Do you convert NEF to DNG?

Started May 22, 2012 | Discussions thread
jtan163 Senior Member • Posts: 2,265
Re: Do you convert NEF to DNG?

konoplya wrote:

if you do, for what reason other than to reduce file size?

also, is any information lost during the conversion or not? i mean image information, not metadata etc.

thank you in advance.

This subject was recently beaten to near death in the M43 forum if anyone wants to see:

One reason I would suggest DNG is that apparently DNG code in Lightroom 4.x can take advantage of multiple CPUs. I got that from a Kelby training video - I think a D-Town episode.

So if you have a multi core CPU you may see speed increases in processing.

But the main reason I would recomend DNG is archiving if you care about your images and want to be able to access them in say 30 years time.

Let me be clear I don't DNG most of my images. But most of my images are not really worth keeping.
The ones I care about I DNG.

If your images are worth keeping, then I'd DNG them.
You're not DNG'ing them so you can open them in 3 years time.
DNG is insurance against the medium to long term possibility of format obsolescence.

Despite what some people think formats can and have become obsolete and governments and academics are quite concerned about format obsolescence - it is a fairly new problem and one who's magnitude is increasing daily.

For example, who can read a visicalc file on an Apple II 5.25inch floppy?

My guess is not many people, but not that long ago Apple II's were probably the most widely used PCs around and Visicalc was the market leading spreadsheet.

That was only ~30 years ago. Who's gonna be alive in 30 years? Many of you, I would guess. Will you want to see your photos? Probably, I'd guess.

I will admit that it is unlikely that formats that we are using today will be totally unreadable in say 5 years time.

But in 20, 30 , 40 years? Yes I reckon there is a decent chance that at least some of them might be effectively impossible for an aging photographer to read.

And even if your format(s) does not go away there is a fair chance that they may become prohibitively expensive to read for the average user and maybe even more so for a pro with a few hundred thousand files to convert.

Both file and media format obsolescence is a real problem.

Governments and academia are spending money trying to work out standards, solutions and risk mitigation strategies.

But don't take my word for the fact that file obsolescence is a real problem do some research - here are some links:

Here's an article from an Australian academic organisation that is intended to assist people in choosing good strategies for keeping their data available.

Here's an article about a UK project that is trying to address the problem that some people seems to think is a non issue.

Assuming they finish there is no guarantee your version of RAW will be supported, that you would have access to the software, that you would have access to a machine capable of running the software, that you would have the skills required to use the software. Then again they might make it available for free or as an at cost cloud service, the thing is you don't know, so you can't rely on it.

Here are some file formats that the Library of Congress recomend:

Note: DNG preferred to RAW.

American Society Media Photographers archival best practise:

Here's what the ASMP say about archive formats:

"Currently, Adobe DNG format is the only candidate. Keep in mind, even DNG files may need to be migrated to a subsequent DNG version or a replacement format as yet unknown."

Why is DNG a better choice?

Because it is to all practical intents and purposes free from an intelectual property constraints, so any one who is inclined can implement DNG software and a quite a few organisations and individuals have. Not only have they written the software, some of them have made the source available  which means that other programmers can read it and if necessary modify t or port it (convert/translate it) to other operating systems or CPU families.
That means you are not reliant on a company that might go bust for future support of your files.

And for those people who want to be able to access the orignal RAW file - you can.
DNG allows the original RAW file to be embedded and extracted again later - though it may be a larger DNG than it other wise might have been.

Now I am not saying you have to use DNG or even that you should.
But I am saying I don't think most people have really thought the issue out and I think they should consider the issue carefully and not simply assume that they will be able to read their data into the indefinate future.

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