LightZone 2 released

[Asher Kelman]

We're looking forward to as many LightZone versions as we can get here.

I really like the concept behind this software.

Asher

 

[Uwe Steinmueller]

>Interesting, while I haven't seen a hint of dcraw with v1, I have it in LZ's folder after upgrading.

DCRAW is used to read the file formats not for the RAW conversion.

Uwe

 

[Asher Kelman]

Hi Uwe,

Welcome back! Good to have you here. Great for you to share your experience.

Asher

 

[Uwe Steinmueller]

Only very few people may even know that the forum name was my idea


Asher, you have a very nice group of people here. I will chime in now more often.

Uwe

 

[Asher Kelman]

Uwe,

You are a delight!

Yes, the guys here are really great. Everyone is interested in getting to the best prints!

Asher

 

[Uwe Steinmueller]

>Everyone is interested in getting to the best prints!

That is all I care about.

Uwe

 

[Asher Kelman]

Hi Fabio,

As you may know, I and others have become quite interested in the new M8 Digital Rangefinder from Leica. So I was perplexed and frankly a little disheartend to hear that the M8 might in your view be Gamut challenged. It could be that I'm reading your words wrong.

I don't mean to dimish your hopes, but it doesn't look promising to me. For the little I know of color theory there is no profile that can fix the problem. The profiles available for C1 are actually pretty horrible, if you verify the equivalent color gamut obtained with them you can see that it is smaller than sRGB. I think Leica needs to fix the camera...

- Fabio

Anyway, I asked about this in the Leica Users Forum where Jamie Roberts, (the photographer who has labored and made avaliable the C1 profiles) posts.

Hi Jamie,

I'd like to know if you have any idea as to the gamut of the files processed with the new profiles and the blocking filter.

Do you have any feel for it. I had an email from the designer of a respected RAW software program asserting that the gamut was much smaller even than sRGB after processing!

Is there any impression as to whether or not this might be even partly true?

Ciao,

Asher Kelman

Hi Asher,

That's very odd--my feel for this is that sRGB isn't nearly capable of handling the calculated color gamut, though I'd truly bow to other's expertise here.

I'd love to know the gist of what he or she means by this. What is the repected RAW developer saying? That the C1 profiles are doing this? Or that the IR filters are doing this?

There are no profiles, to my knowledge, that take advantage of the IR filters yet.

So far, the profiles I've tweaked are meant to work around NOT having filters, which, since I can't find them anywhere to buy, I don't have anyway right now.

So I don't have any sense whatever about the resulting colour gamut of tweaked profiles + IR cut filters. We need new profiles to go with the IR filters, is my feeling.

Having said all that, I don't think shots I've been taking fall within sRGB for the most part. Again, blues are a dead giveaway in my experience...

Just to test this, I developed a couple of shots from my last engagement shoot with C1 and the chrome profile I've been playing with. Output to J.Holmes DCam4. Then I soft-proofed the results to sRGB in Photoshop, and almost half the file--all saturated reds and blues--were outside of sRGB gamut.

So I don't know what they're thinking...

Even more certainly, the profile isn't clipping the camera response! Gretag Macbeth Profile Maker 5 reports that the resulting tweaked profile I've been using is actually actually bigger than Adobe RGB--let alone sRGB--particularly in saturated blues.

Here is the 2d plot from ProfileMaker. As I think Michael Reichmann said in his review, this probably doesn't really mean that much, but here it is FWIW. What the 2d plot doesn't show is that at certain points the aRGB profile is actually larger--it's not completely contained.

Blue outline is the chrome profile I tweaked; inside red outline is Adobe RGB. As you can see, there's quite a bit in the profile, anyway, that's outside aRGB. I'm not sure why the camera would not respond within the profile... or why it would be otherwise limited, but I sincerely doubt that the resulting colour is limited to less than sRGB.

At least, it cannot be the profile doing the limiting, in my understanding.

So, did I misunderstand what you wrote. Certainly there's a gap here!

Thanks Fabio,

Asher

 

[Uwe Steinmueller]

I think Jamie's gamut plots are correct.

On the other end I care very little about gamut plots and look at pictures instead .



Uwe

 

[Asher Kelman]

Thanks for your rapid comment, Uwe!

I do believe in Gamuts. They exist! It's not like an Elvis sighting!

Of course, you are correct, the final print matters to us, but I'd like to know what leads Fabio to his conclusion that the M8 gamut is smaller than sRGB? It's likely that some context exists for the statement as Fabio praised the camera.

A lot hangs on the words and writing of all of us. I myself am looking to purchase 3 M8 bodies and lenses. Now I cannnot ignore what has been said.

Meanwhile, I'm pragmatic. I take pictures with the M8 and so far, like them very much!

Asher

 

[Uwe Steinmueller]

>I do believe in Gamuts. They exist! It's not like an Elvis sighting!

Of course. But first a good content and a nice print. But also our own images show not so high saturation which makes it easier to live with a lower gamut.

Uwe

 

[Asher Kelman]

>I do believe in Gamuts. They exist! It's not like an Elvis sighting!

Of course. But first a good content and a nice print. But also our own images show not so high saturation which makes it easier to live with a lower gamut.

Uwe

Easier to live with a lower gamut?

Uwe,

From where? From LZ? Or, perhaps this is a general comment.

Also why does/would decreased saturation make it easier to live with a lower gamut? I don't understand!

However, I know you are talking from your experience with your prints.

Asher

 

[Uwe Steinmueller]

>However, I know you are talking from your experience with your prints.

I think higher saturation makes life more complicated.

Also I am easy going: Once I like a picture I don't ask about the gamut . Actually other people like the prints too. Too bad that the web cannot show how real print look like.

Uwe

 

[Asher Kelman]

I had the great pleasure on joining Uwe and Bettina, his wife, both talented photgraphers at the first Photographer's summit which he organized.

Uwe shared his prints and everyone enjoyed them!

Asher

Still, the gamut question with LZ is not answered but you are not to blame!!!

 

[Uwe Steinmueller]

Here is my take on Jamie's profiles: As we all know they are not the solution but can rescue many images.

I think Jamie did the Leica community a great service.

Uwe

 

[Asher Kelman]

Fabio,

Could you comment on the sRGB comment for the M8 files?

Thanks,

Asher

 

[Fabio Riccardi]

The M8 JHR gamut issue

Hi Asher,

my understanding of color theory is small, but it appears to me that the primaries used by the M8 JHR color space define a quite narrow gamut of colors, see screenshots below, compared to sRGB.

Best regards,

- Fabio

 

[Fabio Riccardi]

Hi Again,

out of fairness, this is a superimposition of the 3D rendering of the color volume of Adobe RGB and the M8 JHR color space I have seen. The solid volume is Adobe RGB, the wireframe is M8 JHR. The two color spaces are comparable in volume, but aRGB can represent more colors on the blue/green side while the JHR profile can represent more colors on the blue side...

- Fabio

 

[James Roberts]

Hi Fabio,

First--thanks a million for LightZone. It's the most promising RAW converter I've seen to date (though I'd kill to have a way to quickly set BP and WP like a curves / levels control--as well as the zone control for fine tuning). I think the M8 is going to be a perfect match for it, once the colour response of the camera is figured out

But I think the whole problem here is that you've been looking at the V1 profile while in conversations with Asher in other places I've been using something called the "chrome" profile.

And thanks very much for your clarification; your analysis of blue vs blue-green response in the original V1 profile, compared with aRGB--along with limited red curve--is exactly what I'd expect from that initial profile, and exactly what I see from PM5 graphs too.

But this reflects more on my ability to create C1 profiles than on the camera or sensor response, I think

As some background, that JHR V1 M8 profile was just a ridiculously fast attempt to 1) correct the (IMO) awful original C1 M8 profile in terms of LAB values for the test patches I could measure, and under tungsten light to boot 2) Map out the magenta cast to black synthetic as an immediate workaround.

It is most definitely understaturated, but not too bad compared with sRGB (larger everywhere except on the yellow side of things).

Of course, a narrow output profile is bad for input processing, but, at least given subject matter, has some advantage for printing, since you're not torquing primaries to fit a CMYK space (small in and of itself). Perhaps this is why I've heard from a lot of people that they like it

But when Asher asked me to respond to your comments, I was by then using an interim--but much more fully saturated--profile I've been calling the "chrome" profile.

It's goals were to see how much I could push the profile (without artifacts) in terms of both saturation and shadow contrast (like a chrome film)--and increase exactly the deficit blue-green response--without, again, getting making the magenta problem any worse.

So it's now way over-saturated But once I get some better profiling equipment here, I will be able to fine-tune it. So far, it looks to be much greater in volume than aRGB (not usefully so, probably), except where the luminance levels need to be controlled in the magenta space.

So I think it's a good "step along the way" for the M8. If you have any comments, I'd love to hear them!

Here is what PM5 reports (which I posted on the Leica Camera user forum) both profiles, using aRGB as the control (sorry I don't have the wireframe! What colour analysis tool are you using? Something like ColorThink?):

First, the same as Fabbio's--the M8 V1 JHR profile vs aRGB:

Next, the 3d plot of the newer Chrome profile against aRGB. With the exception of a little magenta blip (no kidding), a small deficit in the blue-green (again) and a difference in luminance response (due to the compression curve that's in this profile, I think), the Chrome profile is significantly larger than aRGB, though primaries may be still a little narrower (which, again, might make processing harder but should make printing easier):

Just for another view, here's a 2d AB plot of the response. The Chrome profile is *over-saturated*--producing, in Margullis's lingo, anyway, "imaginary LAB colors" (which is ok in this interim step).

Finally, all three together in a 2d plot. You can definitely see the difference

 

[Fabio Riccardi]

Hi Jamie,

thanks for the update, this looks more promising. Personally I'd live with the MG cast or use a real IR filter, after all people used to ruin teir good lenses with UV filters for ages, right?

For the quick "levels" control for WP/BP in LZ here is the recipe:

1) bring up a ZoneMapper
2) on the ZoneFinder find the brightest thing in your image
3) grab the corresponding segment and bring it up all the way until it looks right to you
4) similarly find the darkest thing
5) grab the segment just below that and bring it down until your shadows appear dense enough
6) you're done.

As a quick PS-centric explanation to the esoteric procedure illustrated in the six steps above, think of the ZoneFInder as a histogram with 16 bins, one for each zone, and active for every pixel in your image. Then it is trivial to derive that identifying the brightest and the darkest parts of the light distribution allows you to know where to stretch.

Cheers,

- Fabio

 

[Asher Kelman]

Thanks Fabio for the insight.

Good to have you here! I know for sure, Jamie is a fan of yours already!

Asher

 

[James Roberts]

Fabio--

On the filters for the M8--well, I can't find any! So profilng is the only workaround I've got

But honestly, the practical results with new profiles has been so promising that I'm not really concerned about the filters that much. They're going to be nice to have when I get them, but I'll still re-profile the camera (if C1 doesn't beat me to it, which I would be happy to have happen).

I'm also beginning to suspect that perhaps the faulty hardware part in the early production M8s is contributing to some colour funniness--the shots from the newer cameras trickling out seem much better to my eyes, but it's early yet.

Ah well! Thanks so much for the LightZone WP/BP tip, and thanks again for the program!

 

[Fabio Riccardi]

Hi Jamie,

how difficult would it be for you to make a linear profile (i.e. not gamma encoded) for the M8? I could use it for LightZone...

- Fabio

 

[Ray West]

Light Zone 2.0.4 is out now

title says it all, installs ok.