DIGITAL IMAGING SIG NOTES
–Gary S. Resnick
DIGITAL
IMAGING IS EXPLODING
Everyone seems to have or
want one…
Biggest innovation in
photography in over 100 years
Is a digital camera the
right choice for you? It may not be if
(a) you are intimidated by using a computer;
(b) you have difficulty
reading instruction books;
(c) you have difficulty reading and
understanding the small symbols on the menus on the camera display panel; or if
(d) you only take a few
rolls of film in a year.
However,
if you take lots of rolls of film, have lots of prints stored around the house,
and often leave a partially exposed roll of film in the camera because you
don’t want to develop just a few pictures, then you might be in the market for
a digital camera.
COST FACTORS: Digital cameras are getting cheaper
and better.
Film camera – costs to buy film, cost to develop, cost to make reprints, and another
trip to developer. Each print lying
around the house or in the trash costs you over a quarter. Lots of quarters add up to real money.
Digital camera – after initial purchase, pictures are free. Cost only if you wish to make
prints. At local stores you can choose
to print only the images you want for about a quarter each. No need for a photo
printer or photo paper unless you wish to do your own printing.
WAITING TIMES:
Film camera – must wait until film is developed.
If you wish copies, then another trip to the developer, another waiting
period
Digital camera – instant gratification, shoot a whole bunch of photos, keep what you
like, discard the rest, retake the ones that didn’t come out well. Copies are as simple as a few clicks of the
mouse on your printer.
CONVENIENCE: No waiting to send vacation or special event pictures to your friends
or family. Not limited to rolls of film
with 20 or 36 exposures. With a large
size memory card (more about this later) you can take hundreds of pictures and
e-mail them or print the ones you wish with your own computer and printer.
SOME BASICS
PIXELS: At the heart of every digital camera is an electronic sensor that records the
image. It is composed of millions of
picture elements called pixels. These do
the actual recording of the image in a series of microscopic electronic dots.
The greater the number of pixels, the sharper the image. 1,000,000 pixels + 1 megapixel. The highest quality film camera may take pictures with the equivalent of
12,000,000 pixels. The human eye has the
equivalent of 20 megapixels.
Digital camera capability
is measured in megapixels. If you see a
specification for a camera resolution that is 1600 x 1200, multiply these two
numbers together and you get 1,900,000 pixels.
This is a 2 megapixel camera.
The larger greater the
number of pixels, the greater the clarity of the image and the larger a
print that can be made from the image.
If you are going to just
e-mail pictures or view them on your computer screen or TV set, you could not
tell if the photo was taken with a 2 megapixel or a 5 megapixel camera. It would only become apparent if you were
trying to enlarge and print the picture.
ZOOM LENSES: 2 TYPES – Optical and Digital
Optical zoom lenses
actually magnify the image . You can
shoot telephoto or wide angle photos with no loss of quality. A 4X optical zoom lens has the zoom range
from about 34mm – 140mm.
Digital zoom is an
electronic trick that will magnify the center of the field of view, but
decrease the quality of the image. It
reduces the total number of pixels used to record the image. If you are looking for a camera, choose one
with an optical zoom lens in addition to the advertised digital zoom.
MEMORY CARDS: These record the images. Different manufacturers use different types
and they are not interchangeable. Most
digital cameras are sold with 16 or 32 mb memory cards. A 256 mb card (about $40 or so) allows you to
take several hundred pictures.
Can be reused. Transfer your pictures to your computer,
delete the images from the memory card, start all over again.
VIEW FINDERS: 2 Types – LCD and optical (the optical viewfinder is
that little lens on the back of your present camera).
LCD – liquid crystal
display –acts like a miniature computer
screen. Allows you to see image and to
see what you have just recorded. Uses a
lot of battery power and may be difficult to see in bright sunlight.
Optical – just like that on
the camera you are now using. Not a
through the lens system and may not show the true field of view. May end up cutting off heads, arms or legs.
CHOOSING
A CAMERA
Three major categories we
might choose: entry level, mid-range and prosumer. (term comes from combining
professional and consumer). The prosumer
cameras of 2 -3 years ago are now essentially in the mid-range both price wise
and feature wise.
ENTRY LEVEL: This might be the camera of choice for folks who look at
photography as a way of recording memorable events. These cameras have relatively few “bells and
whistles”. May have
2 – 3 megapixels , small LCD display, weak flash
unit, small view finder, fairly small memory card. May not have an optical zoom. Cost $150-$200. Some on sale for about $100. Can make prints up to 3”x5” or 4”x6”. It may even take very short, low quality
movies.
MID RANGE: Have a better lens system, 4-5
megapixels, a zoom 3X-4X optical zoom lens, high flash output, larger LCD
viewfinder, controls that will allow the user to change shutter speed,
aperture, longer movie sequences, and several other features and controls that
will be covered later. Costs $300-$400.
Capable of making 5”X7” and even 8”x10” enlargements.
PROSUMER: Up to 5-6 megapixels (some
up to 8 megapixels), high quality zoom lens usually 4X – 6X, but may be greater, an optical viewfinder
coupled to LCD for ease of focusing, manual control over myriads of features. (the instruction book that came with my
camera is 205 pages long – all in English)
Do I know how all the capabilities of my camera – no way) Can take longer movies, enlarge photo up to
11”x14”. Costs now in the $400-$600
range.
SPECIALITY CAMERAS: cell phone cameras are not
very useful except for sending pictures from 1 cell phone to another. Some newer cell phones have higher quality
digital cameras, but most are low quality (less than 1 megapixel).
BEFORE YOU BUY - Determine your needs in advance. Don’t become a casualty to the megapixel
war. More is not always better. If your major interest is taking pictures of
grandkids,
e-mailing
, and/or making prints 4X6” or 5x7” prints a
3
megapixel camera will work fine. For an
8x10” print, you might opt for a 4 megapixel camera. A 3
megapixel camera that takes pictures well in all light conditions, may be a
better a choice than a 5 megapixel camera that is difficult to focus in low
light conditions.
If
you take close-ups or pictures of flowers, you might wish to look for a camera
that has a macro focus mode. If you do a
lot of hiking, battery life may be a more important consideration than the
number of pixels. You need to determine
how you plan to use your camera before you make a decision. Just because a camera has all the latest
bells and whistles doesn’t mean it is the best for you.
Go
to stores like
BATTERIES – If your camera uses
disposable AA batteries, they may last less than ½ hour. Thus rechargeable batteries are a much better
choice. Get a good battery charger and
carry a couple of sets of rechargeable batteries with you when you are planning
to take lots of pictures. (Keep them
charged) Nickel hydride batteries are
much better than nickel cadmium batteries.
Some cameras take special lithium ion batteries. They are much more expensive, but last
longer.
OTHER CONSIDERATIONS - Whether the following are important to you might be factors to
consider prior to choosing a particular digital camera. The greater number of
features you might find necessary, the higher the cost of the camera.
SHUTTER LAG/BURST RATE – How great the time delay
is between when you snap the shutter and the image is being “written” to the
image file. Smaller delays are better so
there is less lag times between pictures.
Good cameras should have a burst rate of 1 – 2 images per second.
COMPRESSION/RESOLUTION - This is a measure of how accurately the image
is recorded with the least loss of color range and sharpness. Cameras can normally store the image as JPEG
(Joint Photo Experts Group) or TIFF (Tagged Image File Format). TIFF files are much larger. JPEG better for sending e-mail photos.
Compression might be listed as superfine, fine and normal. Resolution as large, medium and small.
AUTO EXPOSURE BRACKETING – Allows the user to take 3
different exposures of the same shot to insure the picture will be properly
exposed.
MOVIE MODE – The ability of the camera to take a brief
movie sequence. Quality can range from
poor to very good – time of movie can be from 15 seconds to as long as several
minutes depending upon the camera model.
STITCH MODE – This feature enables you to
shoot multiple images and then put them together later into a panoramic
photograph.
LENS QUALITY – Expect a lens with an f
stop of f/2.8 in a good quality camera.
Expect about f/3.5 in a less expensive model.
I
chose a model with an f/2.0 lens so I can shoot in lower light without a flash.
ADJUSTABLE SHUTTER SPEED - Should have settings to
1/1000 or 1/2000 of a second for action photos.
There should also be a range of slow shutter speeds for longer possible
exposures. At least a 1 second
delay. Can be as long as an 8 -15 second
delay for exposures taken on a tripod at night.
ADJUSTABLE ISO SETTINGS – Similar to choosing film
of different speeds for different conditions. (might range from ISO equivalent
of 50 – 400). ISO of 150 is fairly
normal.
ADJUSTABLE APERTURE
SETTINGS –
Enables you to select landscape, portrait or macro settings for different depth
of field choices.
ADJUSTABLE PHOTO EFFECTS – Enables you to select
degree of sharpness or emphasize color saturation and contrast.
WHITE BALANCE CONTROL – Controls how the camera
“sees” light from different light sources. Might be adjustable for daylight,
cloudy days, tungsten or fluorescent light sources.
SPOT METERING – Enables you to select the
“spot” on your image that you wish to have the light meter read.
CAMERA SIZE – I opted to buy a larger
camera. I have big hands. My wife has a much smaller camera that she keeps in
her purse with some extra batteries.
Guess who always has a camera ready when the opportunity provides and
whose is sitting at home. There is a
great selection of compact cameras out there.
Find the one you like and enjoy the advantages of digital photography.
WHERE TO BUY A CAMERA – That is the next
question. After all your research you
should decide on a brand and model. You
can then price compare at the following web sites:
www.pricegrabber.com (over 60 dealers listed)
www.CNetshopper.com (lists over 50
dealers)
www.yahoo.com
(lists about 20 dealers)
If
you decide to buy over the net, be very cautious. Prices may look to be too good to be
true. Many of the “deals” offered may be
“grey market” merchandise. These cameras
are bought cheaply overseas and do not offer a
Also
be wary of buying from one of the dealers listed on the above sites. Check out their customer satisfaction
record. It may be wiser to do business
with a local firm. One excellent source
is Precision Camera in
CONFUSED????
Go
to the computer club website: www.sctxcompclub.org
Look
at the Digital Camera SIG portion of the website, check out the camera inventory section. If there is a club member using the type of
camera you have researched, call the person, ask questions.
Also,
look at the section of the web site called on-line
resources.
Do
some further research.
Good
sources for professional reviews and information can be found at:
Buy
the camera you have researched, read the manual. Take the Digital Camera 101 class.
Take
lots of pictures.
ENJOY!!!