TCS - Digital Photography - Purchasing a Digital Camera
Digital Photography
Purchasing a Digital Camera
by Larry Horn
From the August 2001 issue of the I/O Port Newsletter
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. (Be sure to attend this months meeting where MGI will show you some of the digital
editing techniques and tricks you can do using their line of products.) 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a specific camera is obsolete before the article can be printed.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 $3,000 will equal 35MM 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 also 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 disk.
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 (r) concept of a picture in a minute and
speeds that up. You take the picture, preview it on the LCD screen and 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 says it has 1MP 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 .3 million pixels making up the screen image. A digital camera with this
same resolution would have .3 million image sensors each representing a pixel or .3 MegaPixels
(MP). Cameras in the mid-price range ($150-300) now have 1MP, or 2MP. In the $400-$1,000 price
range you will get 3MP or 4 MP. This directly impact 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" or interpolate at the missing dots or expand the existing ones
causing a blotchy print.
I have seen two kind 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:
| .3MP | (640x480) = On screen viewing, Web Sites, sending as e-mail attachments, prints up to 3"x5" |
| .8MP | (1024x768) above and prints of 3"x5" to 4"x6" |
| 1 MP | (1152x864) = 3"x5" to 5"x7" |
| 1.3MP | (1280x1024) = 4"x6" to 5"x7" |
| 2 MP | (1600x1200) = 5"x7" to 6"x9" |
| 3 MP | prints up 8"x10" to 11"x14" |
| 4 MP | 9"x12" |
The above 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 down, you effectively throw out the resolution in the area
you delete. A 3MP image could quickly reduce to a 1MP 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 center 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 image back up and filling
in the blank spaces. Image quality is degraded and the greater the magnification, the more you
lose. A 3MP sensor might actually be using only 1MP at the center and "filling in" the other 2MP.
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 or three times magnification.
Also, be aware that the sensor is not the same size as a piece of 35MM film, so when you see the
focal length stated in mm like 38-115mm (3X) this is actually a more telephoto angle lens than
you would get in a 35MM camera. PC Photo Magazine list the conversion at approximately 5X. My
Olympus camera has a lens of 5.4mm - 16.2mm which they state is equivalent to 35mm-105mm on a
35MM camera which equals slightly wide angle to short (Portrait) telephoto for those not familiar
with 35MM 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 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 ($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 ($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 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 just 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, which slide into the camera. You purchase them by memory size, in Megabytes,
which range from 4Mb to 64Mb with the MicroDrive going up to 340Mb. These capacities are
increasing as I write this. Some Sony cameras still use a standard 3 1/2" floppy disk. These are
cheap but are limited to 1.4Mb 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 produces the largest file sizes but also the best pictures.
JPEG is a "Lossy" compression algorithm. This means that some information is thrown away forever
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 you can
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 neighbor has includes only 2Mb
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 a 8Mb
card. Using that as a guide I will reproduce part of a table (with their terms) from the camera I
own:
| Resolution | Compression | # of pictures |
| 1600x1200 | TIFF - Minimum | 1 |
| 1600x1200 | JPEG - Minimum | 5 |
| 1600x1200 | JPEG - Std | 16 * |
| 640x480 | JPEG - Fine | 32 |
| 640x480 | JPEG - Normal | 82 |
* This is the setting I use most often but I have to go back and Save-As with a higher level of
compression if I am sending the files over e-mail to keep the size at a reasonable level for a
dial-up download.
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 & whistle. You might be
carrying the camera all day on vacation so don't overbuy on size just to get a feature you may
never use. The box of my still camera says it will take video clips also. 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 only gives you 96 seconds with a 32Mb memory card
at 320X240 resolution. No 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 you 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 "guaranteed" a connection. The preferred
way is with USB. It is many times faster, almost every computer now supports USB, and you can
"hot-sinc" with USB, you don't have reboot to connect the camera as you probably do with a serial
connection. Even if your camera only has 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 3 1/2" floppies that
you can put the memory card into.
That is just about all I have room for this month. Next month we will get into more of the
special features that make the camera easier to use. I will also tell you which camera I
purchased and why. I welcome your input and questions for what I should include. ???
Digital Photography - Part 2
Last month, I tried to cover the more important considerations in purchasing and using a digital
camera. I will repeat here that 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 just like computers, technology advances daily (or is that
hourly?) and the 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 overbuy! 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 1MegaPixel, removable media (not floppy), and flash. A
3X zoom, TV out, USB and a LCD and Optical viewfinder are next on the list. Eliminate the zoom
and the Olympus Brio 100 or Hp 215 are good choices for $200-250. If you are really unsure and
just want to test the waters, try a JamCam or one of the $50 to $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, I 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 background. 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 an 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 sinc 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.) Also, red eye reduction flash or slow sinc features are desirable as you get more
experienced in creative photography.
Speed of taking pictures:
Many digital cameras take 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, be harder to find, or not be removable so 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 anyplace 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 of 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 gets going, many camera companies are starting to add in-camera features. These
include Close-up/Macro capabilities, Slide Show display of the pictures on thte 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 personally 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 also occupies memory so it cuts 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 www.cnet.com and
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 purchase decision. I have an
Olympus D-490. It is a 2.1MP camera with both 3X Optical Zoom plus 2X Digital Zoom, an Optical
view finder and a LCD, Removable media (Smart Media), Preview/review with Multiple & 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 $400.) This has be superceded 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 $500). My son uses an Olympus D-460 which
is almost identical to my D-490 but is only a 1.3MP 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.
For more information on the Tulsa Computer Society click here
Tulsa Computer Society 8/04/2001
Don Singleton, President