Re: PHOTO: digital images
Dennis Kramb wrote:
>
[snip]
>
> Suuuure, I'll give it a whirl, but I'll warn you that I'm not a
> techno-weenie. <G> My digital camera has 3 settings--low, medium, and
> high. On the low setting you can get about 100 images per memory
> card...medium about 40...and high about 15. (Rough estimates here.)
[snip]
Well more two cents from a techie type.
One of the things I have not heard about here is compression. Now I can
only speak from the experience I have had with our Sony Mavica. But I
suspect they apply to most others as well.
A couple of basics.
Cameras have a fixed number of pixels, that is LCD (Liquid Crystal
Display) crystals. These are the things that convert light into
electronic signals. I am not sure how they divide the light into its
three components (Red, Green, Blue). Could be multiple crystals (one
each for each color) or electronically - for the purposes fo this
disscussion, it does not matter. Each crystal is equivalent to a pixel
on your computer screen. They are always the same size (in a given
camersa), they don't vary.
So lets say that you are interested in a particular petal of a flower.
If you take a picture in which the petal takes up one quarter of the
width of the picture in the view finder, you will use one quarter of the
pixels available. If you take a picture in which the petal takes up
three quarters of the width of the picture in the view finder, you will
use three quarters of the pixels available, and so forth. So, as with
regular film, the closer you are to the desired subject the more detail
you will be able to see (assuming everything is in focus).
Now on my camera I can take two sizes of picture as designated by the
number of pixels used horizontally and vertically. Large is 1074 X 780
pixels and small is 640 X 480. In the latter case the camera just uses
fewer pixels than are available.
The camera also gives me several "Recording" modes. Bitmap, Fine and
Standard. Bitmap uses no jpeg compression and I get one picture per
floppy disk. Fine quality uses a low compression algorithm (so the
reconstructed picture is better). Standard uses a high compression
algorithm (the reconstructed picture is less good). I suspect that
Dennis' camera settings of Low, Med, and High correspond to High, Med,
and Low compression ratios respectively, and that in his Low setting the
high compression ratio results in a certain amount of picture quality loss.
The smaller the picture, and the higher the compression ratio, the more
pictures you will get in a given storage space, but the lower the
quality of the picture.
Hope that helps s little.
John | "There be dragons here"
| Annotation used by ancient cartographers
| to indicate the edge of the known world.
________________________________________________
USDA zone 8/9 (coastal, bay)
Fremont, California, USA
Visit my website at:
http://members.home.net/jijones
President, Westbay Iris Society
Director, Region 14 of the AIS
Chairman, AIS Committee for Electronic Member Services
Subscribe to iris-talk at:
http://www.onelist.com/subscribe/iris-talk
Archives at: http://www.mallorn.com/lists/iris-talk/
Subscribe to iris-photos at:
http://www.onelist.com/subscribe/iris-photos
Archives at:http://www.mallorn.com/lists/iris-photos/
________________________________________________
------------------------------------------------------------------------
Good friends, school spirit, hair-dos you'd like to forget.
Classmates.com has them all. And with 4.4 million alumni already
registered, there's a good chance you'll find your friends here:
http://click.egroups.com/1/2885/0/_/486170/_/956471165/
------------------------------------------------------------------------
