Backing up PEF Files

To ensure future compatibility I'm thinking maybe I should back up some of my old PEF files to another format but should I use TIFF or DNG? It's been suggested to me that DNG may not be the way to go for quality reasons - something about loosing some information during conversion?! Any thoughts on this guys?

DNG will be your best bet as in the future better RAW converters may get more info out of the file than at present (so I've read). TIFF will never die out but DNG is the standard RAW file so it's safe to say it's going to around forever.

Equivalent DNG files are generally a lot smaller too. My K20D DNGs are usually around 23MB, whil an equivelent Tiff is around 70Mb.

I have always shot DNG rather than PEF. I can't imagine there' be any quality loss. I always thought the conversion was more a mater of format rather than any kind of compression?

The raw file is the digital negative so it would make sense to stay in that format for archiving instead of fixing into bitmap format like TIFF.

I see that Adobe do a DNG converter program which converts various formats (inc PEF) to DNG, although it's a massive 50MB!
link

Massive?? What are you running? A ZX Spectrum?

Most of my TIFFs are bigger than that.


Although I did have a 20Mb Hard Drive once

Hi smeggy,

I meant that it seemd big for a conversion program. Some of my linux systems were 50MB in total. I sometimes use puppy linux and it's currently 140MB for a whole operating system!

The one thing to bear in mind though is that (at least according to the font of all human knowledge) the DNG conversion process doesn't preserve 100% of the original image for some RAW formats.

Whatever the truth of that, shooting in PEF and then converting to DNG is probably a better option than shooting in DNG: on the K20D at least (this may have changed on later models) PEF files are [losslessly] compressed while DNG files are not - leading to higher file sizes (whereas the Adobe converter will apply lossless compression to its DNG files).

Remember this one :
Years ago there was a QNX demo on a 1.44 MByte floppy; included a browser and an email client in a graphical environment.

Luckily the DNGs on the K-7 and K-5 are compressed to a similar size to the PEFs. The size is what stopped me using DNG on the K20D.

I know I can shoot one and find out, but from memory how big is a K20D PEF?

I guess in that case it must seem huge.

I'm used to huge bloat from Windows, Adobe, etc,etc

DNG will not lose quality over PEF files. In fact, DNG due to being a universal format, has more options in the meta data areas over 'branded' RAW files. Also, any Raw file conversion will not change data as it is only a profile. Think of DNG as more of a 'wrapper' that wraps around existing 'branded' RAW files to ensure uniformity. Very much in the same way that AVI is a 'wrapper' in video. Within the AVI file type are many different codecs that will now play on different software as it is correctly 'indexed'.

DNG simply sets out the existing RAW data in a uniform standardised file and with enhanced meta data capabilities, is more stable for the future demands of camera and shot information.

Just to be safe backup as JPG files as well. There's no guarantee that Operating Systems in the future will run old programs needed to read DNG and PEF and you may also need a license.

In a few years (when my current Panasonic drives die) I won't be able to read my Cartridge DVD-RAM backup disks because readers no longer take the cartridges. I'll have to break them open and carefully handle the double sided 9.4GB disks