Overview of Digital Still Camera Technology

There is nothing like the daunting task of buying a new camera. From the number of choices to the fanboy salesman at your local big box retailer it's hard to not only commit to buying that first camera, but also to figure out the type of camera you need. The photo enthusiast may remember with fondness shooting on film and waiting patiently for those photos to be developed. Today, the work of an entire darkroom or processing machine can be recreated, albeit not of the same quality, on your desktop. Today's photographer shooting in digital can nearly replicate the quality of film productions at a fraction of the cost. Although film is still infinitely more detailed than digital, (consider that the “pixel” on a piece of film is the size of silver oxide molecule!), digital adds flexibility and instantaneous results; something that film can never deliver.

A quick survey of camera types yields ultra compact, compact, zoom, pseudo D-SLR, and a full D-SLR. The article will attempt to give a bit of background as to the advantages and drawbacks to each type of camera. However, before we look into specific type of cameras, there needs to be a moment or two spent on camera brands. Although there are plenty of people who will swear by a single manufacturer, in the camera world, few of the parts are custom made. Many of the same camera manufacturers use the same CMOS and CCD manufacturer, or LCD's, lenses and the like. This article will not attempt to speak to manufacturers, but will attempt to identify the strengths and weaknesses of the different types of cameras from a real-world use perspective.

Digital Single Lens Reflex (D-SLR)

Beginning with the heavyweights of the market, the Digital Single Lens Reflex, or D-SLR, cameras represent a replacement for SLR film cameras of the past. Although large in physical size, these cameras use that size to provide you with a real film replacement. Their name comes from their construction. They have a single large aperture lens (meaning the lens has a large diameter and can let in a large amount of light). Furthermore, through a sequence of mirrors, light from the main lens is split so that a portion of it is sent through the viewfinder. The photographer then sees exactly what is being seen through the lens. In these cameras the main LCD will not show a realtime view of what the lens is capturing, and to take a picture using one of these cameras, you must capture your shot while looking in the viewfinder.

D-SLR's are not the same as their 35mm counterparts. The film cameras that were being replaced presented an image on film stock that is 35mm and has an image area 24 mm tall. The D-SLR camera's have a sensor (depending on the manufacturer) that is around 6 mm tall. This means that if you are used to shooting on film with a standard SLR, all of the focal distances of your standard shooting ranges will have to have a 35mm equivalent focal length. So, a 55mm lens (standard stock lens on most D-SLR cameras) will actually have an equivalent focal length of about 12 mm. What does all of this translate into? Well, if you are moving from shooting 35mm film, you are going to have to face the fact that your equivalent focal lengths will all be shorter and therefore your actual field of view will be different than what you may have been used to. If you have never shot film before, none of this may matter to you.

What truly separates the D-SLR from other cameras is that you have full control over the camera, this includes shutter speed (how long light enters the camera), aperture size (the amount of light you allow into the camera) and focus. Moreover, D-SLR cameras usually offer a multitude of image processing controls that can be rendered to your image on the fly, or the ability to have the image completely raw off of the sensor (called shooting in RAW). Lastly, the bodies of these cameras are designed to be extendable. This means that a stock body can accept a full range of lenses from wide angle to telephoto; and these lenses can be ultrasonic autofocusing and optically or electronically stabilized for a crystal clear image in uncertain shooting environments. Not to mention that your simple fill flash can be replaced with longer reaching and more adjustable flashes.

Probably, the most sought after quality of the D-SLR is the fact that it takes a picture the moment you press the shutter button. These cameras are ready to use almost immediately after they are turned on and can shoot images, once focused the instant the shutter button is pressed. Most people who use digital cameras complain that even when their camera is ready to take the picture there is a delay in getting the camera to take the picture.

All of these features come at a cost. If you want to get a taste of a D-SLR, you are going to lighten your wallet by $500 for an entry level body. This doesn't include the lens (although must manufacturers include a kit lens with your purchase of their base level camera). Beyond entry level, bodies can range up to several thousand dollars for a full featured professional body. The money here goes into faster electronics for faster burst shooting, heavier duty cycles, and more elaborate controls. Although all of these cameras have auto-shoot modes or scene modes (portrait, backlight, action, landscape etc....) they also include fully manual control over your shooting. However, what you spend on a body can easily be dwarfed by what it might cost to get a high quality lens. Lenses range from the low $200 for a kit pack to $8000 for long range telephotos. Even the least expensive SLR lens will likely shoot a better picture then the most expensive compact camera.

These cameras traditionally do not allow you to shoot by looking at the LCD since the LCD's do not provide you with a "live" image of your target. None of them allow for a movie mode and most have large megapixel sensors so the image size is big. They are physically large in size and, though they have many automatic features, can be difficult to use effectively. Since they are designed with professionals and prosumers in mind there are often dozens of features that are simply unnecessary for the average user, and moreover, many of the add-ons are financially out of reach for the casual photographer. Although companies like Nikon and Canon have made inroads to consumers with their D-20 line and Rebel line respectively, the mere fact that they can't be dropped into your beach bag or a pocket limits how often you may take the camera out.

Technical Note: Some new D-SLR cameras are now offering parallel "real-time" LCD viewing. Particularly, models from Canon and Sony are pioneering this new technology, but it's so new we haven't been able to evaluate if there are any drawbacks as of yet.

D-SLR Bottom line: If you want the best looking photos with the most opportunities for expansion, these are definitely the way to go.

Near D-SLRs or Large Form Factor Zooms

Manufacturers also know that people may demand SLR performance, but be unwilling to deal with the complication, size or expense. To fill that market there has been a rise of near-SLR cameras. These cameras normally come with large aperture lens that cannot be replaced. They have either an electronic viewfinder, or a simple viewfinder. (A simple viewfinder has its own lens and is nothing more than a window through your camera. It approximates what the lens is seeing). However, they usually have large LCD's (as big as 3 inch) with a live display for shooting.

Since these cameras are attempting to be similar to SLR's they usually have lens and flash accessory mounts. They usually are in the larger megapixel range (8 to 10 megapixels) and often have some unique extra features, such as wireless connectivity to printers and computers. Since they have large lenses, they have great aperture control. These cameras normally have long optical zooms upwards of 10x (an optical zoom is the ability of the lens to increase the focusing range as opposed to digital which simply zooms in on a section of the current image, often degrading the quality). Their large aperture also gives them the ability to take pictures in low light conditions. Lastly, since the camera body is fairly large, they can afford to have larger controls - and more of them. This means less adjustments need to be made through menus and more direct access to the camera functionality is provided.

The near-SLR have some drawbacks. First, although they have excellent controls, they are not SLR's; therefore, they still have the obligatory pause when attempting to take a picture. They might be quicker than other cameras but it is still there. Further, many of these cameras are nearly as expensive as the SLR's they are attempting to mimic, and some are almost as large. The accessories you buy for these cameras are not transferable to another camera, so if you upgrade you will also need to upgrade your accessories. The primary benefit of this camera is for the photo enthusiast who wants control over the functionality of the camera, and also wants to shoot using the LCD.