The magazine of the Melbourne PC User Group Digital Photography Purchasing a Digital Camera Larry Horn

Digital cameras are the latest "Must Have" toys for gadget loving computer users and many others. The reason computer users love digital over regular film is the computer gives them the ability to make endless changes, corrections, and improvements to their pictures and use them in creative projects. This article will be my very opinionated list of what you should consider before purchasing a digital camera, or getting your new one with more features. Remember, technology in this field is advancing so fast with more resolution and features for less money on a monthly basis. Therefore any recommendation for a specific camera is obsolete before the article can be printed.

An important point: No consumer level digital camera of today under US$3,000 will equal 35 mm film for absolute image quality! The structure of film is way beyond 3 or 4 MegaPixels (MP), and film has grain which softens the edges presenting a more natural picture to your eyes. Additionally, film cameras can be purchased, at a very reasonable cost, with interchangeable lenses which greatly increase the flexibility of the camera use. Yes, you can fake a telephoto lens in the camera but that kills your resolution. (I will get into that below.) You can also scan a photo, but that will reduce the resolution and ultimate image quality. When you get your film developed and placed on a CD by the camera store, they actually scan the film (with a very good film scanner) and save the file to a disc.
 
First, why do you want to purchase a digital camera? Because they are fun to use and can actually save you a lot of money over time. It takes the Polaroid® concept of "a picture in a minute" and speeds that up. You take the picture, preview it on the LCD screen, delete it if you don't like it, or save if for future posterity - all at no additional cost for film or developing. Print out the pictures you like (paper quality does matter) or send them as e-mail attachments to friends and relatives.

Let's get down to the actual items to consider when buying a camera. These items are in my order of importance although many of the items are actually of equal ranking and personal preference has influenced it.

Resolution and Sensor Size

The heart of all digital cameras is the light sensitive electronic chip called a sensor. It takes incoming light and converts it to a digital file. This chip determines the maximum resolution and ultimately, image quality. This sensor is made up of a number of individual photo-receptors corresponding to pixels. When a digital camera has 1 MP resolution, the sensor actually has that number of photo-receptors The density of the sensor determines a camera's overall picture quality.
 
Using a lose analogy to relate it to your computer screen's resolution. The original, default VGA resolution of Windows on a computer monitor was 640x480 which means it has 640 dots or pixels across by 480 down, or 0.3 million pixels making up the screen image. A digital camera with this same resolution would have 0.3 million image sensors each representing a pixel or 0.3 MegaPixels (MP). Cameras in the mid-price range (US$150-300) now have 1 MP, or 2 MP. In the US$400-US$1,000 price range you will get 3 MP or 4 MP. This directly impacts upon the size of a picture you can print as more pixels translate into a larger picture that still looks good. The camera has captured more detail and doesn't have to "guess" at or interpolate the missing dots, or expand the existing ones causing a blotchy print.

I have seen two types of sensors: a charge coupled device (CCD) which is usually found in high-quality cameras and a complementary metal-oxide semiconductor (CMOS) which is more common in the low-cost, entry-level cameras. Most of the reviews I have seen favor CCD chips.
 
What resolution do you need?
 
That depends on how you will be using the final output. Yes, more is always better, but as a rule of thumb related to final use. See Figure 1, below. The listing was the consensus of several sources but was plagiarized from the April 2001 issue of PC Photo, an excellent magazine for anyone starting out with digital photography. PC Photo generally used the more conservative, smaller sizes.

One last point on resolution: Many people will want to eventually crop their pictures for a better composition. When you crop it, you effectively throw out the resolution in the area you delete. A 3 MP image could quickly reduce to a 1 MP image with cropping, so if you like to work on your images and make relatively large prints, start with and shoot at the highest resolution you can afford.

The Lens

There are two main points to consider here, lens material and zoom capability. Lenses can be made of glass or plastic. Glass is the hands down winner for quality.

The stated Zoom range is a bit more complex. You can have Optical Zoom and Digital Zoom. Optical Zoom uses the actual optics of the lens to magnify or zoom in on the image. There is no loss of resolution/quality, but it is more expensive to manufacture. Digital Zooms take the original image from only the centre part (how much, depends on the degree of magnification) of the sensor and use the camera's internal computer to interpolate or guess at the missing pixels between the real ones. It is like cropping the picture and then stretching the remaining image back up and filling in the blank spaces. Image quality is degraded and the greater the magnification, the more you lose. A 3 MP sensor might actually be using only 1 MP at the centre and filling in the other 2 MP. Don't get me wrong, I have seen cameras guess very well and produce good quality images at high digital zoom magnifications but optical is always better than digital. The most common range I have seen in optical zooms is 3x, ie. three times magnification.
 
Also, be aware that the sensor is not the same size as a piece of 35 mm film, so when you see the focal length stated in millimetres like 38-115 mm (3x) this is actually a more telephoto angle lens than you would get in a 35 mm camera. PC Photo Magazine lists the conversion at approximately 5x. My Olympus camera has a lens of 5.4 mm - 16.2 mm which they state is equivalent to 35 mm - 105 mm on a 35 mm camera which equals slightly wide angle to short (Portrait) telephoto, for those not familiar with 35 mm cameras.
 
Framing the Picture

You can frame the picture in either an optical, ideally through the lens, viewfinder or with an LCD display panel on the back of the camera. I feel a digital camera should have both! Being a long-time photo enthusiast I am accustomed to an optical viewfinder. LCDs also have the bad tendency to wash out or become too light to be viewable. I also find it awkward to hold a camera away from my face while trying to frame the image. Another disadvantage is that LCDs consume a lot of battery power. You can shoot all day on one set of batteries with an optical viewfinder, but you had better have extras if you use an LCD. I would not purchase a camera without an optical viewfinder. (Our VP, Elliot Glantz, feels just the opposite, and although his camera has both, he always uses the LCD over the optical viewfinder.) I will also admit an LCD is more accurate in framing the subject, especially close-ups, unless your optical viewfinder is through the lens, something generally found only on top-of-the-line digital cameras.

If I am so partial to an optical viewfinder, why do I want a digital camera to have an LCD panel? Because it is invaluable for previewing your pictures to make sure you really got a good shot. If it didn't turn out, you know it instantly and can reshoot it. The bad picture is simply deleted, making room for another shot and with no waste of film. It is also great being able to show off your pictures while still at the party, etc. and see the reaction. One neat feature I saw on a Sony camera was an LCD panel which swivelled so you could still see it if you put the camera over your head or were using the self-timer to take your own picture.

Focus

Simple, inexpensive, digital and film cameras have a single fixed, or two zone focus. It is a compromise or zone guess. This is OK as a quick point-and-shoot camera, but will not give you the best shots. Most better (US$250+) digital cameras have autofocus lenses. This will give you far better, sharper images. An added feature is a focus lock. This feature allows you to lock the focus on the main subject and then re-frame the picture to a more pleasing composition. When you get up to the professional level (US$2,000+) cameras, you can even get optional full manual focus for real creative effects.

Memory - Storage Cards

Digital cameras store their images in non-volatile memory cards; they save the memory even when the camera is off. Some of the very inexpensive have only internal memory which will hold 25-30 pictures before you have to get to a computer to download them. This is OK around the house but would require you to lug a laptop with you on a trip if you wanted to take any additional pictures.
 
A better solution is removable memory cards so you can take several with you and when one is full, just change it like you would film, and keep shooting. There are several, unfortunately non-compatible, options available. These are Smart Media (SM), Compact Flash (CF), Sony's Memory Sticks, Multimedia Cards, Click Disk, the new IBM MicroDrive, and the recently released CD-R. The 2000 Fall Comdex in Las Vegas also saw the introduction of additional formats but these are not yet available. SM and CF are the most popular at this time. They are all small cards, about the size of a matchbook, and slide into the camera. You purchase them by memory size, in Megabytes, which range from 4 MB to 64 MB with the MicroDrive going up to 340 MB. These capacities are increasing as I write this. Some Sony cameras still use a standard 3½" floppy disk. These are cheap but are limited to 1.4 MB so they can't hold many pictures as the resolution increases.
 
The number of images you can save per Megabyte is directly related to the resolution and the amount of image compression you use.

Image Compression - File Type

A non-compressed high resolution picture would take up multiple megabytes of storage space so most cameras store the images in a compressed format. The most common formats are TIFF and JPEG. TIFF uses minimal compression and while it produces the largest file sizes, TIFF produces also the best pictures. JPEG is a "lossy" compress-ion algorithm. This means that some information is thrown away for ever when the file is compressed - so if you compared the uncompressed image with the original, you would find some differences. You can, on some cameras, set the amount of compression so that you determine the amount of data you are willing to lose (and reduce file size) before the image becomes pixilated and looks unacceptable. Setting the camera to Fine, Normal or Basic determines the amount of compression. Some brands use different terms but the concept is the same. I discourage the use of the Basic -highest compression - setting as it gives the lowest quality. A good quality camera will give you a choice of file type as well as degree of compression.

So, how many pictures do I get on a memory card? A basic camera my neighbour has includes only 2 MB of memory and at 640x480 resolution with what it calls fine compression, they can take 16 pictures or 32 pictures at the basic setting. The average camera with removable memory comes with an 8 MB card. Using that as a guide I will reproduce part of a table (with their terms) from the camera I own. Figure 2 below.

The Feel of the Camera

Even with the best specs in the world, if a camera does not feel right you will not use it. This is very subjective but also very important. Getting the size, weight, design, location and operation of the controls, and the general Ergonomic Fit comfortable to you are important. There are some necessary compromises in size and weight if you want every "bell and whistle". You might be carrying the camera all day on vacation so don't over buy on size just to get a feature you may never use. The box of my still camera says it will also take video clips. But when you look at the spec sheet you find out the video is low resolution and limited to only several seconds, even with a relatively large media card. 

My camera gives you only 96 seconds with a 32 MB memory card at 320x240 resolution. Not very practical.
 
Viewing and Getting the Pictures Out of the Camera

I consider it important, but not critical, to have a TV out on the camera. The small LCD screen on the back of the camera makes a poor screen if you have several people to view the pictures. Being able to plug the camera into the TV, especially if the camera has a slide show feature, is very nice.

There are several way you can get the pictures into your computer. The oldest and slowest is with a serial connection. All PCs have a serial port so you are "guaranteed" a connection. The preferred method is with USB. It is many times faster and almost every computer supports USB, and you can hot-sync with USB, you don't have to reboot to connect the camera as you probably do with a serial connection. Even if your camera has only a direct serial connection, you can still use USB by purchasing a media card reader. Plug the reader into a USB port, remove the memory card from the camera, place it in the reader and your computer now has an additional drive letter, making it fast and easy to copy your pictures. They even make adapters that look like 3½" floppies, into which you can put the memory card.

Part 2 - What Next?

I have tried to cover the more important considerations in purchasing and using a digital camera. You should first decide how you will use the camera before drawing up your spec sheet. It is very easy to be seduced by features that sound great but you may never use. Also, be aware that as with computers, technology advances daily (or is that hourly?) and prices generally are headed downward. The maker of my brand camera just last week came out with the new model number that has a 10x Optical zoom for less than I paid with a 3x Optical zoom. Don't over buy! Start out with a starter camera, see how you like it and keep track of the features you love or wished you had. Then move up to a camera with those features, which will probably cost less at that time than you paid for the starter camera.
 
My starter camera for general use would be 1 MegaPixel, removable media (not floppy), and flash. A 3x zoom, TV out, USB, an LCD and Optical viewfinder are next on the list. Eliminate the zoom and the Olympus Brio 100 or HP 215 are good choices for US$200-250. If you are really unsure and just want to test the waters, try a JamCam or one of the US$50 to US$100 cameras as a starting point and then give it to the kids as you move up.

It is also important to remember that despite whether the camera uses film or digital media, you are still taking pictures, so a good photography book or magazine, like PC Photo, will be helpful.

Now that we have the basics, what are the other features you will want to consider? The technical term for most of these are the bells and whistles.
 
Exposure Control

This touches on several different features. The first one is White Balance. White balance is equivalent to adding a filter to make the whites look white, not blue or yellow as you get under fluorescent or incandescent lighting, respectively.

Another related feature is exposure compensation. When you take a picture in a high contrast situation, like a person in a dark room with a bright light or window behind them or outside with the sun behind the person, the camera's exposure automatic controls may be fooled resulting in a dark (under-exposed) subject with a properly exposed back-ground. When shooting in this type of situation, a look at the picture on your LCD will tell you if it is OK or needs to be deleted and retaken with fill-in flash or an adjustment to the exposure. An Exposure Lock feature is useful here.

Remember, if you are using flash, an on-camera flash has a very limited range, usually 8-10 feet. To increase the range you will probably need a hot shoe on the camera to add a second more powerful one or a sync outlet. (These are found only on high end, expensive Pro-sumer cameras. If you've never used one with your film camera, you're unlikely to need one on a digital model.) Red eye reduction flash or slow sync features are also desirable as you get more experienced in creative photography.

Speed of Taking Pictures

Many digital cameras take from several seconds to one minute to get ready for the first shot. This seems like an eternity when you are trying to get that quick spontaneous shot. Next be aware that there is usually a delay between pressing the shutter release and actually capturing the picture. Waiting for that perfect moment in the action or expression will result in disappointing missed shots. Anticipation is critical. Lastly, the camera may need time to record the picture on the media so rapid fire sequence shots may be difficult. Some new cameras overcome this by having internal memory that captures the pictures quickly and them writes it to the slower removable media.

Power - Batteries

First - digital cameras "eat" batteries. Most cameras use standard AA batteries. These are preferable to proprietary ones which may cost more, may be harder to find, or not be removable so that you have to tie up the camera to recharge them. When it comes to AA batteries you have a choice of several kinds. Single-use alkaline batteries tend to die quickly, especially if you must use that LCD screen to shoot the picture. However, the upside of them is they can be found any place and are a good back-up. Rechargeable batteries can be nickel-cadmium (NiCad) or nickel metal hydride (NiMH). I recommend the NiMH as they last longer without the "memory effect" of NiCads and despite their higher initial cost, will save you money in the long run. To recharge them, just put them in a charger and plug it in. I recommend two sets if you plan a full day shooting, like on vacation, as they do take time (hours) to recharge. Some cameras will also work off AC wall outlets which is good for showing the pictures on your TV without depleting the batteries.

In-Camera Special Effects

As competition grows, many camera companies are starting to add in-camera features. These include Close-up/Macro capabilities, Slide Show display of the pictures on the camera's LCD or a connected TV, Multiple Images at once on the LCD - good for quickly finding a specific picture, and Magnification of the image on the LCD; the small size of a LCD screen makes this valuable, to get a better look.

I have even seen in-camera effects like sepia toning and special borders for some cameras. I would not use them as I prefer a straight original that I can modify on the computer.
 
Software

Almost every camera comes with software. While the TWAIN drivers are necessary to have the camera communicate with the computer, the photo editing software is generally underpowered. You will quickly want to upgrade to a full-featured program like Adobe Photo Elements, MGI Photo Suite, Microsoft Picture It! or Ulead PhotoImpact. These programs are generally easier to use and give you better control than the free software in the box. It is nice to get started with, but don't judge the camera by the software.
 
Other Features

Some cameras are adding features that do not make much sense to me. These include MP3 playback, Video and Audio recording. MP3 steals memory so you can't take as many pictures and Video recording is very brief and of poor quality. Audio makes some sense to add short notes on the picture but occupies memory, cutting down on the number of pictures.

Education

I mentioned it before, but it is worth repeating. No camera will make you a great photographer. Get some photography training. Even the major film companies like Kodak are into digital today. They even have the Kodak Digital Learning Center at http://www.kodak.com/US/en/digital/dlc/index.jhtml. You can also try http://www.cnet.com and http://www.techtv.com for their guides.

My Camera

OK, I promised to tell you what I purchased. Remember, that was last year, and while I am still very satisfied with the camera, newer models might change my purchasing decision. I have an Olympus D-490. It is a 2.1 MP camera with both 3x Optical Zoom plus 2x Digital Zoom, an Optical view finder and an LCD, Removable Media (Smart Media), Preview/review with Multiple and Magnify as well as a slide show feature, small (pocketable) size, exposure compensation, focus lock, macro (close-up) capability, self timer, tripod mount, uses AA batteries (std alkaline or NiMH rechargeable ), and has a TV out. (Current street price about US$400.) This has been superseded with the model D-510 which added a longer digital zoom and USB as well as a burst mode to take 2 frames per second - all for less than I paid. They have also come out with a C-700UZ which added a 10x optical zoom that looks very attractive (around US$500). My son uses an Olympus D-460 which is almost identical to my D-490 but is only a 1.3 MP camera and he is very satisfied with it. I purchased mine, in part, because I had used and liked his.

Don't be overly influenced by what I purchased. Go out and try them and see what you like within your budget.

Reprinted from the November 2001 issue of PC Update, the magazine of Melbourne PC User Group, Australia

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