A couple of questions

[aquakiwi]

Having heard Jpegs degrade with use and having a camera that only shoots Jpeg, is it
worthwhile down loading images and changing to Tiff format before saving on CD or
harddrive? Second question, I understand the term Chromatic Abberation is caused by a dark object being surrounded by highlights, Is there a way to avoid it other than not taking those sort of shots? I have a couple of shots where it is quite apparent (the stingray on this post is one).

 

[Stryker]

I would not worry too much about the JPEG issue.... JPEG is nothing more than a file compression type... you do lose SOME quality when you take these kind of pictures versus shooting directly into TIFF or RAW format....

What kinds of photography do you want to do? is it just for pleasure and making memories? if so I wouldnt worry about it too much....

 

[Chad_Ordelheide]

A lot of programs will ask you how much you want them compressed when you Re-Save them. Mine has a default of 85% of original quality, which I usually change to 100% since I don't lack disk space. That may help with your degradation issue?

 

[diversteve]

Having heard Jpegs degrade with use and having a camera that only shoots Jpeg, is it
worthwhile down loading images and changing to Tiff format before saving on CD or
harddrive?

I would, everytime you re-save a jpeg you will lose a little quality as it's what is known as a lossy compression format. Tiff format is a lossless format so no compression is applied. Anyone who's ever done print work does this automatically, I learned it from a graphic designer who designs art catalogs.

For the best quality, turn off LZW or any other compression in your .tif save options also.

 

[ChillyWaters]

For the best quality, turn off LZW or any other compression in your .tif save options also.

??? Isn't LZW lossless compression? Thus, your file would just be smaller, but no quality would be lost.

- ChillyWaters

 

[alcina]

If you use Photoshop, you can also save in psd format - much smaller than tiff.

I always Save As .psd any photo I open...then I only work on the copy and the original gets tucked away safely.

 

[diversteve]

??? Isn't LZW lossless compression? Thus, your file would just be smaller, but no quality would be lost.

- ChillyWaters

I'm not sure, but anything with the word compression in it seems to me to have the potential to lose data. It's probably an insignificant amount of loss if there is any, I seem to remember that LZW compression is also used on data files - isn't it the basis for .zip archives? Given that most people aren't too concerned about filesizes with the prices of harddrives lately, it only takes one click to turn it off - your call...

 

[ChillyWaters]

I'm not sure, but anything with the word compression in it seems to me to have the potential to lose data.

Not to get too far off topic, but that is FAR from the truth.

It's probably an insignificant amount of loss if there is any, I seem to remember that LZW compression is also used on data files - isn't it the basis for .zip archives?

Do you think people zip files with the realization they may lose data??? NOPE!

Given that most people aren't too concerned about filesizes with the prices of harddrives lately, it only takes one click to turn it off - your call...

Not true. Imagine keeping all your photos without compression! For the avid photographer, that would add up in a REAL hurry.

My suggestion. Turn on lossless compression. You have nothing to lose.

- ChillyWaters

 

[alcina]

I keep all my images without compression, FWIW. I also keep several versions of many shots.

I have two big hard drives plus an external. As they fill, I'll add another. Everything is also backed up onto DVDs and/or CDs.

 

[hdtran]

I'm not sure, but anything with the word compression in it seems to me to have the potential to lose data. It's probably an insignificant amount of loss if there is any, I seem to remember that LZW compression is also used on data files - isn't it the basis for .zip archives? Given that most people aren't too concerned about filesizes with the prices of harddrives lately, it only takes one click to turn it off - your call...

\begin{Geek Alert}

There's lossless and lossy compression. There's also compression speed & compression ratio. LZW (Lempel, Ziv, Somebody) is a lossless algorithm.

TIFF files don't compress very well*. If your camera shot TIFF but not RAW, TIFF is actually a raw bitmap format. Most new cameras which offer a raw format offer their own format, rather than TIFF (which is an open format).

If you take a JPEG and convert to TIFF, you're not gaining anything. If you take a JPEG and resize to a different JPEG, you've just lost a bit of data. JPEG (or JPG) is a user-adjustable lossy compression method which works quite well for "normal" photos (pictures, not text, for example). JPEGs are fast to compress and have a very high compression ratio. They take advantage that most color images have relatively smooth transitions between colors, among other things.

*The reason most TIFF files don't compress very well is because they've already been compressed!

\end{Geek Alert}

I hope I didn't put anyone to sleep!