured in “megapixels†– millions of pixels. It works by a simple bit of maths – multiply the number of pixels along the bottom of the sensor by those up the side. For example, a sensor with 3000 pixels along the bottom, and 2000 up the side equals 6,000,000 pixels in total. That would make it a 6 megapixel camera.
Theoretically it is possible to change the sensor in a digital camera (say, to upgrade a 5 megapixel sensor to a 10 megapixel sensor). In practice though, so much of the camera would have to be replaced it makes this impossible to do.
Secure Digital (SD) memory card
A popular type of memory card. Used in digital photography to store images. The amount of memory per card varies. Popular memory capacities range from 128mb to 4GB. Some SD cards have a clever feature where part of the card can flip up; this allows the card to be inserted into a USB port on a computer – images can be transferred to the computer without the need for a card reader or any special cables.
Sensor
The electronic chip that records the image in a digital camera. They come in two main types. CCD (Charge-Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor) are the most common. CCDs are used almost exclusively in compact cameras, CMOS sensors are used in larger, and more expensive DSLRs.
There are other types, but not well used. JFET (Junction Field Effect Transistor) – developed by Nikon and used in a very small number of their cameras. X3– a new type of sensor developed by Foveon. Used only in Sigma DSLRs and a couple of Polaroid compact cameras.
Shutter Delay
In digital photography terminology, shutter delay refers to the time between pressing the shutter button to the camera actually taking the picture. It is not a term used in traditional photography because the delay was negligible.
To overcome the problem of shutter delay most digital cameras allow you to pre-focus by pressing the shutter button halfway, and once the focus has been locked the shutter can be pressed fully.
The problem is less apparent with digital SLRs.
Shutter Speed
In digital photography terminology, shutter speed is slightly different to traditional photography. Traditionally, the shutter opened when you pressed the camera's button, exposed the film behind the shutter, and then closed again; covering the film back over in the process.
With electric sensors the "shutter" is controlled by the camera's computer. A short shutter speed means the sensor is charged for a fraction of a second. For longer shutter speeds, the sensor is kept charged for longer.
The shutter noise in most compact digital cameras is created by a small speaker in the camera and mimics a real shutter. It has its use - it lets you know when the photo has been taken.
Digital SLRs have no need to mimic a shutter as they work with a combination of shutter and electrically controlled sensor.
SLR
Stands for Single Lens Reflex. A design of camera where the photographer looks straight through the lens prior to taking a photograph. The view through the viewfinder of a SLR camera is therefore the exact same image that will be recorded by the camera.
from Here
Terminology:
Aperture
The aperture is the hole inside the lens that allows light through. Aperture is measured in “f†numbers - a ratio of the diameter of the hole and the focal length of the lens. The size of this hole can be adjusted – a larger hole allows more light in, a smaller hole less. An important effect of this is the depth of field. A smaller hole (higher “f†number) produces a lot of depth of field. The reverse happens with a larger hole (smaller “f†number). In digital photography, DSLRs can produce a range of depth of field effects. Compact digital cameras can't. This is due to the smaller sensors and shorter focal lengths used.
Compact Flash (CF) memory card
A popular type of memory card. Used in digital photography to store images. The amount of memory per card varies. Popular memory capacities range from 256mb to 8GB. The larger capacity cards are really of use to professionals only. CF cards are the largest popular format memory card. These days they are used mostly in larger digital cameras.
CCD
Stands for Charge-Coupled Device. A type of sensor commonly found in consumer level (i.e. affordable!) cameras. See sensor for more information.
Depth of field
Depth of field is a measure of how much of a scene (from the front to the back of the image) will be in focus. Although not strictly digital photography terminology, the affect still applies to digital cameras. In landscape photography it's common to want everything in focus, from the rocks in the foreground to the hills in the distance ("deep" depth of field). For portrait photography it's usually best to have a shallow depth of field (i.e. keep only part of the image in focus). This allows the subject to be in clear focus, but makes the background blurred. (see also aperture)
Diffuser
A piece of opaque plastic that sits over the top of a flashgun. It's job is to soften the light from the flashgun, and therefore reduces harsh shadows caused by a 'bare' flash.
ISO
ISO is a term "borrowed" from film photography. In film photography the ISO was a measure of how sensitive film was to light. It was called film speed. The higher the number, the more sensitive it was (and the film was called "fast film"). E.g. ISO 100 was not that sensitive, ISO 1600 was very sensitive. In digital photography the number (still called "ISO") refers to how sensitive the image sensor is to light. By making the sensor more sensitive to light, photos can be shot with higher shutter speeds and/or in lower light. The downside of making the image sensor more sensitive is that it introduces noise into the picture. Noise is the digital equivalent of film grain.
JPEG
In digital photography terminology, JPEG is a type of lossy file format. Stands for Joint Photographic Experts Group. It is the most common file format used in digital photography. When the image is saved, the camera strips out data (parts of the photo) that the human eye probably won't notice. This is called “compressing†the file. It keeps the size of the file down so that more images can be stored on the camera's memory card.
The level of compression is set by the photographer and will affect image quality. The more the image is compressed, the more data is thrown away (and a small file size is the result). Less compression = less data thrown away = larger file size.
The danger is that if a file is compressed too much (i.e. lots of data is thrown away), the quality of the image suffers. The photos look “blocky†and “pixelatedâ€.
On digital cameras the highest quality setting (usually called “Best†or “Fineâ€) results in less data being lost, and a good quality image is produced. The lowest settings (usually called “Low†or “Economyâ€) results in more data being lost, and a poor quality image is produced.
Lenses
Not specifically digital photography terminology, but still relevant to digital cameras, especially DSLRs.
When using a DSLR it is possible to change the lens on the camera.
The job of the lens is to throw a circle of focused light onto the image sensor. In the days of film cameras that meant the light fell onto the film. With digital photography the light hits the image sensor. Image sensors are usually smaller than a 35mm frame of film. This means the circle of focused light can be smaller too. Specific "digital only" lenses will throw a circle of focused light that will cover a digital camera's sensor, but is too small to cover a 35mm frame. They are therefore only suitable for use on digital cameras.
Macro
Not strictly digital photography terminology, "macro" means the ability for a camera (or lens) to focus so near to the subject that it is captured life size on the image sensor.
The term macro is used more loosely these days, and usually refers to the ability to get close up shots (not necessarily life size). Typical macro subjects are flowers and insects.
Memory Card
Essential for digital photography! In digital photography terminology consider a memory card to be “digital film†- traditional cameras record photos onto film, digital cameras save photos onto a memory card.
Memory cards come in different shapes and sizes. You need to use the correct memory card for your digital camera. The most popular formats are CF, Memory Stick, SD and xD.
CF and SD are the most widely used. Consequently they are a little cheaper than the others.
Metadata
When a digital camera captures an image it records two things in the file that is saved - image data itself, and data about that data (confusing, isn't it?). The "about the image" data is called "metadata". The information it contains varies from camera to camera, but typically includes, amongst other things, information such as date, time, shutter speed, aperture, ISO and file type.
This information can be useful when trying to find photos later (because you can search for your images by date), and helps to improve digital photography because the photographer can work out what combinations of shutter speed and aperture work well.
Noise
In digital photography terminology, noise is the digital equivalent of film grain. It shows up on digital photographs as small coloured blotches, usually in the darker areas of an image. Noise often goes overlooked in snapshots, but becomes very obvious if enlargements are made.
Noise is worse in digital photos taken in low light. It can be removed to some extent by software, but a better quality digital camera will usually produce less noise in the first place.
Whereas film grain can add atmosphere to a photograph, digital noise is generally considered to be unattractive. Digital photographers looking for a "grainy" effect aim to start with a clean image (i.e. free from digital noise), and then add the grain effect afterwards using software.
Pixel
A small dot in a digital photography image. Thousands of pixels make up a digital photograph.
Resolution
In digital photography terminology, resolution is a measure of the number of pixels there are on a sensor. The resolution of digital cameras is measured in “megapixels†– millions of pixels. It works by a simple bit of maths – multiply the number of pixels along the bottom of the sensor by those up the side. For example, a sensor with 3000 pixels along the bottom, and 2000 up the side equals 6,000,000 pixels in total. That would make it a 6 megapixel camera.
Theoretically it is possible to change the sensor in a digital camera (say, to upgrade a 5 megapixel sensor to a 10 megapixel sensor). In practice though, so much of the camera would have to be replaced it makes this impossible to do.
Secure Digital (SD) memory card
A popular type of memory card. Used in digital photography to store images. The amount of memory per card varies. Popular memory capacities range from 128mb to 4GB. Some SD cards have a clever feature where part of the card can flip up; this allows the card to be inserted into a USB port on a computer – images can be transferred to the computer without the need for a card reader or any special cables.
Sensor
The electronic chip that records the image in a digital camera. They come in two main types. CCD (Charge-Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor) are the most common. CCDs are used almost exclusively in compact cameras, CMOS sensors are used in larger, and more expensive DSLRs.
There are other types, but not well used. JFET (Junction Field Effect Transistor) – developed by Nikon and used in a very small number of their cameras. X3– a new type of sensor developed by Foveon. Used only in Sigma DSLRs and a couple of Polaroid compact cameras.
Shutter Delay
In digital photography terminology, shutter delay refers to the time between pressing the shutter button to the camera actually taking the picture. It is not a term used in traditional photography because the delay was negligible.
To overcome the problem of shutter delay most digital cameras allow you to pre-focus by pressing the shutter button halfway, and once the focus has been locked the shutter can be pressed fully.
The problem is less apparent with digital SLRs.
Shutter Speed
In digital photography terminology, shutter speed is slightly different to traditional photography. Traditionally, the shutter opened when you pressed the camera's button, exposed the film behind the shutter, and then closed again; covering the film back over in the process.
With electric sensors the "shutter" is controlled by the camera's computer. A short shutter speed means the sensor is charged for a fraction of a second. For longer shutter speeds, the sensor is kept charged for longer.
The shutter noise in most compact digital cameras is created by a small speaker in the camera and mimics a real shutter. It has its use - it lets you know when the photo has been taken.
Digital SLRs have no need to mimic a shutter as they work with a combination of shutter and electrically controlled sensor.
SLR
Stands for Single Lens Reflex. A design of camera where the photographer looks straight through the lens prior to taking a photograph. The view through the viewfinder of a SLR camera is therefore the exact same image that will be recorded by the camera.
from Here
