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Lion
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| Joined: | Thu Mar 6th, 2008 |
| Location: | Mississippi USA |
| Posts: | 25 |
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Posted: Tue Oct 21st, 2008 09:19 am |
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There are two different types of file compression algorithms.- Lossy
- Lossless
Lossy reduces the size of the file much more than lossless by discarding information that is invisible. The human eye can only see part of the information any given image file actually contains. By discarding the information that is unnecessary because of your eye's limitations, the file size is reduced significantly.
Lossless reduces the size of the file without losing image quality. The downside to lossless formats is that they are usually large files. If you want to retain the quality of the image and are not concerned with the size of the file this is the best choice.
Which is which?
(.jpg)
JPEG files which are by far the most common are lossy. This is the format your camera most likely saves files as. This is a good format to send via email or to post on the internet, because of it's smaller size. However, this is one of the worst formats for photo archival purposes. If the image is edited, saved and edited again the file degrades. Artifacts are also a problem with this format. They are spots, blocks or blemishes caused by the JPEG compression algorithm. The quality of the file can be chosen when saving a JPEG the higher the number the better quality. A lower number makes the file smaller but degrades the quality of the image, making it fuzzy.
(.png)
PNG files are the next generation GIF and are lossless. GIF files support 256 colors, making them poor choices for high resolution photos. The PNG format supports 16 million colors. This will be a larger file but is a better choice for editing pictures than the JPEG format. PNG files load faster/different than JPEG on the internet. Only newer browsers support this format but if you are on the internet you should be using an up to date browser. (If the update is not up to you, ask the person who owns the computer to update it for you.)
(.gif)
GIF files are limited to 256 colors but is also lossless. This is the standard format for images you see on the internet as buttons, logos, bullets, animations, cartoons and general web graphics. Most graphic style images are made with only a few colors so a more color capable format is not always necessary. Virtually all browsers (non-graphical based browsers being the exception) support this format.
(.bmp)
BMP files are Windows specific although most other Operating Systems have the capability to process any image format now. BMP files are uncompressed and are extremely large.
(.tiff, .tif)
TIFF files are the printing industry standard mostly because of their ability to handle different methods of print (machine and ink specific methods). They can be both lossy and lossless. If your camera can save in TIFF format, check to see if it is using the LZW compression algorithm (the standard) or equal, which is a lossless compression method. Web browsers usually hate this format.
(.raf, .rwz, .bay, .r3d, .ptx, .pef, .pxn, .cap, .tif, .iiq, .mef, .mos, .crw, .cr2, .orf, .nef, .nrw, .dng, .arw, .srf, .sr2, .k25, .kdc, .dcs, .x3f, there may be more...)
RAW files are usually lossless (some are nearly lossless) and are smaller than equal sized TIFF formats. Your graphic/photo editing software may not be compatible with this format and the algorithm used by your camera will determine the usability of this format. (there is no standard RAW format so two RAW files may not be compatible or comparable)With all that said, the RAW format (certain ones are better than others) is considered a Digital Negative, similar to a traditional film negative. The idea is that the RAW is to capture 100% of what the camera saw and record the data (flash, exposure, etc...) created at that instant. It's an unprocessed image that must be later converted to another format like a negative is converted to a photograph. When you take a JPEG photo with your camera it is first a RAW then is converted to a JPEG by the camera. The format is uncompressed with very little processing, hence the name RAW. It does take a lot longer than most to save and you can't rapid fire shots.
Summary
Taking Photos- Go with JPEG for photos if you want them fast and aren't worried about the quality.
- Go with TIFF if you are worried about the quality of the photo.
- Go with RAW if the format your camera shoots is a good one and you have the time to let it save and convert it later.
Sharing Photos- Go with JPEG when you need it small and are just sharing. (email, internet)
- Go with TIFF when you need detail and aren't worried about the size.
Graphics- PNG for lots of colors and quick loading.
- GIF for compatibility.
Archival- Any format that is lossless and suits your file size requirements.
This isn't an exhaustive list of formats, just the most common and most useful so far.
If I left anything out that you feel needs to be added, post it.
____________________
“All are lunatics, but he who can analyze his delusions is called a philosopher.”
~Ambrose Bierce
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dlaw
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| Joined: | Sun Jun 22nd, 2008 |
| Location: | Middle Tennessee |
| Posts: | 113 |
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Posted: Tue Oct 21st, 2008 11:35 am |
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Lion, thanks for the post explaining to those of us who are "technologically challenged" the difference between file formats.
Dave
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Squatchin'- it's not a passion--it's an obsession
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tennesseecherokee
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Posted: Sun Nov 30th, 2008 08:23 am |
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| Again, I'm kicking myself for apparently not looking as close as I should have ! As dlaw said, us "technologically impaired" folk need all the help we can get. LOL! I'll be the first to admit that I have not educated myself and done enough to stay abreast of everything regarding technology---as I should have. Thanks to you I am committed towards gaining more knowledge and hopefully understanding this subject much better. I would really like to know enough about audio and visual files and devices so that maybe someday I can help others as you have. Thanks again ! .......TnC.......
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We will be known forever by the tracks we leave behind.
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Lion
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| Joined: | Thu Mar 6th, 2008 |
| Location: | Mississippi USA |
| Posts: | 25 |
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Posted: Sun Nov 30th, 2008 08:54 am |
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You are very welcome and I'm glad I could help.
It gets more complicated (and interesting) such as embedding audio clips in TIFF images and marking your photo's in the field with real-time GPS coordinates. Technology is great as long as someone lets you know what to do with it. People are funny about it all, data and the transfer of data makes the modern world go 'round but no one takes the time to explain.
____________________
“All are lunatics, but he who can analyze his delusions is called a philosopher.”
~Ambrose Bierce
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tennesseecherokee
Member
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Posted: Sun Nov 30th, 2008 04:41 pm |
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| You hit the nail right on the head, Lion. It's not that it's so complicated. The hard part of it is just separating all the aspects and picking apart exactly what you will actually need to know or what will or will not be useful to your application. You explain things throughly and on a level that anyone that's interested can understand....TnC.....
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We will be known forever by the tracks we leave behind.
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