“Let our rigorous testing and reviews be your guidelines to A/V equipment – not marketing slogans”
Facebook Youtube Twitter instagram pinterest

Overview of Digital Still Camera Technology

by Eric Shelton June 09, 2008
What kind of camera do YOU use?

What kind of camera do YOU use?

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

psuedo-D-SLR.jpgManufacturers 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.

Zoom, Compact, and Ultra-Compact Models

Although there is a clear separation between D-SLR cameras and near SLR's the same cannot be said about our next group of cameras. The Zoom camera is smaller than the near SLR, but has almost all of the same functionality. Their category name stems from the fact that these cameras have a good set of optics with a generous aperture and up to 12X analog zoom. These cameras usually come in a good mid-sized body with a fairly large LCD. Nearly all of them have a simple viewfinder or no viewfinder at all and have large controls over scene modes and camera operation. Although most of the bodies of these cameras are about as wide and tall as a compact camera, their larger lens and controls require a thicker body. In most cases their body is twice as thick as a comparable compact camera. These cameras often share the same software with near SLR's and compacts, but offer superior flexibility in shooting compared with the compact cameras.

The Zoom camera's lens offers excellent range and low light shooting without a flash. The cameras are small enough to easily accompany you on your trips, but you won't be putting them in your pocket, and you may find it uncomfortable to hang it from a lanyard in front of you. Unlike SLR's and near-SLR's which when worn clearly feel like a piece of equipment, the less expensive zoom camera often isn't as durable as its larger brethren and can suffer from minor bumps. However, these cameras are relatively inexpensive, being easily under $300 and usually come in a variety of media types. These cameras will sacrifice some image quality for a more convenient size, but aren't so small that they can be dropped into a pocket. They don't normally allow complete control of the shutter or aperture, but normally have a pretty good range of scene modes and menu adjustments. They are large enough to have a decent fill flash, but don't expect the range of the flash to be as far as the zoom range of the camera. One perk is that many of these cameras include optical stabilization to improve stability and reduce blurring at maximum zoom. There will be no shooting in the RAW here. These cameras will usually offer JPG and TIFF options along with a few adjustments.

Compact Cameras

compact.jpgCompacts and ultra-compacts make carrying a camera no more difficult than a wallet. These cameras fit easily into pockets, can be worn around the neck and can be packed with on any trip. Part of their allure, is that when turned off, the cameras fold up to a nice flat box and are relatively sturdy. They are normally small enough to fit in the palm of your hand, and can be under 3/4 of an inch thick when turned off. Some newer models are even thinner than a half an inch!

Compact cameras take quite a few seconds to get turned on. During this time the lens gets into position extending from the surface of the camera up to two inches. These cameras usually have a simple viewfinder or none at all, but most people take pictures while looking through the LCD. Manufacturers are well aware of this tendency and use large clear LCD panels that take up the entire back of the camera. Unfortunately this means there are few spaces left for controls. In order to include the same functionality that the larger zoom cameras have, the compacts must have an involved menu system to include this functionality. This means to make any adjustment, you will be diving into a menu system - possibly several layers deep.

These cameras have small optical zooms, usually no more than 3X and reasonable megapixel ranges (we've seen them as high as 8). They often have some number of special effects for image processing, and are limited to smaller scale recording media like SD and Memory Stick. Although battery life hasn't been discussed up to this point, these cameras offer decent shooting life and normally have custom rechargeable batteries, but you also may find the occasional model that still uses AA or AAA batteries. They have largely inadequate fill flashes, but offer advanced red eye reduction. In order to accommodate this reduction, cameras of this class (this includes zoom, near SLR's, compacts and ultracompacts) will light the flash a couple of times to reduce the size of the subject's pupils before shooting. Moreover these cameras often have an infrared range finder to determine how bright the flash should be lit.

Something akin to all of these types of cameras (excluding SLR's) is that they have a complicated autofocusing and subject finding algorithm. Some of these cameras even have advanced face finding. Yet, all of this measuring and flashing does increase how much time will elapse between when you depress the shutter button and when the camera actually takes a picture. Even some of the best cameras will take over a second to actually shoot a picture after having depressed the shutter. This is why most of the cameras have an autofocus indent. When pressing the shutter button half way you will feel a stage one stop that will make the camera autofocus and range find. The camera is now ready to take a picture and will release the shutter after a moment's hesitation after depressing the shutter button the rest of the way.

The major players have reached some limitations on what they can include in their cameras. Although the megapixel density increases marginally with each iteration of the cameras, the software functionality is really the only thing being actively updated. However, since many of these cameras are quite inexpensive, some people are beginning to treat them as disposable, updating their camera often.


ultra-compact.jpgUltracompact cameras are everything their name implies. These cameras can slip into a pocket, in some cases almost unnoticed. Their optics are small and often not in the center of the camera (somewhat distorting their field of view. Many have dispensed with any viewfinder at all instead having a large LCD taking up the entire rear panel of the camera. These cameras will have a simple fill flash and several shooting modes. Some even have marginal analog zooms, however since the lenses of these cameras do not extend far beyond the body, their optics are going to be the worst of the bunch. Arguable, since no amount of electronics can make up for bad optics, you are going to shoot the least technically good pictures. However, they are still going to be much better than any cell phone picture and infinitely better than not having a camera at all.

Many manufacturers have even done work to make these cameras more attractive to people beyond just kids and moms. Some have touch screen controls on the LCD to make it easier to get to the camera's functions, while others have added some advanced sharing features. These cameras make a great second camera to take out to the beach or a theme park. Their flashes are quite limited so unless you only want to shoot faces, they are not going to produce great pictures indoors or in low light. They can light up the subject, but often nothing else.

In the Box

No matter what camera you choose to buy, remember the whole point is preserving memories. Although not addressed here, all cameras are going to come with some rudimentary software for cataloging and editing photos. Don't expect anything too phenomenal here since the margins on cameras have fallen drastically over the past two years and companies are not including many extras. Additionally, most of these cameras will use a custom battery and spares will not be cheap (check eBay for deals). Some cameras indicate they can only work with one operating system or another, but this always refers to the included software and not the camera itself. Some manufacturers differentiate themselves by providing services after the picture is taken. Kodak, for example, has an extensive suite of utilities that will allow you to manipulate, edit, and catalog your photos. From there you can order prints and packages directly from the interface. Others contract out to secondary services for similar functionality. Both Microsoft Windows and Apple Mac OS X provide some level of photo handling, most notably the iLife suite from Apple. Lastly, most camera manufacturers have adopted the universal Pict-Bridge standard which allow cameras from any manufacturer to communicate with enabled printers without the need for a computer. This will allow you to use the LCD of your camera to locate, enhance, crop, and then print a photo all without ever touching a computer.

Have fun and shoot lots of pictures - and remember to back them up! Even the most dedicated pro will shoot hundreds of photos in order to get one gem. Deleting photos doesn't cost anything, and to the photographer in all of us, nothing beats getting that one lasting memory.