What is the difference of a DNG file Vs a JPEG file ?

[just me]

I have started just recently to shoot in RAW format, and have noticed that after I have edited a RAW file, I can choose to have these converted either in TIFF or DNG or JPEG, so please can somebody explain to me what is the difference of TIFF or DNG file against a JPEG file ?

I know that a TIFF or DNG file are larger than a JPEG file, but has it any effect on the qualitaet of a photo ?

Griddi......

[Inkanyezi]

Tiff and jpeg are image formats, while your raw file is raw unprocessed data.

Tiff can be saved in various ways, so it's not a single thing actually, and your software may have different options. Tiff files are large, hence contain much data, and they are saved without any loss, although they are processed for colour, curves etc. If compression is used, it is lossless, so all data that is present after raw conversion can be restored.

Jpeg is a compressed image file using algorithms that discard data, a lossy format, so it can be saved as a very small file. There are various options for compression of the jpeg, which display different amount of loss, The original data cannot be restored from a jpeg file.

DNG retains all original raw data and is not processed. It is intended as a general replacement for the raw file, that can be processed in various programs and would not need a dedicated raw converter. DNG is a similar size as the raw file, but unlike RAW, it is a standardised format, hence more universal. There are no two chips that use the same raw format.

[just me]

Thank you very much Urban for the information......

As I want just to keep the original RAW file, it does not make any big difference if I keep the file as RAW or DNG, is this correct?

Griddi.......

[Inkanyezi]

As long as you have a RAW converter that supports your RAW format, you are safe with the RAW file. The advantage with DNG should be that there are more programs that support it, and that you can use the same program for all future cameras you may acquire. If later on you might drop your old RAW converter for some reason, you old RAW files might not be supported by newer programs - less likely, but it has happened at least once. DNG is supposed to have future support.

[just me]

As long as you have a RAW converter that supports your RAW format, you are safe with the RAW file. The advantage with DNG should be that there are more programs that support it, and that you can use the same program for all future cameras you may acquire. If later on you might drop your old RAW converter for some reason, you old RAW files might not be supported by newer programs - less likely, but it has happened at least once. DNG is supposed to have future support.

Hmmmm, now it looks that I would be better off with DNG files, as I have found out already, that LR 3, does not support my RAW files taken with my Olympus E-M5 camera, and the same applies to photos taken with the E-M5 if I like to use Silkypic, then I have found out in the meantime I have to convert these files to DNG to be accepted with LR and Silkypic......

Griddi.......

[Colin Southern]

Keep in mind that a DNG IS a RAW file - it's simply a RAW file in a standardised format.

I've used them exclusively for years -- and continue to recommend them. I don't even keep my original RAW files out of the camera anymore.

[Manfred M]

Hmmmm, now it looks that I would be better off with DNG files, as I have found out already, that LR 3, does not support my RAW files taken with my Olympus E-M5 camera, and the same applies to photos taken with the E-M5 if I like to use Silkypic, then I have found out in the meantime I have to convert these files to DNG to be accepted with LR and Silkypic......

Griddi.......

A word of caution; not all software can read DNG files, for example DxO Optics is fine with RAW formats from various camera manufacturers, but does not support DNG files for input. I found this out the hard way; I converted all of my files from a trip into DNG and later on found the software cannot read them. I now have to do a fairly convoluted work around with that set.

I now keep all my images as RAW (in my case Nikon NEF) and only convert when I need to. That gives me maximum flexibility down the road.

[just me]

Thank you Colin, after reading Manfred's post, it seems everything has two sides, so I think I will keep for the time being the RAW files, and when needed convert to DNG .........

Merry Christmas to you and yours,

Griddi.....

[just me]

Thanks Manfred, I will keep better the RAW files in the RAW formats, and as you said, convert them when needed into DNG, it is truly true, as more one reads / hear the harder it is sometimes to come to a decision.......

Wishing you a Happy Christmas,

Griddi.....

[Glenn NK]

As I want just to keep the original RAW file, it does not make any big difference if I keep the file as RAW or DNG, is this correct?

Griddi.......

This is a touchy subject which can open up some rather heated discussion.

There are many opinions; some people immediately convert their RAWs to another format (TIFF, PSD, DNG), while others believe one should keep the RAW files, and still others convert and keep both on their HDDs.

Very often it comes down to the software one is using; using Lightroom (which does not modify the RAW file), I only convert on two occasions:

1) when another program (for example Zerene, a focus stacking program) requires something other than RAW. This particular program recommends converting to 16 bit TIFF files which are HUGE. As soon as I'm finished, I delete the TIFF files.

2) when I export a file for printing - a printer can make no sense of a RAW file at all - it must have an image file. These are also deleted after printing, but others may have very good reasons for keeping them.

As I suggested, there are many opinions on the matter, and you've heard some already. As a user of one of the major brands of camera, I'm not particularly worried that my brand of RAW file will become obsolete - the software writers (Adobe comes to mind), simply can't take a chance on not supporting the RAW files of major camera makers.

Adobe's DNG format may not be quite as "standard" as we may be led to believe; there has been a recent additional (compromise) file size choice added to DNG.

http://www.dpreview.com/news/2012/10...ssy-DNG-option

Converting a RAW file to some other format is somewhat akin to mixing and baking the ingredients for a cake - once done, it cannot be unmixed and unbaked. So, unless one is using some obscure camera brand that won't exist next year or tomorrow, there may be no advantage converting all the files to a format other the format the camera produces (RAW).

Glenn

[Geoff F]

Thank you very much Urban for the information......

As I want just to keep the original RAW file, it does not make any big difference if I keep the file as RAW or DNG, is this correct?

Griddi.......

It does make a difference in file size and if you produce a lot of images that difference can soon mount up. At least when I compare my files between CR2 and DNG.

So I have started saving in Dng to gain a little extra space. However, there are a few other drawbacks to consider.

Dng does take a little extra time for me to download. Around 10 minutes extra for 100 images with my computer. So if you are regularly shooting 300 or more photos a day this can be something to consider.

Those 100 shots will take me about 30 mins to download as Dng. And my computer is reasonably powerful. But I'm using a 7D so the files are fairly large to start with.

The second problem which I encountered was corruption of a few files during the download, but this stopped when I doubled the amount of RAM in my computer.

Try a few sample files noting file size and download time then decide which suits you best.

[Manfred M]

Thanks Manfred, I will keep better the RAW files in the RAW formats, and as you said, convert them when needed into DNG, it is truly true, as more one reads / hear the harder it is sometimes to come to a decision.......

Wishing you a Happy Christmas,

Griddi.....

Griddi - essentially you have to figure out what works best for you. There are no magic solutions that work for everyone all the time and there are advantages and disadvantages no matter what solution you end up using. I tend to leave my options open and that generally means that I have higher storage needs that others, but storage is fairly inexpensive these days and I probably only shoot some 10,000 to 20,000 images a year so a bit more hard drive space doesn't make a lot of difference to me.

[Colin Southern]

A word of caution; not all software can read DNG files, for example DxO Optics is fine with RAW formats from various camera manufacturers, but does not support DNG files for input.

True, but then again, (a) DxO is probably by far the biggest exception, and (b) functional equivalents to DxO are already included in ACR.

Personally, I think DxO risks the same fate as the dinosaur if they continue to snub DNG ... Users have been asking for it as an input format for years.

[just me]

To all of you my THANK YOU for helping to answer my question.....

As I am new to shoot RAW, I will for the time being at least keep the files in RAW format, till I find out what suit me best......

Hope you all had a happy Christmas.....

Griddi.....

[Inkanyezi]

Now that hopefully it won't cause confusion, I'll put down a note on TIFF. A TIFF file can be a container, and there is enough space for all raw data within that container. So some digital backs use this to simplify life a bit for users, branding their RAW files .TIF so that for example Windows will regard it as an image file and handle it accordingly. Inside that .TIF there also is an image file that the image display program can read, so they do display a thumbnail, and they open in the image viewer. However proprietary RAW converters, as well as most third party converters, also read the RAW data and can process the RAW file contained within.

There is a caveat with this approach. RAW files are never overwritten by RAW converters, but they use parameters for processing when they display the image, and then the RAW is exported as an image format after it is processed with the parameters that are set. Evidently a file that ends in .JPG or .DNG or .TIF will never overwrite a file that has the extension .CR2 or .ORF or .NEF. But your image processing software may overwrite a .TIF file, only with a dialog box asking if you really want to overwrite the existing file.

[davidedric]

It's still Christmas here, just . I know you have signed off Griddi, but just in case the options aren't sufficiently confused..........

My workflow is to import all my RAW files from camera (in my case .CR2 files) to an external hd, select the ones that I think are potential keepers and copy them to a new folder in my LR directory. Then I import the new folder into LR, converting to .DNG on the way. That way I have all my original RAW files on an external hard disk, and the ones I think I want to work on stored on my internal (mirrored) disks.

Does that make sense to the experts here?

[HenkB]

One other observation on the usefulness of DNG. Once converted to DNG, raw files of newer cameras not supported by older raw converters can be opened and processed. Swiss army knives are almost never absolutely the right tool but, heavens, they are useful.
Best, Hendrik