|
Basic Camera Settings
A digital camera will have many different settings that are accessed either through a menu system or using dedicated buttons on the camera. Many of the more advanced options will be covered in the next section, however there are a few that really need to be understood from the start if you don't want to miss out on some great shots.
Quality / Resolution
|
Most cameras will have a range of different resolution and quality settings. Resolution is often expressed as a megapixel rating or words like large, medium and small. If you buy an eight megapixel camera, this refers to the highest number of pixels an image can have. You may well have the option to select lower resolutions which might be labelled as '5MP', '3MP' or '1MP'. The lower resolutions create images that take a lot less memory on the card, therefore as soon as you switch you should see an increase in the number of pictures that can be written to the memory card.
Another factor that can often be changed is the image quality (this may be called compression). This is usually referred to using adjectives such as 'fine' and 'normal'. It refers to the amount of image compression that will be applied before the picture is stored. On the small LCD screen, you will not notice the difference between the different quality modes, but if you come to edit the pictures later, the lower quality (higher compression) images can cause major problems. |
Picture resolution, quality settings from a Lumix camera
|
Our advice it to always use the highest resolution and quality. Memory cards have become very cheap so don't get caught out. If you do find yourself running out of space on the memory card first go through the pictures you've taken and delete those that you are not likely to want rather than switching down the resolution or quality.
If you shoot in low resolution/quality you may end up with a masterpiece that can't be printed any bigger than a 6x4" print.
File Format
All digital cameras store images in JPEG format (sometimes written JPG). This is a standard and very common format, specifically designed for storing photographic images (that's what the 'P' stands for). Its big advantage is that it can compress the amount of data that needs storing by 80-90% (a 10 megapixel image contains 30MB of data however a JPEG image will typically be about 4MB in size).
To achieve this, it reduces the quality of the image. Many cameras have two or three different levels of compression you can select - a 'high quality' or 'fine' mode that creates fairly large files but keeps image quality to a maximum, and a 'normal' quality mode that compresses the images more (usually around 90-93% compression) allowing you to get more pictures on you memory card but at the expense of picture quality.
To professionals and serious amateurs, any form of degradation to the image is completely unacceptable. Therefore all DSLRs and some bridge/high-end compacts offer the option to store images in RAW format. Think of RAW files as a digital negative holding everything that was captured by your camera. (See later section for a more comprehensive look at RAW files.)
So which should you use? JPEGs are a universal format that can be loaded into most image software on your PC without conversion, the files are smaller than RAW, and you can take them to any high street developer who accepts digital memory cards and get them printed. But ultimately, if your camera supports RAW, then you should aim to use this - it is higher quality and gives you greater flexibility to manipulate the images later.
For more information on JPEG, RAW and other image formats, see sections:
The Digital Domain - More about file formats
The Digital Domain - Shooting in RAW format
ISO
ISO is a way of adjusting the sensor to make it more sensitive to light. In the pre-digital camera days, a roll of film had a fixed ISO setting however, with a modern imaging sensor you can adjust it by increasing the gain on the sensor amplifier. The down side is that you also increase the amount of noise in the image.
A general guide is to shoot with the lowest ISO setting possible for the lighting conditions (ideally ISO 100 or 200) and only increase the ISO if the shutter speed starts to get so slow that camera shake becomes visible.
Noise can be especially problematic on compact cameras that use much smaller image sensors. If you increase the ISO beyond about ISO 400 (on a compact), the image processing inside the camera usually has to smooth over fine detail in an attempt to bring down the amount a noise (a technique called noise reduction). The reason is that the size of the pixels becomes so tiny on a small sensor that it is not able to gather sufficient light in the fraction of a second that the shutter is open.
To give an idea of just how small these pixels can be, the table below shows the number of photosites (pixels) per square millimetre on some different sized sensors:
| Camera Model |
px/sq.mm |
Type of camera |
| Nikon D3 |
13,900 |
Pro 12.1 MP DSLR Full Frame Sensor |
| Canon EOS 40D, 400D |
30,600 |
Consumer level DSLR |
| Typical compact |
296,000 |
An 8 MP compact with a 1/2.5" sensor |
Although a lower number of pixels per millimetre generally means lower noise levels, advances in sensor technology means that it is not the only factor. For example, Canon claims that when they upgraded the 350D (8MP camera) to the 400D (10MP camera), they were able to maintain the quality and low noise levels due to newer advances in sensor technology.
To emphasize the importance of sensor size to image quality and noise levels, we have two pictures (both cropped from a much larger image shown right) taken on two cameras: one an entry level DSLR and the other a top selling compact camera. You can clearly see how the tiny sensor on the compact suffers from high levels of noise which, for many people, makes having such a high ISO setting pointless.
|
|
|
|
The two images above are cropped from a larger image shown on the right. Both pictures were taken at ISO 1600.
Top left: Nikon D40 (an entry level DSLR)
Top right: a top selling compact camera
Images courtesy of www.imaging-resource.com. This is a really good website for camera reviews. |
|
Optical and Digital Zoom
The zoom range of a lens is usually given as the minimum and maximum focal length. This can either be the actual focal length (lenses for DSLRs) or the focal length that a 35mm film camera would need to give the same level of magnification. The physical size of the sensor affects the magnification, so by quoting the 35mm equivalent, you can compare like with like across cameras with different sized sensors.
Smaller focal lengths mean a wider angle of view. For example a 28mm (35mm equiv) has a diagonal angle of view of 76° but a 105mm focal length has an angle of 23°.
If your camera has a digital zoom, please ignore it. Better still, forget it even exists (some cameras allow you to disable it in the menus). Here is why (all three images are scaled down for display on this web page):
|
|
Non-zoomed image. |
 |
With optical zoom, the camera is able to capture increased detail from the areas you have zoomed in on. |
 |
With a digital zoom, there is no additional detail in the image as it is derived mathematically from the original non-zoomed image.
It achieves this by using a mathematical technique called interpolation to try to estimate the additional detail.
As you can see, the picture is considerably more blocky than the optical zoom. |
If you really must zoom beyond the limit of your optical zoom, just take the picture at the maximum optical zoom and crop down to the actual area you require later. You can then, if required, increase the pixel resolution using a method called resampling (which is all the camera is doing with digital zoom but under your complete control).
In software you can create a 200x digital zoom if you wish - just expect little difference in pictures of the Leaning Tower of Pisa and a Pepperoni Pizza!
|
Photographs
This is a site about photography so I'm sure you are expecting to see plenty of pictures.
For now, why not take a peek at the flickr galleries belonging to the two authors of this site.
Colin's Flickr Page
Phil's Flickr Page
"If you saw a man drowning and you could either save him or photograph the event ... what focal length and aperture would you use?" - Anonymous
|
