Re: DPI and PPI

In article <1152749600.876992.296850@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
mactier@xxxxxxxxxx says...


Can one change the camera setting of how the images are compressed? Or
would that be a software issue? I just noticed now that some of the
2048 x 1538 images that I received are compressed to 500K and I'm
wondering how that happened?


It possibly may be image content, as per the other message. This would be
true only if it was exceptional in the large degree of blank space all the
same color.

But yes, digital camera menus have two "size" settings.

One is the size in image dimensions, like 2048x1536 pixels.
One is the size in JPG Compression, called Quality.
Both affect file size.

This gets a bit confusing in the chart to show you how many images will
fit on your memory card, but it is about the combination of two
properties, dimension in pixels, and JPG Quality.

The largest image (pixels) at the highest Quality JPG will be the largest
image file. It is of course the best one. Large JPG size is a good
thing, not a bad thing.

If you have more pixels than your use needs, you can decrease the image
size. Maybe you only print snapshots and dont crop much, and dont need
more than 3 megapixels. However then the problem is that rare special
great image when you really want a much larger print - it won't be big
enough to print large.

If you dont feel you need the maximum quality, you can lower the JPG
Quality setting for a smaller file. Opinion, but this might be acceptable
for snapshots when space is tight, but is not acceptable for the rare
special images. My own opinion is that the largest JPG is not too much
Quality.

JPG is lower quality due to the visible JPG artifacts that it adds, which
spoil the picture in some degree. JPG is Worse at lower quality, Better
at higher quality. If you ever have need to edit and SAVE the image again
(as JPG), then you get a second set of artifacts, each time you save it
again as JPG. So best not to have to do that (save again as JPG), at
least never more than once more, but when you do, it is also best to use
High Quality every time.

Quality is really what it is all about.

--
Wayne
http://www.scantips.com "A few scanning tips"

.

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