How to Choose a Digital Camera
1. Budget: First, you need to consider your budget for buying a digital camera. Market prices range from simple cameras costing a few thousand baht (with limited capabilities) to more basic ones starting from around ten thousand baht, increasing in specifications and quality up to hundreds of thousands of baht. Once you've set a budget, say twenty thousand baht, focus only on cameras within your budget. Don't bother considering higher-priced models.
2. Image Sensor: Specifications usually mention "Image sensor" or "Image recording." Simply put, it's the device that captures images instead of film. Some brands use CMOS, but most, if not all, use CCD, varying in size. Larger CCDs generally capture more detail but are more expensive. Check the specifications for CCD size, such as 1/1.8 inch, 1/2.7 inch, or 2/3 inch (measured diagonally).
3. Color Depth (Bit Depth): The greater the color depth, the more detail it captures. The color depth of a camera is better, such as 10 bits/color or 12 bits/color. This means that natural colors have three colors, RGB. If one color can display 13 bits, three colors will display 36 bits, and so on. High-end cameras may be able to achieve up to 16 bits/color or 48 bits at RGB, which is equivalent to good quality slide film. However, it's unclear why only some camera brands and models disclose their color depth. Especially low-spec cameras, such as those with only 8 bits/color (which is actually quite a lot, as it would be 24 bits at RGB, displaying 16.7 million shades of color), are rarely mentioned. Professional cameras, however, usually show the numbers clearly, demonstrating their superior color depth. A low color depth results in poor color separation. For example, dark red, medium red, and light red flower petals appear to have good shading to the naked eye, but when photographed, they appear as a single red color. Using slide film would give a closer look to what the eye sees (professional slides perform better).
4. When buying a digital camera, look at the Effective resolution. We often hear people say, "This one has 3 million pixels," or "This one has 4 million pixels," but most of the time, this refers to the image sensor resolution. The actual image size will be lower. Check the specifications in the manual or brochure and look for the word "Effective," which is the actual image size you will get. For example, the brochure might say 5.24 million pixels, but the specifications clearly state that the maximum image size you can get is 2560 x 1920 pixels. If you multiply that, you get 4.9 million pixels.
5. Interpolate: In some camera models, if you look at the image size according to the specifications, you might be surprised because when you multiply it, you get a higher resolution than expected. For example, a 3 million pixel CCD might produce an image size of 6 million pixels. This is because certain technologies are used to increase the resolution. Examples include Fuji's Super CCD or EPSON's HyPict. However, the quality won't be as good as the true resolution of the CCD, but it will be better than cameras with the same Effective resolution. Nevertheless, it's considered an improvement in quality using technology, unlike increasing the resolution of an image using software like Adobe Photoshop, which will significantly degrade the quality when increasing the resolution by a factor of one. This method is often called interpolation, and cameras with this function... There will be a menu to choose whether to use it or not.
6. Resizing Images: While a high-resolution camera is great, don't forget that the resulting file sizes will be very large and consume a lot of memory on the card. If you use a small card, such as 16 MB, with a 3-megapixel camera, it will fill up after only a few pictures. You need a high-capacity card. Sometimes we only need to save reminders, send emails, or use images for websites, which requires reducing the resolution using Photoshop or other programs to 640 x 480 pixels or smaller. However, most digital cameras allow you to choose from several image sizes to suit the intended use. For example, the Olympus E-20 offers 5 image size options, the smallest being 640 x 480 pixels.
7. Response Time: Almost all digital cameras don't specify this in their specifications, except for high-end compact cameras or digital SLRs, where it's considered a key feature and highlighted in the brochure. Some models respond as soon as the camera is switched on, ready to take a picture in less than half a second. It's almost indistinguishable from a 35mm film autofocus camera, making it hard to tell whether you're using a digital or film camera. However, this technology is improving steadily. In the future, even inexpensive digital cameras will have responsiveness as fast as high-end, expensive cameras.
8. More Buffer, More Better. A large buffer, or built-in memory, allows for continuous and fast shooting. After pressing the shutter, the image data, after processing, is temporarily stored in the buffer before being saved to the memory card (a green or red light usually flashes to indicate this). This allows you to take the next picture immediately without waiting for the saving to finish. A large buffer allows for faster and more continuous shooting. For example, if the camera specifications state continuous shooting at 3 frames per second, and you can take 10 pictures in a row, it means that after 10 pictures, you can't press the shutter again because the buffer is full. You have to wait for the images to be saved to the card. Once there's enough space, you can take more pictures without waiting for all 10 images to be saved to the card. A large buffer also allows you to easily view and zoom in on existing images after pressing the shutter. You can save or delete images instantly, with virtually no waiting time.
9. RAW File Format: High-end, high-resolution cameras offer a RAW format in addition to JPEG or TIFF. This is because the RAW format stores color depth better, such as in Nikon's digital SLRs.