Tuesday, June 22, 2010

File Formats... Which one do I use?

You're probably aware that your DSLR camera provides you the option to record your images to the storage card in one of a variety of file formats.  The two most common types are JPG and RAW.  Most of us know about JPG - its more or less the "universal" format for sharing images.  In other words, pretty much any computer on the planet is capable of displaying a JPG image without installing additional software.  So why would you want to record your photos in anything other than JPG? Well, there are probably a few reasons but the most important to understand is that RAW files contain more color and detail information about the scene than JPG does. What does that mean for you?  For example, let's say you took a picture and it's dark (underexposed) or too bright (overexposed).  If the image was captured in RAW format (Nikon's RAW format produces NEF files), there is additional data stored within that file that will allow you to either lighten it up and recover details from the shadow areas or darken it to recover blown out areas of the image.
Remember these two images from the "Checking Exposure" post?

Here's a little secret - its the same shot modified in Adobe Lightroom 3! Because the file was captured using the RAW format (NEF), I was able to actually change the exposure setting when processing the photo rather than when taking the photo.  If you commit to capturing your photographs using the RAW format, you will put yourself in a much better position to save images that "could have been" simply by adjusting them in post processing (watch for future posts).  In fact I shoot exclusively using the RAW format with two exceptions:
  1. When shooting in "burst mode" and its critical to capture as many shots as possible.  JPG comes in handy here because the file sizes are slightly smaller which means they can offload from the internal camera memory to your storage card faster, and
  2. When I'm low on storage space and have run out of memory cards.  Again, JPG files are smaller and will allow you to store more on a single card.  They're smaller, though, because they don't hold as much information as we previously discussed.
"But if I'm at the family picnic taking pictures using RAW and Uncle Bob wants me to copy those images to his laptop, he can't view RAW images.  What do I do?".  Most DSLRs allow you to save a copy of a RAW file to a JPG using a utility right on the camera.  Then you can offload the JPG versions for Uncle Bob.
Until next time, keep click'n.


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