Digital Corner 
Digital Cameras , YES!
Part 1

May 18th, 1998


If Lewis Carroll were alive today, this passage from Through the Looking-Glass might read: "The time has come," the Walrus said, "To talk of many things: Of shoes - and ships - and sealing wax - Of cabbages - and kings - and, oh yes, digital cameras.

The "talk" stage is over now, and it's time to make a decision. Carroll, whose real name was Charles L. Dodgeson, was a math professor who lived from 1832-1898, and would have laughed heartily at my massacre of his poetry because he was an avid photographer.

Unfortunately, most of his work is under lock and key -as he would be, today- because his genre was taking nude photographs of pre-pubescent girls (with the enthusiastic approval of their parents, incidentally). But those were different times...a more innocent age, and a subject, perhaps, for a future column on digitally re-creating the look and feel of Victorian photography.

The reason it's the right time to buy your first digital camera is that the field has begun to stabilize and the distinction between images produced by a film cameras vs. a digital ones are becoming blurred (no pun, intended) to the point where you cannot always tell one from the other. Furthermore, you can now buy some outstanding digital cameras for between $500 and $1,500, a price range that would have been unthinkable just a year ago.

Few things are more thrilling than shooting pictures with a digital camera and then ­with hardly any steps in between­ seeing them splash onto your computer screen and flow smoothly into your image editing program. It's the same as watching the birth of a photographic print in a developer tray, or experiencing the chills that accompany unwinding still-wet negatives from a reel and holding them up to the light.

Of course, if you need a reason, other than being on the cutting edge of photography, to buy one of these cameras, consider the following advantages: instant image checking after you shoot, no scanning, no film costs (which encourages creativity), and promoting a cleaner environment. Whatever your motivation, this column will acquaint you with the basics of digital photography. Part 2 will go into details on specific cameras worth considering.

Camera Resolution

No discussion about digital cameras and imaging can avoid the subject of resolution. Simply defined, resolution is the ability of a device to record fine details in an individual threads in a sweater or separate grains of sand on a beach. Images from digital cameras (and scanners) are made up of little squares (sometimes rectangles) called pixels. Pixel is short for "picture cell" or "picture element."

A digital camera's imaging surface is made up of rows of tiny individual light sensors that capture color and light information which is then electrically converted into digital data­the cells or pixels that make up the image. If a camera is capable of capturing an image that consists of 640 horizontal by 480 vertical pixels, it is said to have a resolution of 680 by 480 pixels or 307,200 pixels (arrived at by multiplying the two dimensions).

Thee total sensor array is called a charge-coupled device (CCD) and is used on most digital cameras now on the market. However, some cameras are being built around complementary metal oxide semiconductor (CMOS) devices which are more reasonably priced and require very little power compared to CCD sensors. More about CMOS digital cameras in a later column.

Higher Is Better

The more pixels that can be packed into a given area, the higher the resolution­ resulting in a finer-detailed image. Think of it as using graph paper to help you draw a picture. The more squares per inch, the more nuances you'll be able to capture. Higher is better when it comes to digital cameras. Buy a camera with as high a resolution as you can afford if you want to make prints 5" by 7" to 11" by 14". Reasonably-priced digital cameras are now available in the 800,000 to 1.4 Megapixel range that will satisfy that requirement.

At this point, I'd like to dispel the myth, perpetrated by photographers in defense of traditional film-based imaging, that digital resolution is not -nor can it ever be- as high as film resolution. Wake up! It's higher. If you don't believe me, ask Kodak. Digital capture is capable of far more resolution than's just that at this point in time it's a fairly expensive purchase for the average photographer, exposure times are relatively long, and the computer files generated are quite large. But that will does everything in electronics that we first consider impossible.

But even now, most catalog photographs are being shot digitally with a special back that fits on most professional cameras. The old axiom that says you can have any two elements...quality, speed, or economy, but not all three, has been shattered because the quality is outstanding, the results can be seen immediately, and the systems pay for themselves in one to two years...saving huge amounts of money in film, processing, and re-shooting expenses thereafter.

Lately, specifying digital camera resolution has become a bit tricky because you have optical resolution (the actual number of sensors in the array) and interpolated resolution, which uses software magic to kick the optically obtained image to a higher resolution by artificially adding more pixels. Some camera manufacturers fail miserably at this, but others, like Agfa, do a magnificent job and the software process used to do the interpolation when images are transferred to computer from all but their lowest cost camera is called, appropriately, PhotoGenie.

I recently shot a picture of one of my cats using an Agfa ePhoto1280 and printed it at 8" by 10." You can see every hair as well as subtle gradations in blacks, tans, and greys...and this from an optical resolution of only 810,000 pixels interpolated to 1,228,800 pixels where about a third more pixels have been added to the image to increase its resolution. Agfa claims they're using artificial intelligence which sounds like a bit of hype; nevertheless it works well.

Click the image to enlarge

Kodak starts off with rectangular cells in some cameras which they then convert to square pixels. Thus a CCD consisting of 984 by 850 rectangular pixels is converted to 1280 by 960 pixels. The advantages of this are a smaller file size (greater storage capacity) and lower cost than offered by a CCD that is a full 1280 by 960 pixels. The resultant image is slightly softer in the horizontal direction than an image captured with a CCD that is a full 1280 by 960 pixels but Kodak says you can adjust for this softness, if needed, using a third-party, image-editing application.

Of course, if you've used an imaging program you know that you can only interpolate (or upsample) so much before you begin to lose sharpness. So like everything else in life, it's a trade-off...although since the interpolation on digital cameras is not extreme, you probably won't be unhappy with the results.

The rule of thumb for buying your first digital camera is that it should have 1,000 pixels or more as one of the numbers describing its resolution. Incidentally, most cameras offer a choice of high and low resolution modes. Use the higher one if you want prints, and the lower one for web images or for sending photos as email attachments.

Higher Is Bigger, Too

Of course, the higher the resolution, the larger the file size­ even though most images are compressed in the camera using JPEG (Joint Photographic Experts Group) encoding. At first, you'll probably want to save every gem you've shot, so expect your hard disk to fill up fast (a good reason to buy a removable drive, with plenty of cartridges). Your file sizes will depend on the specific image and the degree of compression you choose (user selectable on many cameras).

Figure that an uncompressed image will be roughly five to twenty times larger than its compressed size. A 640 by 480 pixel image compressed to 50K will inflate to about 900K when opened in an image editing program. A 1,024 by 768 pixel image compressed to 200K expands to 2.25MB. And when you get up to 1,280 by 1,024, a 900K JPEG balloons to 3.75MB. With some cameras that let you shoot and save uncompressed images, file size can mushroom to 5.6MB.

That's only the beginning. If you do any editing on images, you won't want to re-save them as JPEGs, because JPEG is a lossy compression method. This means that to reduce file size, some of the image information is lost; once gone, you can't get those pixels back without starting over from your original image (and always work from a copy, never the original). So save images in the Tagged Image File Format, (TIFF or .TIF) with LZW lossless compression, if available, to save space.

To make it simple, bring the image into your imaging program and then, before doing anything, save it as a TIFF. Then you can begin working on it and it will always subsequently close and re-open as a TIFF, eliminating the risk of it being closed as a JPEG and becoming further degraded if you open it again to do some more work on it.

Patience Is a Plus

The first time I transferred images from a digital camera through a serial port to my hard drive I was too excited to notice that each one took about 30 seconds. Doesn't sound like much, but when you transfer 40 exposures, that's a minimum of 20 minutes. Plus, it takes still more time to rotate those vertical shots upright so you don't twist your neck out of shape viewing them.

Then, once downloaded, you must separate the good, the bad, and the ugly. So far, there's no easy way to do this. The "digital contact sheet" displayed prior to downloading isn't ­as they say where I live­ worth spit. The images are too small and you can't see detail. So, expect to end up transferring most of them. And when they're finally aboard, it's not easy to position them side-by-side on the screen without resizing them and fiddling even more.

All this is changing, of course. You'll soon be able to routinely transfer scores of images in a flash (literally) and software will eventually take care of positioning and selection. But for now, prepare to have your patience tested.

Imaging Software

You'll need a photo imaging program to transfer and work with your pictures. Most digital cameras include plug-ins that you add to the program to simplify this process. Adobe's cross-platform PhotoDeluxe is bundled with many cameras. You can also opt for the de facto industry standard, Adobe Photoshop which, incidentally, after four iterations has finally added multiple undo-redo in its latest version, Photoshop 5.

While a plug-in is the easiest way to get images out of the camera and into a program, many digital camera manufacturers are now including their own stand-alone programs that will allow downloading to a folder or directory. Some even have limited editing capabilities and, until you pick the digital imaging program you want to marry (divorce not being an easy option in this field), you can do a bit of refining with them and then print out your results.

Light Sensitivity

Unlike conventional cameras where you can select films with different sensitivities to light, all digital cameras in the under-$2,000 price range, except one, offer only a pre-set sensitivity to light, usually a film-equivalent ISO of 50 to 200. It's not a big limitation, though. Many of them take perfectly acceptable pictures under low light conditions because their lens apertures are pretty fast, usually around f-2.8. As a standard feature, most have a built-in flash for really abysmal conditions and for filling in deep shadows on sunlit, high-contrast subjects. And when it comes to freezing action, some even have shutter speeds up to 1/16,000th of a second!

What you may find disconcerting, at first, is the slight time lag that occurs between pressing the shutter release and the actual exposure. That's when the camera spends a fraction of a second going through its pre-shot calibration and white-balancing act. But as a bonus, if you shoot under fluorescent lights, for example, you'll get perfectly color-balanced pictures instead of ghastly green ones. There's also some delay between shots while the camera processes and compresses the image. You'll quickly adjust to these quirks, though, and things are improving every day...some cameras can now even take multiple shots per second at their lower resolution settings.

Avoid the Shakes

Even the best digital camera will seem like a poor choice if you can't keep it still when shooting. Favor cameras that have conventional optical viewfinders or through-the-lens reflex viewing, and look for cameras you can steady against your head to avoid camera shake. Cameras that provide only an LCD screen to view the image you're going to shoot may look nice sitting in a camera store, but they require that you hold the camera away from you to frame the shot, which creates unsteadiness and tired arms. Also, the LCD image washes out if you shoot outside with the sun at your side or back. Exceptions are cameras with viewing screens that swivel to allow you to look down into them while holding your elbows relaxed at your side.

Screens, Batteries, and Storage Cards

Shakiness aside, cameras that have integrated LCD screens (or as accessories) in addition to a regular viewfinder are quite useful. They're great for checking the quality of pictures you've already taken and can help you pre-frame tight close-ups shots, preferably with the camera on a tripod.

Some cameras allow you to view images on a television screen. This is a handy feature, especially if you want to check a large view of your shots when you're traveling and don't have a computer handy. You can also use the camera for presentations by pre-recording your pictures in the correct sequence on a storage card. Just make sure you buy an AC adapter if it's not supplied with the camera and remember that vertical shots will display as horizontals on the screen.

You will need rechargeable batteries and a charger if they don't come with the camera. Most digital cameras eat batteries like candy, especially since they must power the flash and the LCD screen used to preview and post-view shots (if the camera has an LCD). The best batteries for most digital cameras are QUEST Nickel Metal Hydride (NiMH)...made in the USA by Harding Energy. I have found that NiMH batteries called "Clean Cell" from China that are supplied with some cameras have a very short service life before they need recharging.

Q UEST batteries hold a near-constant voltage when in use and I've found they last two to three times longer than other rechargeables. Unlike Ni-Cads (which I detest) you can fully recharge them anytime because they have no memory problems and they can be recharged with any Ni-Cad charger you may already own. Although they can take up to 16 hours to recharge, they are so inexpensive you can buy several sets so you'll always have enough on hand. If fast recharging is a must, a special fast charger will be available soon.

Most digital cameras now use removable storage cards but there's no established standard. The SmartMedia Card holds great promise because in addition to being able to transfer images directly from the camera to your computer, it can also (with appropriate adapters) pop into a PC card reader or directly into your floppy drive for even faster cable-free downloading. Don't confuse this capability with Sony cameras that use standard high-density floppy disks; the SmartMedia card is about the size of a large postage stamp and uses a Flashpath adapter that slips into your floppy drive.

Checking Image Quality Before You Buy

I also suggest you check out camera picture quality at different resolutions before you buy. Some camera manufacturers offer sample images on their Web sites and I'll list the sites in my next column. But if you're over-eager and beat me to it, make sure you don't print the images from within your Web browser because your output will be locked at the screen resolution of 72 or 96 ppi. Instead, download them as files and then open them in an imaging program of your choice. From there, print your samples at different resolutions and sizes to see for yourself how they'll look. It's a great way to see what you'll get before you buy.

Finally, zoom lenses for digital cameras now come in two flavors...optical and digital. To make matters even more challenging, some cameras incorporate both. On a digital camera with an optical zoom, the resolution remains the same regardless of the focal length you choose. But a digital zoom uses only part of the sensor array -exactly as if you'd cropped the image- and the resolution drops accordingly. The new Olympus D340L, for example has a resolution of 1280 by 960, but using the telephoto mode or the sequence shooting mode produces images that are only 640 by 480. To put it simply, just remember: "Optical zoom, good; digital zoom, bad," unless you're shooting only for the web or for CD-ROM multimedia productions, in which case it doesn't matter.

Now's the Time!

Whichever digital camera you choose, keep in mind that it probably won't be the only digital camera you're going to own. It's rather unlikely you're still using a 35mm camera without autoexposure or autofocus. Even though the future promises better hardware with more features, while you wait for your ideal digital camera to appear you'll be missing out on learning how to use this fascinating new photographic medium.

And then there's always the competition...if you wait too long, your contemporaries will be at ease with digital photography while you're still looking on from the sidelines. In my next column, to help you make some informed decisions and minimize "buyer's remorse," I'll suggest some excellent choices that will stand the test of time...well, for at least six months, anyway :-)


QUEST NiMH Batteries

As these batteries are in great demand, I've listed the four biggest dealers in the U.S. To keep the price of the recharger reasonable, the red lights don't go out when the batteries have reached full charge, so keep an eye on the clock. They won't be harmed, though, if they sit in the charger for long periods of time, although they'll get rather warm.

Norman Camera
Kalamazoo, MI

Calumet Photo
Chicago, IL

Reno, NV

Porter's Camera
Cedar Falls, IA

Arthur Bleich