All digital cameras from reputable manufactures on the market today will take good pictures. What separates cameras, of similar cost and features, is the software built into the camera and how aggressively the camera maker decides to process the image. A bright, colorful, snappy image might be just right for the "let Kodak do the rest" crowd. But not what the "I would rather to do it myself" people want.
Digital cameras are in a very early stage of evolution. They will continue to improve and costs will decline. The selection is staggering with new models appearing in rapid sequence. The market place is starting to shake out, companies are beginning to consolidate or finding the market unprofitable and are dropping out.
Buying a film camera is relative simple. They have been around for a hundred years and have settled into a fairly narrow set of standard features. Not so with digital cameras. These electronic wonders seem to have no limits in design and features.
Before buying a camera it is always wise to define the primary use you will put it to. Cameras are still relatively expensive and some research will pay dividends and make you happier with your decision.
Film cameras have a size limitation because of the need to put a roll of film in them. This is not the case with digital cameras. They range from credit card size to full blown professional SLR's. Larger format cameras are beginning to appear on the market. Practically, cameras like computer keyboards can be to small to use efficiently. At the other end, professional cameras can be too large and heavy for casual use. You must find what is best for your situation. The only way to accomplish this is to physically handle the camera you are interested in. Ergonomics is a big factor in whether or not you enjoy getting your camera out and using it.
Lenses
Lenses come in two varieties, fixed focal length and zoom. The fixed focal length type of point and shoot cameras tend toward the moderately wide angle region. Zoom lenses will range from about 3x to 12x. Most people can not hold a lens of more then 200 mm (35 mm equivalent) steady. Cameras are beginning to employ image stabilization systems as a result. CCD image sensors are relatively slow when compared to film. Especially the small CCD's used in less expensive cameras. Generally around 50 to 80 ISO. If the ISO value is raised (increasing the electronic gain of the CCD) image noise can become a problem for those who like to make large prints.
Practically speaking it is not an issue for those who make album or moderately sized pictures. Because of this noise issue, it is desirable to have a lens that will have a large aperture and gather as much light as possible. At the present time f/2.8 lenses are the most prevalent. When zoom lenses are extended to longer focal lengths, the largest aperture diminishes. Usually to about f/4.8 (1.5 f/stops). Smaller apertures mean longer shutter speeds, which compounds the problem of holding the camera steady.
Lenses from most camera manufactures today are of good quality. Sharpness is generally not a problem. What appears to be softness in the image from some cameras, is usually due to in camera processing when the image is saved to a memory card. This can be corrected in the digital darkroom.
The digital zoom in most cameras today is a feature that should be avoided if there is an alternative. The image is degraded considerably and is better handled in the digital darkroom with the crop tool or the image size command.
How Digital Cameras are Classified
Cameras are designated by the number of picture elements (pixels) in the image sensor. The number of elements horizontally and vertically are multiplied to give a total number which is called Megapixels. Therefore an image sensor with 1600 x 1200 pixels would be called a 2 megapixel camera. (1600x1200 = 1,920,000) The numbers are rounded to the nearest million or tenth of a million. Rounding up is the preferred method by the camera makers.
How many pixels per inch are required to make a good print
This is a personal thing, my testing shows that 150 ppi (pixels per inch) seems to be the minimum number of pixels to produce a good print. Less resolution and your eye begins to resolve individual pixels and the picture edges become blocky or jagged. Use of a higher resolution, in general will produce a better picture, larger file sizes, and the need for bigger memory cards. Larger files also make a faster computer desirable. For my 3 magapixel camera, 150 ppi was fine. For my 7 magapixel camera I have settled on 180 ppi for my general photography needs. Testing will reveal the best compromise for your camera. The average viewer will not perceive the difference between a 150 ppi print and 300 ppi print of sizes 8x10 or smaller.
Will more Megapixels produce a better photograph?
Practically speaking, No. But, there are many compromises to consider. The most immediate benefit of more pixels is the ability to make bigger prints, not necessarily better prints. The question to be considered: how big is big enough? I have determined that an 8x10 is probably as big as I will need. The majority of my picture taking is recording family events and 4x6 or album size prints is all that is needed. I only make larger prints when I get a request for them.
With more pixels comes the ability to crop out a smaller section of the picture. This generally means that you do not need a camera with a huge zoom lens. Most people can not hold a lens of more then 200 mm focal length steady without having image stabilization or using a tripod.
The trade off of more pixels over a longer focal length lens, is a reduction in bulk, weight, and cost of the camera.
As more pixels are placed on a sensor of a given size, each picture element gets smaller. The smaller the picture element the more difficult it becomes to record the photograph correctly. Camera makers are making progress in this area, but today it is still a problem. There is a point where more pixels can actually become a detriment to picture quality. Physical size of the CCD should be a consideration when evaluating a high resolution camera. Another factor is the camera software a manufacture uses to process and save the photograph. Some cameras seem to take better pictures then others, yet they all pretty much use the same CCD image sensors. This why the RAW format is becoming popular. The camera does not process the image, only saves the raw data as it was recorded. Which camera produces the best results is a personal choice. Everyone will have their own idea of what is pleasing. The ultimate factor in the clarity of the picture, is the quality of the camera lens. A poor lens will render all of the above considerations moot. How much digital camera resolution do I need? Canon Cameras save .jpg images at 180 ppi. I have found this to be a satisfactory resolution for my printing needs.
8 Megapixels
Maximum Picture size at 180 ppi 13.6"x18.1"
8"x10" Crop as a percentage of total size 32%
Album size as a percentage of total size 10%
7 Megapixels
Maximum Picture size at 180 ppi 12.8"x17"
8"x10" Crop as a percentage of total size 37%
Album size as a percentage of total size 11%
6 Megapixels
Maximum Picture size at 180 ppi 11.7"x15.6"
8"x10" Crop as a percentage of total size 44%
Album size as a percentage of total size 13%
5 Megapixels
Maximum Picture size at 180 ppi 10.8"x14.4"
8"x10" Crop as a percentage of total size 51%
Album size as a percentage of total size 15%
4 Megapixels
Maximum Picture size at 180 ppi 9.4"x12.6"
8"x10" Crop as a percentage of total size 68%
Album size as a percentage of total size 20%
3 Megapixels
Maximum Picture size at 180 ppi 8.5"x11.4"
8"x10" Crop as a percentage of total size 83%
Album size as a percentage of total size 25%
Viewfinders and LCD Screens
Optical viewfinders have the advantage of a bright clear image. They are also better suited to following action. They are limited when shooting close, because there is a physical displacement between the lens and the viewfinder. This parallax difference becomes more pronounced as you get closer to the subject.
It is always wise to look through the viewfinder of any camera you are considering. Not everyone's eyes are the same and a blurred image may result for some. Cameras with diopter adjustments will assure a sharp clear image for all. People who wear glasses should also be certain they can see the all of the image in the viewfinder. Optical viewfinders as a general rule will only show about 85% of the image recorded. This is partly why most compositions can be improved by tighter cropping. Optical viewfinders are limited to zooms of about 4 to 6 times. They become too expensive to manufacture beyond that point.
The EVF, or Electronic Viewfinder is a small LCD screen used in place of the optical viewfinder. At present they come in two sizes, .33" and .44". The smaller LCD is of low resolution and not very practical. The larger LCD has better resolution, but is still not on a par with an optical viewfinder or a true SLR camera. EVF's can be difficult to use in low light situations and can interrupt action while the camera is focusing and determining the exposure. Most EVF's will show 100% of the image.
The LCD screen is one the great features of digital cameras. You can immediately review a photograph and decide if it needs to be retaken. Practically, the LCD is only good for composing the photograph and shooting close ups where parallax becomes a problem. They tend to be too small and too coarse for focusing or evaluating exposure. They are also difficult to see in bight sunlight. There are hoods available to help in these conditions. Following action with an LCD is difficult and requires considerable practice.
Exposure / Light Meters
All digital cameras today are equipped with light meters for determining proper exposure. The less expensive cameras will seldom offer any form of light meter controls, they just read the scene and set the exposure. As the camera gets more sophisticated more options become available.
It has been determined that an average scene will reflect 18% of the light falling on it. Exposure meters are calibrated to expect this condition and set the camera accordingly. The light meter does not see what you are photographing or have any idea what results you are trying to achieve. Anything that deviates from 18% reflectance will cause the light meter to improperly set the exposure. This is where the photographer must recognize the limitations of the exposure meter and manually over ride it.
The most common situation that deviates from average are scenes where the subject is back lighted. The background is brightly illuminated and the side of the subject facing the camera is in shadow.
Some cameras have a back lighting mode that will increase the exposure to retain detail in the shadows. If your camera doesn't have a Back lighting mode, follow these guidelines. If the subject is fairly distant from the camera, increase the exposure by 1 f/stop (double the exposure). If the subject is close to the camera, increase the exposure by 2 f/stops and turn on the flash if possible.
Other situations that will confuse the exposure meter are, scenes that are predominantly light, such as light colored sand at the beach or snow, light reflecting off of water. Opposite that is where the scene is made up of predominately dark tones. Sunsets or night pictures where you are more concerned with the mood of the picture, rather then trying to record a full range of detail. All of these conditions are candidates for making exposure adjustments to the light meter.
Light Metering Modes:
Evaluative Metering, also called Matrix Metering
The Evaluative system takes several readings around the frame and processes all of the information to arrive at the correct exposure. This system works very well most of the time.
Spot Metering
The light meter takes a reading of a small area in the center of the frame or some designated area of the frame. Usually illustrated by a box in the view finder or the LCD screen. This method will allow you to get the correct exposure for a specific area of the picture. You will usually have to lock the exposure with a half press of the shutter button and then recompose the picture in the viewfinder before pushing the shutter button all the way down. A person sitting in a patch of bright sunlight with the rest of the scene in deep shadow would be a candidate for a spot meter reading.
Center Weighted (may or may not be on your camera)
This was the original method used when light meters first began to appear in Cameras. Reads the entire frame, gives more emphasis to the center. This method is reliable and falls somewhere between the Evaluative and Spot methods.
The image capture device in a digital camera has characteristics closer to slide film then color negative film. Therefore over exposure of the highlight region in the photograph is of more concern than under exposure of the shadow region. Once the highlights are blown out, there is little that can be done to restore them.
As a general rule, the exposure meter in most cameras will get it right the majority of the time. The meter will almost always put you in the ballpark where you can make final adjustments with Photoshop, no matter what metering mode you have selected. From a practical stand point, the camera will take very good pictures most of the time. For people who put the memory card in the printer or kiosk and print what the camera has taken will be better off using the Auto mode and letting the camera make the decisions. For those who will edit their images in the digital darkroom, optimizing the exposure has benefits.
An image that is properly exposed for editing may not be the best image if you are going to print directly from the camera. In the effort to preserve the highlight region of the photograph, the picture can appear darker than is desirable without adjusting the tonal value in the digital darkroom.