6 Replies Latest reply on Aug 25, 2014 5:27 PM by areohbee

    how does lightroom 4 deal with lossless compressed raw files

    Rick Hopson

      how does lightroom 4 deal with lossless compressed raw files

        • 1. Re: how does lightroom 4 deal with lossless compressed raw files
          dj_paige Level 9

          "Deal with"? It knows how to use the files, but if you want more information, you need to be more specific about what you are asking.

          • 2. Re: how does lightroom 4 deal with lossless compressed raw files
            elie-d Level 4

            It decompresses them, reads them and utilizes the data they contain.

            • 3. Re: how does lightroom 4 deal with lossless compressed raw files
              Rick Hopson Level 1

               

              Ok, sorry about the vague question.  My concern is centered around a new camera purchase ( Nikon D810 ) which produces huge files.  I shoot in RAW and never use lossless compression only uncompressed RAW because of my conservative nature .  But now it looks like I will be using Lossless compressed to help deal with the file size.  So the question was based on fears of data lost.  Thanks for the replies, and they confirm what I already suspected. So now I can feel confident using lossless compression.


              Thanks

               

              • 4. Re: how does lightroom 4 deal with lossless compressed raw files
                areohbee Level 5

                I don't know why uncompressed is even an option. Always compress your raw data, unless you have a good reason not to (I'm not even sure there ever is one anymore, for normal users anyway) - lossless means "no loss" - none... original is reconstituted bit-for-bit when decompressed...

                 

                Maybe if you were decompressing on a computer which didn't have a math processor or something, you might want them uncompressed, but modern CPUs can decompress faster than they can read from disk, so lossy compression is:

                 

                * faster

                * smaller

                 

                i.e. there is NO down side.

                 

                I'd love for anybody to point out real scenarios where that is wrong.

                 

                Rob

                • 5. Re: how does lightroom 4 deal with lossless compressed raw files
                  Dave Merchant MVP & Adobe Community Professional

                  Rob Cole wrote:

                   

                  I don't know why uncompressed is even an option.

                  Nikon has always offered the choice to save NEFs in compressed or uncompressed versions. Their compression is "visually lossless", not mathematically lossless - so there is a microscopic amount of data being removed through curve shaping at the extremes, though for all practical purposes nobody would ever be able to tell (you'd need to shoot a pixel-perfect pair of images and run a difference layer comparison in Photoshop, I've yet to see anyone achieve that). Some astro people shoot UCRAW because they want every stray 13th or 14th bit to be 'correct', but Nikon's argument for having both versions is all about burst speed - depending on the body and card you're using, UCRAW can give a significantly better (or worse) cycle time.

                  • 6. Re: how does lightroom 4 deal with lossless compressed raw files
                    areohbee Level 5

                    Dave Merchant wrote:

                     

                    Their compression is "visually lossless", not mathematically lossless.

                    Thanks Dave - I stand corrected (I thought it was mathematically lossless).

                     

                    Still, as you said, for most practical photography purposes, visually lossless is equivalent if not equal to mathematically lossless, image-quality-wise.

                     

                    I can see how camera hardware & firmware design could influence burst performance depending on compression scheme - thanks again.

                     

                    Cheers,

                    Rob