[Leica] convert to DNG? sweet barking cheese! NO!

[firkin at ncable.net.au (Alastair Firkin)]

My tiff to dng files are smaller than the original tiff file but I'm  
not sure why ;-)

On 05/11/2006, at 9:40, Kyle Cassidy wrote:

>
> alistar sed:
>
>> I have noticed a "convert to DNG" function in Lightroom: If I convert
>> my scanned tiff files to DNG I gain 30 megs over the 130meg tiff
>> file: do I "lose" anything?
>
>
> if you convert a TIF to a DNG you don't get "extra" information.  
> you just get a bigger file.  it's like taking a 35mm negative,  
> making a 4x6 print, and then photographing that print with a 4x5  
> camera -- you haven't added data to your image, you've just made it  
> bigger.
>
> the only thing you should convert to DNG is your camera's RAW files.
>
> DNG is Adobe's "Digital NeGative" format. it's a type of RAW.
>
> many camera manufacturers have a propriatary RAW format (such as  
> nikon's NEF format). DNG is an open source raw file. one reason to  
> convert your NEF to DNG files is that some day NEF files may go  
> away but the ability to read a DNG file will, theoretically be  
> around longer because the standard is open. DNG files are also  
> compressed, so they're smaller than NEF files.
>
> RAW files are lossless.
> TIF files are lossless
> jpeg files are lossey
>
> there are many other file formats which are also lossless:
>
> .gif, .psd, and .png, notably.
>
> converting a DNG to a TIF is lossy, you throw out some information  
> and say "this is what i want to use in my image" -- you'll convert  
> to tif or jpeg eventually, and you don't want ALL the information  
> in your image, you WANT to get rid of it at some point (though not  
> forever, so keep your RAW files backed up in case you some day want  
> to dig a license plate out of the shadows somewhere).
>
> so, again, if you convert a TIF to a DNG you don't get "extra"  
> information. you just get a bigger file.  it's like taking a 35mm  
> negative, making a 4x6 print, and then photographing that print  
> with a 4x5 camera -- you haven't added data to your image, you've  
> just made it bigger.
>
> hope this helps.
>
> keep photographing that breakfast, it'll get cold eventually,
>
> kc
>
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