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Old Mar 28, 2003, 12:02 AM   #1
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Default Compressed size. what is this?

hi all,
i just bought a DX3900 Kodak.
Just wondering, there's this option in this camera.
a 3.1 Megapixel and a 3.1 Megapixel compressed.
3.1 Megapixel compressed saves the file using a much more smaller space.
is there any difference between this 2 functions?
pic quality?
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Old Mar 28, 2003, 12:18 AM   #2
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The compressed is probably in jpeg which is fine for everyday pics, but for really important ones, you will want uncompressed. In order to save space, jpeg files omit some of the picture data occasionally creating artifacts in the pics and more info is lost every time a pic is resaved in jpeg.
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Old Mar 28, 2003, 8:04 AM   #3
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Default Re: Compressed size. what is this?

Quote:
Originally Posted by nsw82
... a 3.1 Megapixel and a 3.1 Megapixel compressed.
3.1 Megapixel compressed saves the file using a much more smaller space....
How large is the "3.1 Megapixel" image? If it is about 9.3 MBytes you have a truely uncompressed image - one byte for each of the Red, Green, Blue values.

I don't think that camera has a true uncompressed save format. Likely what you are looking at is different degrees of compression. In general, you want to save your pictures in the format that puts the fewest pictures (largest size) on your card for the highest quality. Memory is cheap - get more of it. A lot more.

If you want to see the effect of compression, look at a high contrast area like a roof line against a white sky at high magnification. The JPEG artifacts will show up as 8x8 pixel blockiness. In many cases, that might not be important - it will only be important in the picture that you want to blow up to the largest possible size. One you didn't plan to make a large print when you took it, but now can't because you were trying to save memory space.
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