A few things to consider when buying a digital camera
This article is intended as a synopsis of desirable features to have on a digital camera, things that should be considered when selecting a camera.
We have purposefully left out some items for consideration: the ergonomic design of a camera; the type of viewfinder; the size and resolution of the LCD monitor; etc. Instead, we have tried to distill those things we judged to be the most important elements.
This article is intended as a synopsis of desirable features to have on a digital camera, things that should be considered when selecting a camera.
We have purposefully left out some items for consideration: the ergonomic design of a camera; the type of viewfinder; the size and resolution of the LCD monitor; etc. Instead, we have tried to distill those things we judged to be the most important elements.
Resolution: As of this writing, and excluding special application cameras, digital cameras are available with sensors that cover a range from 640 x 480 (307,200 pixels) up to 14 megapixel (14 million pixels). For most consumers though, the current economic limit is at 8 megapixel. A word of caution when considering resolution, the true resolution of the sensor is what matters, meaning the number of pixels physically present on the sensor, and not the resolution of the image. If the image the camera produces is bigger than the number of pixels on the sensor, for instance the CCD is 3 megapixel but the image size is 6 megapixel, the image is interpolated. |
| Strictly speaking, the higher the resolution the greater the detail the camera is able to capture, meaning that an 8 megapixel image will always have more detail than a 1 megapixel image. Likewise, larger resolution images result in more detailed prints, and if desired, larger prints. But, when the gap in resolution is not as large, such as is the case between 3.2 megapixel and 4 megapixel, other factors can tip the balance towards a camera with a lower resolution, and its photos may end up being more detailed than those of the higher resolution model. |  |
| One of the factors that can impact the amount of detail a camera captures is compression. (Related articles: Why resolution matters; Resolution vs Image sharpness; Interpolation;How many megapixel do you need?) |
Compression and image formats: One of most important things to look for when purchasing a camera is the type and variety of image file formats it offers. The vast majority of images captured with digital cameras are stored in JPEG format. JPEG uses a lossy compression algorithm that reduces the colour hues of the image in order to reduce its file size therby lessening the time it takes to save it, and the space it takes up on the memory card. |
| The downside of the JPEG format is that if the compression applied to the image is too strong, the quality degrades visibly, and images become much less detailed than they should be. It is therefore critical to ensure that any camera offer a good selection of compression settings. A camera should offer at least 3 image compression settings, and one of these should offer a limited compression, creating files that are no less than 1/4 to 1/6 the uncompressed file size. |  |
| If possible, an uncompressed format should also be available (TIFF) and/or a RAW format that simply stores the image captured by the sensor "as-is". (Related article: Compression) |
Lens: Most compact digital cameras have an optical zoom lens — not to be confused with a digital zoom (see "Related articles below) — and zoom lenses should meet some basic minimums. A lens should have a fairly bright maximum aperture — f2 or f2.8 — and should correct for distortion: barrel distortion at the wide angle end, pincushion distortion at the telephoto end and chromatic aberration. |
| If a long telephoto lens is under consideration, the maximum aperture available at the telephoto end should be checked. Lenses that have relatively small apertures at the maximum telephoto position may require a lot of ambient light to avoid camera shake. Alternatively, it may be advisable to look to a camera that offers a stabilized lens. Additionally, very long telephoto lens tend to produce a better image contrast when LD (Low Dispersion) glass is used in their construction. |  |
Shutter speed range and noise reduction: The shutter speed range of the camera should be checked. Cameras that have the combination of bright lenses and high shutter speed are better at stopping fast action. Similarly, cameras that are capable of long exposure times — at least 8 seconds — are able to capture photos at night. Ideally, the shutter speed range of the camera should extend to both fast and slow shutter speeds. Moreover, a camera able to capture long exposures should offer a noise reduction feature. (Related articles: The effect of shutter speed on the image; Night Photography; Noise: what it is and when to expect it) |
Shooting modes: The availability of a good range of shooting modes is an important element of a camera. Users that want point and shoot simplicity should also look for cameras that provide a variety of Scene modes. Scene modes automatically set a number of shooting parameters for specific types of image types. While not all these modes are useful, a handful of basic scene modes can be very useful:
|
| For users that want the flexibility to experiment with the way the camera captures images, the more "hands-on" Aperture Priority, Shutter Priority and Manual modes should be available. Moreover, the ease of use of the modes — the way shutter speeds or apertures are adjusted — should be checked. Burst (also called Sequential) shooting modes should also be part of the package. These modes are designed to capture a series of images quickly so as to overcome the shutter lag of the camera. While many cameras nowadays exhibit very little shutter lag, autofocus and metering still require a bit of time. Burst modes go a long to overcoming this by allowing the photographer to capture as the action unfolds. From http://www.megapixel.net/html/articles/article-what.php 27/08/2011 |
| Shooting modes: The availability of a good range of shooting modes is an important element of a camera. Users that want point and shoot simplicity should also look for cameras that provide a variety of Scene modes. Scene modes automatically set a number of shooting parameters for specific types of image types. While not all these modes are useful, a handful of basic scene modes can be very useful:
|
| For users that want the flexibility to experiment with the way the camera captures images, the more "hands-on" Aperture Priority, Shutter Priority and Manual modes should be available. Moreover, the ease of use of the modes — the way shutter speeds or apertures are adjusted — should be checked. Burst (also called Sequential) shooting modes should also be part of the package. These modes are designed to capture a series of images quickly so as to overcome the shutter lag of the camera. While many cameras nowadays exhibit very little shutter lag, autofocus and metering still require a bit of time. Burst modes go a long to overcoming this by allowing the photographer to capture as the action unfolds. |
No comments:
Post a Comment