Recent comments

Reply to: Using Magenta Filter for Shooting With a dSLR Camera Under the Daylight   15 years 4 months ago

Magenta is 'Minus Green filter', but Red is 'Minus Green and Minus Blue'.

In daylight situation CC30M-CC40M produces near perfect sensitivity balance on my cameras.

Reply to: Using Magenta Filter for Shooting With a dSLR Camera Under the Daylight   15 years 4 months ago

A magenta filter will crosstalk more than a red filter, and CC40R or 30R would be easily obtained. Have you tried to make up a filter pack which will equalize the highlight clip position for all three channels in daylight?

Second question - to what extent do you think the IR-cut filters used are attenuating the far end of the red response, and might this be in part responsible for the low red sensitivity?

Reply to: About LibRaw   15 years 5 months ago

Yes, It works now with LX3 files. For first time I am seeing my true raw as it should be seen.
I will update you once I have a decent UI that uses libraw and it's up on sourceforge.

Thanks,

Reply to: About LibRaw   15 years 5 months ago

We've found and fixed bug in Panasonic .RW2 files processing. This bug affects only thread-safe version of library.

Could you please test LibRaw 0.6.2 on your files?

Reply to: About LibRaw   15 years 5 months ago

I've tried LX3 samples from photographyblog and process them without any problems on LibRaw 0.6.1.
Anyway, there is some strange problems when processing Panasonic files (in my tests - files from FZ28) on multi-threaded LibRaw version, so I'll check it.

You also may check new LibRaw release (sorry, source code only): http://www.libraw.org/blog/libraw-062-beta1.html

Reply to: About LibRaw   15 years 5 months ago

To test with any samples, you can use the raw files from here.
http://www.photographyblog.com/reviews_panasonic_lumix_dmc_lx3_3.php

If you scroll down there are bunch of RW2 files.

Thanks,

Reply to: About LibRaw   15 years 5 months ago

Hi There,
Thanks for the pointers. I am able to compile the code in VC++ 2008. Samples are also running fine.
I noticed in the list of cameras it says panasonic lx3 but the tiff conversion results in a file with only vertical line.
The same program works fine for Pentax K10D.

Is it because of dcraw only recently supported the LX3.
If so, will it be possible to reimport DCRaw latest version. It will be a while before new cameras will come out and this step may not be needed very soon again.

Thanks,

Reply to: OS X version -- Issues   15 years 6 months ago

Unfortunately, I've no Mac with Mac OS X Tiger. Will try to find VMWare image to test.

Reply to: White Balance in Digital Cameras: Problems   15 years 6 months ago

When is the article describing how to set UniWB into the camera going to be published? This is of great interest to me.

Reply to: About LibRaw   15 years 6 months ago

You can use digiKam DNG convertor as a reference. It uses both libraw and dng sdk.

Also, I'm not great VS2005/2008 guru. So, it is possible to provide Solution file, but I cannot be sure that it working. Makefile is much easier to test.

All CMake/Visual Studio/configure/automake and so on tools are scheduled to LibRaw 1.0. Too much things to do before

Reply to: About LibRaw   15 years 6 months ago

Thanks. I think not having good color is a secondary issue. The first problem is to inteface LibRaw with DNGSdk. If possible, could you provide some simple sample or write-up on how to interface LibRaw with DNG SDK.

Also, by any chance is it possible to provide a Visual Studio Solution for building LibRaw.

I looked around and even though DigiKam is very promising, but running KDE is not possible for everybody. Unfortunately, a lot of ppl are hooked on Windows.

Thanks for any help you can provide.

Reply to: About LibRaw   15 years 6 months ago

See below a thread about a stand alone version of digiKam DNG Converter tool running under Windows.

http://www.digikam.org/drupal/node/378#comment-17895

Gilles Caulier

Reply to: Zones and Digital: Two Methods of Exposing   15 years 6 months ago

> people have misunderstood ETTR in the past

Are you saying we are past that misunderstanding? My daily e-mails show direct opposite.

> he issue is that neither cameras not raw processing tools give a convenient method to see the (non white balanced) usage of the three raw sensor channels

The issue is not white balance only, but arbitrary statement of camera sensitivity as well. And channels are four, not three. Acting in presumption that G1=G2 is wrong.

> A solution needs to start outside the camera (and may be adopted, in time, in camera).

Real solution needs to start with the camera as we have less and less unprocessed data in what is commonly referred to as "raw output". Out of camera solutions are on many occasions just crunches as they can't take into account the modifications of data done in camera before the raw is recorded to a memory card.

Reply to: Zones and Digital: Two Methods of Exposing   15 years 6 months ago

So concretely, and irrespective of whether people have misunderstood ETTR in the past - the issue is that neither cameras not raw processing tools give a convenient method to see the (non white balanced) usage of the three raw sensor channels.

What can be done about this? A solution needs to start outside the camera (and may be adopted, in time, in camera).

Reply to: Zones and Digital: Two Methods of Exposing   15 years 6 months ago

> So how about posting a link to the images used for this article.

Those are thousands I discussed myself, and the point photographers were making was always "we are following ETTR", or, more specifically, often pointing to that article on Reichmann's site (and yes, his name is spelled with two "n" at the end). The images come from the everyday practice of pre-press, from different photosites, forums, etc. At some point in one pre-press bureau we were to arrange a practical shooting session to dispel the myth created by the phrase you quoted, "...bias your exposures so that the histogram is snugged up to the right, but not to the point that the highlights are blown." The idea that this note was written based on one image taken by one person is totally wrong.

The other problem with the ETTR as per LL approach is that it does not take into account how the camera actually meters, and how much negative compensation is already applied before displaying the histogram. For different cameras it is between 0.5 and 1 eV negative.

Reply to: Random And Groundless Thoughts On Color Control In a Raw Convertor   15 years 6 months ago

Dear Glenn, I'm afraid Lab was not designed to be perceptually uniform, but to be deltaE uniform.

Reply to: Random And Groundless Thoughts On Color Control In a Raw Convertor   15 years 6 months ago

Glenn,

Lab is definitely not the best choice. On the other side, we need some widely recognized color space for image storage/exchange. From this point, Lab is better choice (RGB and CMYK are imperfect, other color spaces are uncommon). L axis of Lab is good enough.

AFAIK, there is no 'digitizable' perceptually uniform color spaces. Munsell scale is good, but there is no easy way to calculate (perceptually) intermediate color values.

Reply to: Zones and Digital: Two Methods of Exposing   15 years 6 months ago

Actually, I'm not asking to look at many underexposed images, only the image used in the writing of this article.

I see underexposed, overexposed and correctly exposed images all the time and rarely do people point me to Reichman's artcle. In my experience, on balance most people who discuss the concept of ETTR have never read Reichman's article and are restating second and third hand information.

So how aobut posting a link to the images used for this article. If the information and position stands up, then it can only help.

Regards,

Peter

Reply to: Random And Groundless Thoughts On Color Control In a Raw Convertor   15 years 6 months ago

Interesting reading.

One thing that I would point out is that human vision is a tricky beast and it may be difficult to draw the right conclusions out of empirical results. There are many, many things going on at once... we can get a sense of that from the wide variety of visual illusions out there.

I've found myself that a lot of the theories out there are wrong... e.g.
http://colorcorrection.info/color-science/hermann-grid-illusion-nobody-k...

As far as building a RAW converter goes, some of the color models like LAB might not necessarily be what photographers want.
http://colorcorrection.info/color-science/is-lab-useful-for-color-correc...

---
In the grand scheme of things, I think that the psychology of the end user also plays a huge role. e.g. in premium audio cable, there are 'snake oil' products out there where people buy them because their expectations about the price (expensive=good, etc.) trump their actual perception!!
When looking at a photograph, there are noticeable differences between the reproduced image and real life. e.g. not 3-D, dynamic range cannot reproduce specular highlights, artifacts, etc. etc. We can tell whether we just looked at a photograph or through a window. But for the most part, people forgive that and don't pay attention to the technical flaws/shortcomings.

I think if photographers want to make truly ""realistic"" photos, there is art involved in the photographer tweaking the controls manually to look right. Part of this is to capture the 'signal processing' done by our brain. And sometimes part of it is to aim for naturalism... where the image looks like what it should look like.
To clarify what I mean by naturalism... in audio, we expect gunshots to sound like what they sound like in the movies (they have a certain roar from the compression effects applied to them). Yet actual recordings of gunshots sound very different.

Reply to: Settings for D3 to use with UniWB   15 years 7 months ago

The options are: use Auto White balance in NX (White Balance: Set Colour Temperature: New WB: Calculate automatically) as a first step and adjust from there; use click/drag grey white balancing method (White Balance: Set Grey Point); select the type of light in the scene and adjust colour temperature (for example - White Balance: Set Colour Temperature: New WB: Daylight: Cloudy); take a separate shot with custom white balance and copy in NX white balance from it to the shots taken with UniWB.

Reply to: Settings for D3 to use with UniWB   15 years 7 months ago

Hi, Having set my D3 up with UniWB. How do I then correctly process in NX2 the images capatured with UniWB so I get an image with visually appropriate White balance? Txs Mike

Reply to: Usage Examples   15 years 7 months ago

half_mt is just a simple(!) sample.

Anyway, to be fixed in next release

Reply to: Usage Examples   15 years 7 months ago

If one of the threads in half_mt encounters an error processing a file it quits but never restarts. Remaining threads, however, continue to function.

Reply to: Settings for D3 to use with UniWB   15 years 7 months ago

> Is there much image degradation if I were to use a gel (rather than glass filter) over my lens? I happened to settled upon a Roscoe Pink (4830) for my D80. After evaluating a sample set of Roscoe swatches alongside UniWB. I found that the Pink resulted in the least amount of Red and Blue WB adjustment for the D80 with flash as the light source.

When using flash as the only light source I always place the filter in front of the flash, not in front of the lens. This way no image degradation occurs.

If I need to use colour gel filters outdoors then I prefer Lee filters. When used with a deep compendium they cause image degradation on par with a regular protection filter.

Reply to: About LibRaw   15 years 7 months ago

LibRaw is based on dcraw sources. In turn, dcraw uses RGB-XYZ tables from Adobe (DNG converter? Or camera raw?). So, do not expect to get good color on digikam/LibRaw until dcraw and-or Adobe converter arrives

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