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Techno Page
- By Harendra Alwis
Email:
technopage_lk@yahoo.com
Digital cameras:
Go for the best
Read
this before you buy your digital camera.
Digital cameras
are in fashion these days, but it is easy to get lost in their digital
world if you are not up-to-date with the features they offer and
what it means to you as the user. Here are a few tips to make your
choice both informed and wise.
Mega-pixels
(MP):
This number (it is a number... if you look carefully, you will
understand that mega means 'million') is simply the number of discreet
dots that will be combined to make up a single picture (so 2 mega-pixels
means two million dots would make up each picture). The more the
merrier because the higher the number of dots, the more detail you
would capture, but if the decision rests on need and price, then
here are a few guidelines;
1MP: Good for
computer use but not for printing.
2MP: Good for about 5x7 prints but not for any editing.
3MP: Good for about 11x14 prints (or 8x10s and below with editing)
4MP+: Good for Very large prints (or 8x10s and below with heavy
editing)
Zoom: Optical zoom is using the actual lens to zoom like a real
camera; digital zoom uses software interpolation to blow the images
up, reducing image quality. Optical is a must. Most cameras have
a 3x optical lens.
Lens:
The lens's Aperture rating will help give you an idea as to
what lighting the camera can be used in. Digital cameras are fairly
inefficient with light relative to film cameras (the camera's CCD
sensor is technically only 33% efficient), and thus a wider lens
aperture can really make a difference when shooting indoors with
poor lighting.
Memory:
There are five main memory formats you may have to look into:
CompactFlash: used in Canon, Nikon, HP, Minolta, and Kodak cameras.
Can be expanded anywhere from 8MB to 1GB. Higher end cameras feature
a Type II CF slot that can accommodate an IBM Microdrive. This is
the only memory card format where brand really matters as CF cards
have the memory controller integrated, and this can vary in speed
from card to card and brand to brand.
SmartMedia:
Olympus, Fuji, and Toshiba cameras. Expandable to 128MB but not
all models can take larger cards. This is the oldest standard and
has been replaced by the newer XD cards. The memory controller is
built into the device, not the card, which makes the card easier
to produce as well as making brand more or less irrelevant. The
downside is many older SM devices cannot use larger SM cards.
Multimedia
and Secure Digital:
An ultra-compact memory card standard created by Scandisk.
Much Smaller than CompactFlash or SmartMedia and though Multimedia
is slightly older and only goes to 128MB, Secure Digital goes up
to 1GB. Both of these cards will work in the same slots, though
the newer Secure Digital cards can be up to 5 times faster. However,
they also implement Digital Rights Management, though there have
not been many products taking advantage (or disadvantage) of this
feature yet. These cards are used in almost all Palm OS PDAs. They
are also very common in MP3 players.
XD:
Used on the newest Olympus and Fuji cameras. Currently available
in capacities up to 128MB, with 256MB and 512Mb cards expected to
be available very soon. XD is the physically smallest card format,
approximately 2/3 of the size of an Secure Digital card.
Memory Stick:
Sony cameras use this memory format. Readily available in sizes
up to 128MB. Typically this is a little more expensive per megabyte
than the previous formats. The new 256MB Memory stick is incompatible
with all but the very latest models. Some of the new 256MB memory
sticks feature a switch that allows you to use it in a segmented
2 x 128MB format.
Image Size
1.3MP images are approximately 300KB in size (These sizes can
vary quite a bit, as both the compression ratio in the camera and
the subject affects file size.)
2.1MP images are approximately 1MB in size
3.3MP images are approximately 2MB in size
4MP Images are approximately 2.5 to 3MB in size
Images taken in TIFF (uncompressed) format are usually 4 to 8 times
as large as the corresponding JPG file.
Batteries:
AAs: Most digital cameras will use either 2 or 4 AA size batteries.
You have a few options for these:
Alkaline:
Normal alkaline AA batteries will last for about 20 minutes
of continuous use in a camera. Not a great idea unless you can't
afford anything else.
Lithium:
Long life disposables. A set of four lasts for about 4 to 5
hours of continuous use (about a long day of picture taking).
Nickel Metal-Hydride:
These rechargeable batteries that replaced the older NiCADs,
give about 2 to 3 hours of continuous usage on a set of 4.
Lithium-Ion:
Mainly used in high end cameras. The same technology is used
in current camcorder and laptop batteries. Best charge per size.
Durations vary from 1 hour for smaller batteries to 3+ hours for
larger ones. Prices also vary accordingly.
Other Features:
Manual Control: Available mostly in professional models, this
feature allows you to manually set the aperture, shutter speed,
and sometimes focus range of the camera. This is useful for shooting
in low light or when the subject is moving fast. These cameras also
usually have programmed modes, where the user specifies one of the
settings and the camera determines everything else.
Movie Mode:
Allows you to record low-resolution (320x240 pixels) video
onto your camera's memory card. Record time varies by model, usually
ranging from 15 seconds to the limit of the memory card. Most cameras
record in a proprietary AVI codec. Sony cameras record in standard
MPEG format with no limitations on length.
Threaded
Lens:
Some high-end cameras will have a threaded lens. This allows
you to add extensions and/or filters to the camera. So far, there
aren't any consumer-level digital cameras with interchangeable lenses,
so this is the next best thing.
References: I-sourcenet, Sony, Nikon, Olympus, Kodak, Fuji, C-net
More dial-up
misery
I
am an Internet subscriber from Kandy. I surf the Internet
on a daily basis and I experience the dial up misery very often.
I surf the Internet for more than three hours a day and it is always
very frustrating when your connection is disconnected while chatting
with a friend or while a download is in progress. During the three
hours I surf, my Internet connection disconnects about six times
on average and the irony is that my Internet Service Provider has
given me three dial-up phone numbers to connect from but two of
them never work!
It is very
difficult to even connect to the Internet as I have to keep trying
many times and over a considerable period of time simply to connect
to the Internet.
The bottom-line
is that Internet services in Sri Lanka are of very poor quality
and speed and leaves much to be desired. There is a reasonable demand
for high-speed Internet connections and better services. Why can't
we have a faster Internet speeds?
- Theekshana Jayakody
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