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Entries in RAW (2)

Sunday
Nov082009

JPG vs RAW

There are more and more of us moving from shooting JPG files to RAW files recently.  The supportive argument has been that the RAW file contains so much more information about the photograph which allows you to save a marginally exposed shot for example, which is true.

But here is another reason which resurfaced for me while Carla and I were working out how to resize a photograph in Photoshop Elements. (that discussion in saved in the forum).  This is what we discovered in the process.  If you use Elements you might open up a photograph and follow along.

The photograph that I had opened to work out the details of resizing was about 4.5 megs in size, not particularly big.  But when I brought it into Elements and went to practice resizing it, Elements said it was something like 28.5 megs in size. How could that be?  Well Elements was telling the actual size in memory after it had been uncompressed.  The JPG file format is what is known as a LOSSY file format, one amongst several, that do a tremendous amount of file comperssion when they are saved to disk. 28.5 mgs to 4.5 megs on disk is a big leap, something you don't see with your RAW files, they are what they are big.... big all the time.

JPGs standing on their own in most curcumstances are fine.  They are great for snapshots where little or no editing is going to take place and JPGs are for the most part are intended for the web. But a LOSSY file format goes under a lot of compression as we saw above and if you edit and save... then re-edit and save, each time information will be lost with each re-compression, as the name LOSSY implies.

There are several file formats that are called LOSSLESS. They do not compress or compress in a way that does not lose information. TIFF files are a good example of this as well as your camera's RAW files to name a few.

So don't turn away from JPG files, just use them in the right situation, for the right type of photographic work that you are doing at the time.

 

Wednesday
Sep302009

Adobe's DNG File Format

A couple of years ago I got into a conversation with my Uncle about Adobe's attempt to create a standard for digital photographic files. They call this new file format a Digital Negative (DNG). He felt strongly at the time that it was just an attempt and that there was significant resistance to making it a industry wide standard as a RAW file.

This isn't an issue when we use our "point and shoot" cameras. They for the most part save our photographs in JPG format.

One thing holding many photographers from moving to DNGs has been photographers trust. What if Adobe went away? Would our photographs be usable over time?

I understand that Adobe is in the process of licensing the DNG file format to the Open Source Community..... This means that software developers will always have access to the design details and can legitimately use it in software that they design. This is a BIG deal.

I've heard that many professional photographers are now moving their photographic libraries to DNGs. Why are they moving their photographic libraries to this new file format, what might be some of the advantages?

Portability was mentioned above, the ability to move photographs created by a camera to any system that understands the DNG file format. Remember too that a DNG file is considered to be a RAW file format but is not restricted to one camera manufacturer. There is no guarantee that the maker of your camera will be around. Big companies like GMC, Chrysler and Ford can go away rather quickly as we've seen.

One more reason that might be important. When working with RAW files in Aperture or Lightroom for example (photo editing and organizational tools for those that don't know), the photographs are not actually modified as you edit them. The attributes, the information about the changes that you have made, are held in associated files and the changes are applied to the photographs as you view them, export or print them. This is a feature that is great but what if you want to move yoru photographs? What about your edits and modifications? You can spend a lot of time tweaking photographs to loose that work.

In the DNGs changed attributes are embedded in the DNG files it self. There are no associated attribute files to worry about. You can not loose the changes, they come with each photograph.

One other interesting note. One Pro who produces a podcast mentioned his move to Lightroom away from Aperture. He loves Aperture but Adobe is like a huge "black hole" that bends the entire photographic industry toward Lightroom. He was constantly being asked questions about Lightroom, so he too had to move, it was his job at stake. This alone might well seal the question of DNG files for good.

We will see......... This certainly needs to be looked at more, there are always draw backs.