Your processing of the image in the comments section here (the rainbow over the stream) is a very fine example of extracting the maximum amount of dynamic range from a photo that looks quite flat in its original state. Would it be possible for you to do a future tutorial on your post-processing of this photo from beginning to end? It may make a fine example for those of us just getting into RAW and 16-bit processing. Thank you!

Julien :
Yes, I would like, unfortunately I don’t have enough time right now

Your extra explanation, combined with the pictures, makes it very clear that there is difference between the DR of RAW and JPG.

But, do you know what it is that makes that difference? Is the in-camera processiong from RAW to JPG? Or is it the hand of the photographer who uses the slides in his RAW-conversing-program? I don’t know and maybe it’s interesting to figure it out..

Julien :
Yes, as said in the 2 articles here and here, the in-camera processing is downgrading the richness of the picture because :

1. The white balance and processing is done by the camera, this is a destructive process.

2. The richness from the source is truncated from a 12Bits (4096 shades per channel) to a 8Bits (256 shades per channel) definition, so this is also a destructive process

I don’t say that JPG is a bad format, I just say that I consider it as a final export format after post-processing, when all choices are done.
If I would like to make a parallel between the digital and analog world, I would say that using JPG is like having the final print without having the negative.
Of course if you don’t post-process you pictures, you probably don’t need the raw data .

I clearly see the advantage of RAW against JPG. Many thanks for that demonstration. But why underexpose in the first place? I mean, I see you did it on purpose to show the advantage of RAW, but in the real world, this photo has to be done again on the site (in the room at that moment), to the moment you get a good exposure. At least, that’s how I work. I need to have a good picture before I leave the set. With modern lcd-screens it’s easy to see if the image is good or bad.

In the old days, photographers just put a sheet of grey plastic on the window.. Pre-processing, instead of post-processing, think about that. I believe that will result in even better quality!

Julien : Thanks Joep, that’s an excellent question. What I wanted to demonstrate here is the richness of the RAW against the JPG, but I perhaps forgot to say why? Is it to recover a bad exposure? No, I use it because it is the way to capture the largest dynamic range of a scene.

Now, capturing the largest dynamic range is not always useful, but in certain circumstances, especially landscape photography, it is because you often have a big difference between the luminosity of the ground and the one of the sky. Look at this example :



You could say that the original is badly exposed (underexposed) but I wouldn’t agree with that. I did this intentionally to preserve all the details in the sky given the fact that I didn’t have any gradient filter to darken the sky or any tripod to shoot 2 different exposures that I would have mixed in the future. I did know, with the given light of the scene, that the dynamic range of the RAW would be enough to have a good result after the post-processing even if the original was not homogeneous. If I had exposed differently:
More: a part of the sky would have been overexposed, so details would have been lost.
Less: the ground would have been to much underexposed and the richness of the raw wouldn’t have been enough to recover clean details.

Finally, because the iso was low (100) the noise was low and I had no difficulties to neatly enhance the luminosity of the ground. Doing that with a JPG wouldn’t have given the same clean result.

Note that in the old days, photographers were already “burning and dodging” in their darkroom, the way was different because it was the argentic analog world but the concept is exactly the same (see Way Beyond Monochrome by Ralph W. Lambrecht & Chris Woodhouse or The Print by Ansel Adams).

Je crois avoir acheté le photoshop elements 5 qui dit traiter des Raw, certains au moins, où je peux trouver des images Raw pour essayer, jouer avec? tester les possibilités?

Julien : Oui le terme “Raw” ne veut rien dire d’autre que “données brutes”, donc ça peut aussi s’appliquer au domaine du son.
Voici un Raw de mon D200 sur lequel tu pourras t’amuser : Raw test

Julien : Thank you Tom, I think you will have all answers here

Julien : I said the Raw format was a better source for post-processing, talking about raw for printing is disturbing for me because Raw is the beginning and Print is the finality … there are many steps between them. However I think that to have a good print, you need a good post-processing, to have a good post-processing you need a good/rich source and to have a good and rich source you need the Raw.