How to choose the digital camera to suit your needs?
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| In today's market, there are many different types of digital cameras to suit your different needs.
We hereby list some considerable factors for choosing a digital camera.
Due to the different purpose of using digital camera, it is difficult to have a camera which is perfect to everyone.
Therefore it is recommended to choose the camera to suit your own needs. |
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| Image Resolution
| The resolution of the digital camera will effect the image size directly.
Usually, the unit is "mega pixel". Generally saying, pixel size represents the level of detail of the image. Millions of dots vertically and horizontally form a digital photo.
Pixel:
- 1.3 mega pixel is suitable for screen viewing, 1280x960 is well enough for screen of 17 to 21 inches.
- 2 mega pixel can achieve print out under 4x6 inches. The detail of such photo can be compared with photo taken by traditional cameras.
- 3 mega pixel and above will make computer editing move convenient. You can do whatever you like with the image taken.
- 4 mega pixel and above can be used to print larger photos – 6x8 inches or print out with finer detail.
- Most major digital camera manufacturers have already stepped into 5 mega pixel. It is believe it will become the mainstream very soon.
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| The pixel size of the digital camera will decide the resolution of a photo to be enlarged.
However, the output file will be larger. Which means, more storage space will be needed for your photos.
And it will also take longer time for image display, transmission or process. But be noted that resolution is not the only factor of the camera performance.
The quality is not only decided by resolution but also the quality of the picture. High resolution not necessarily means good picture quality. |
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| Image resolution |
| When you are buying a digital camera, you should not judge the quality from only the LCD screen on the camera, but also to understand the printout quality.
It is better to ask for a image that taken by the camera, including image displayed on the screen and printed out.
Usually the display on the screen is the most referable. Print out quality will be depended on the nature of different printer. |
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| Lens |
| Apart from CCD, Lens affects the photo quality most.
Generally, the resolution in the middle of the lens is highest; the resolution decreases gradually from the middle to the edge.
This is why the skirt area of a photo may be less clear, less bright, and easier to be distorted.
The digital photo quality is also affected by the characteristic of the lens.
This distortion is not easy to be quantified in User Manual; therefore, photo samples are used to illustrate different distortions.
When choosing your camera, you can visit official websites of camera manufacturers where they usually
offer photo testing samples for your buying references. |
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| Battery and Power Consumption |
If you treasure your battery life, you can turn off LCD display on your digital camera.
One of the most power-consumed parts in a camera is LCD display.
In order to obtain clear display, LCD background illumination consumes power heavily (You can turn off the LCD display to save the power).
For general Alkaline Battery or Ni-CD/Ni-MH battery, the power can last for around an hour (with LCD on) whereas for camera Lithium battery, it can last longer.
In addition to LCD display, CCD (Charge Coupled Devices) also consumed lot of power.
For those models that use LCD display as view finders, in order to drive CCD continuously, the power loading is heavy.
Sometimes, the power of four dry batteries can only last for less than 30 minutes.
Therefore, take a check of whether rechargeable batteries or charger are included in your camera package or whether other relevant charging information is mentioned. |
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| Storage Device |
We used to use film as storage media for traditional photography.
For digital photography, memory card takes off this job to be the photo file storage device.
It is important in terms of its close relationship with digital camera.
You literally only need to pull out the memory card and bring it to photo printer or digital minilab, and photos can be
printed out directly. Therefore, you need to pay much attention when choosing the memory card.
Generally, there are six kinds of memory cards in the market:
CF (Compact Flash), SM (Smart Media), MMC (Multi Media Card), SD (Secure Digital Card), xD (xD-Picture) and MS (Memory Stick, developed by SONY). |
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| CF (Compact Flash) |
CF (Compact Flash): The earliest standard of formatted mobile memory and also the most used storage device. General specification is 42.8mm x 36.4mm x 3.3mm. Characteristics of CF card are cheap, large storage space, fast speed, and card reader compatible. |
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| SM (Smart Media) |
SM (Smart Media): One of the "lightest" memory cards, weights only 1.8 gram, size: 45mm x 37mm x 0.76mm. Compared with CF card, it provides write protection function (similar to the write protection device of a 3.5" disk) which helps to prevent unexpected deleting files. It is also compatible with card reader. However, due to the limitation of storage space (128 MB limits), the company who promotes the SM is getting to abandon the development of SM card. |
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| MMC (Multi Media Card) |
MMC (Multi Media Card): It is the one of the smallest removable Flash memory cards. It weights less than 2gram with high storage capacity, low power consumption and high durability. |
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| SD (Secure Digital Card) |
SD (Secure Digital Card): The ancestor of SD card is MMC memory card. With the size of a stamp and the weight of 1.5gram, the card can transfer data at speed of 10MB per second, which enables quick and convenient file copying and downloading/uploading.
It also provides the switch of write protection preventing from unexpected deleting. It is also shake-proof and adapted to various environment conditions. |
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| xD (xD-Picture) |
xD (xD-Picture): Developed by both Olympus and Fujifilm, the xD card is claimed to be the smallest card: 20mm x 25mm x 1.7 mm, 3 gram with 8GB storage capacity. It can store music, photo and video and prevent from illegal copying with its ID protection device; however, it is not equipped with write protection function. The bottleneck of xD card development at present is that only few numbers of cameras are compatible with the xD card and the specification is not yet popularized. |
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| MS (Memory Stick) |
MS (Memory Stick): The MS card is developed by SONY and mainly for SONY's products. The size of the card is 50mm x 21.5mm x 0.28mm with 4 gram weight. It is developed based on the advantages of CF and SM cards. MS card also equipped with a user-friendly write protection device. |
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| Please be advised, it would be risk-free to bring more than just one memory card with you when traveling. There are companies who run memory card leasing business. Just for the information. |
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| Accessories
| When you are comparing the prices of camera packages, be noted to identify what accessories are included.
Some camera packages include many accessories, some don't. Generally, carrying bag and cables are included inside the package.
You have to be careful when choosing the camera since some cameras are cheap but they are with less accessories than other choices.
Basically, elemental accessories are battery, memory card, flash light and image outputting cable. |
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| User interface
| | There are still more other factors needed to be considered when choosing the camera.
Whether it is easy-handling and whether the appearance, the user interface, and the material are favored by you. |
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| ISO
| ISO number in film indicates the sensitivity of film to the light.
The ISO number are normally between 100 to 800. The higher the ISO number is, the higher the sensitivity is.
The popular ISO 100 film is better used in full light environment where higher ISO numbers are better used in dim light environment and moving objects.
In digital camera, ISO number indicates the exposure standard of its metering system (similar to the ISO number for traditional film).
The lower the ISO number is, the less exposure it needs and the more refined the photo quality is, and vice versa.
The light may be insufficient in night/indoor photo shooting, therefore, you may select different ISO number according to the environment. |
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| Keep above points in mind and evaluate the size, functionality and characteristics of your camera candidates, you will be able to find your ideal digital camera. |
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| *Terminology: |
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| CCD and CMOS |
CCD and CMOS are image sensors to convert light into electrons in a digital camera.
Basically, differences between the two sensors are as follows:
- CCD sensors create high-quality, low-noise images. CMOS sensors, traditionally, are more susceptible to noise.
- Because each pixel on a CMOS sensor has several transistors located next to it, the light sensitivity of a CMOS chip tends to be lower.
Many of the photons hitting the chip hit the transistors instead of the photodiode.
- CMOS traditionally consumes little power. Implementing a sensor in CMOS yields a low-power sensor.
- CCDs use a process that consumes lots of power. CCDs consume as much as 100 times more power than an equivalent CMOS sensor.
- CMOS chips can be fabricated on just about any standard silicon production line, so they tend to be extremely inexpensive compared to CCD sensors.
- CCD sensors have been mass produced for a longer period of time, so they are more mature. They tend to have higher quality and more pixels.
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| Digital Zoom & Optical Zoom |
Optical zoom is similar to what you'll find in a regular 35mm camera:
When you push the button to zoom in or out, physical lens elements move inside the camera, to achieve the desired effect.
Digital zoom, on the other hand, has no moving parts. Using the "electronic brain" within the camera instead, the camera takes a look at what it's "looking at", and
digitally zooms in, usually two or three times closer.
The problem with digital zoom is that you lose quality when you do this -- your images will tend to be more "pixelated" than the same image taken with an optical zoom camera.
This is due to the "interpolation" the camera uses, which is a nice way of saying that it makes a guess about how the picture should look while zoomed in. |
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| File Save Format |
| RAW File Characteristics - |
RAW file retrieves the image from the original data in the image storage device, without any adjustment in the color compensation, color balance, GAMMA, and etc.
Unlike the JPEG file, RAW file is non-transformed and non-compressed file format.
For the image quality demand, RAW/TIFF files are better than JPEG files.
The fact of smaller file size of RAW (as compares to TIFF) has the following two advantages:
1.Save memory space.
2.Accelerate photo-taking efficiency.
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| TIFF (Tagged Image File Format) File Characteristics - |
| TIFF is a non-transformed file format, which usually has larger file size than JPEG/RAW.
Special software is required to open RAW files, while TIFF files can be opened by most common image display software.
The thumbnail file of TIFF can store the image resolution.
Due to the high compatibility of the TIFF, multi-images (e.g. small preview image icons) are also allowed to be stored;
therefore, TIFF files are usually applied within graphic and layout design software tools. |
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| JPEG File Characteristics - |
JPG/JPEG uses the transformed compressed format to save image files, which reduces the color and gray tone level while under compressing. We normally notice the color processing of JPEG images; however, actually the gray tone of the image is also being processed normally.
The compressed file size of JPEG compares to that of non-transformed image file is only 1/10 or less. Normally, JPEG use the technique of transforming the color dot space into frequency principle.
As human eyes are less sensitive to high frequency, this method can be used to greatly compress the image data into rougher image data reducing the file size accordingly.
The JPEG file created by the digital camera will automatically generate a thumbnail file, which includes the Meta information that we are familiar with for the EXIF information.
The newest standard is EXIF 2.2 (EXIF Print), which contains more complete image and color information about the photo taken.
Beside as reference for photo taker, EXIF 2.2 also provides more consistent color uniformity while printing, especially for camera to printer direct printing.
The file size for JPEG file containing EXIF information is always a little larger, around 2KB~6KB more.
While under the image processing, if you really concern about the file size of the image, you can delete the EXIF information. |
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| What White Balance |
| The so called "White Balance" is to alter the RGB original colors to get more accurate true colors.
The digital cameras are very smart nowadays, as most of them carry automatic "White Balance" function.
However, it does not necessary alter the colors that match your preference.
So, if your color preference is close to the color of film, you can adjust the setting to "sunlight" mode.
Of course, you can try more different settings for your preference. |
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