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Stable release: 0.6.x
What Is LibRaw
LibRaw is a library for reading RAW files obtained from digital photo cameras (CRW/CR2, NEF, RAF, DNG, and others). Details >>
LibRaw is based on the source codes of the dcraw utility, where part of drawbacks have already been eliminated and part will be fixed in future. The users of the library are provided with API to be built into their software programs.
Administrivia
Submitted by lexa on 12 October, 2008 - 11:22This site has moved to another database engine (to PostgreSQL from MySQL). We does not expect any changes from user's point of view.
Anyway, if you have any problems with libraw.org site, please contact site team via comments to this note, or via contact form or by E-mail at info 'at' libraw 'dot' org.
Random And Groundless Thoughts On Color Control In a Raw Convertor
Submitted by lexa on 1 October, 2008 - 22:30
CAM book
After finally finishing reading Fairchild’s Color Appearance Models I started to get deep into thought and some empirical things became clear.
Color Contrast
In the photographical community it is pretty much a common place that if you show the viewer two pictures, one with normal colors and one with an increased saturation, the viewer will in most of the cases pick the one with the higher saturation (if it is, for example a landscape scene) as the more natural one (of course if saturation is increased in the reasonable limits).
I could not quickly find the wording of this effect in books by Margulis, although I was almost certain that it was there in one way or another: in his book Photoshop Lab Color) this rule (increasing the a-b axis contrast) is used starting with the very first example.
Canon: How To Get 400/5.6 In Five Different Ways
Submitted by lexa on 29 September, 2008 - 21:35
Competitors
While preparing for my summer trip to Altai, I attended to choosing the telephoto lenses I was going to carry. I needed a regular telephoto lens for shooting water attractions (Katun is very large river and the target can be very far away) and an extra long reach lens for shooting the full phase of the solar eclipse.
The goal was to select a 400 mm as a “long” lens, and as much as possible for the “extra long” one. After looking around and asking some friends I found the following possibilities for a 400mm with Canon:
- EF 400/5.6
- EF 300/4 + TC1.4
- EF 200/2.8 + TC2
- EF 70-200/4 + TC2
- EF 135/2 + TC2 + TC1.4
Surprisingly, even the last option on the list (the one with two teleconverters stacked) did not seem hopeless: I tried that option for film a while ago, and it was comparable with a 70-200/2.8 with a 2x TC.
LibRaw 0.6.1 Release
Submitted by lexa on 25 September, 2008 - 22:25Changes since 0.6.0:
- Added new data field float LibRaw::imgdata.color.cam_xyz[4][3]. This field contains constant table (different for each camera) for Camera RGB->XYZ conversion.
- All client code should be recompiled
Your can always download latest LibRaw version from this site's download page.
Peace in Lights
Submitted by ib on 23 May, 2008 - 17:49
Compensating ETTRAs it was shown earlier the direct application of exposure to the right method (ETTR) without preliminary scene analysis and evaluation often results in a major underexposure which in turn causes poor details, noise, and artefacts. In order to evaluate the necessary depth of tone correction for such underexposed shots we will use the following natural method – we will return the zones containing details of high visibility (those are zones from IV to VI) to target density values. Such a move makes sense because in order for those details to be really visible, they need to be in those zones.
About LibRaw
Photographers using digital cameras know that shooting using the RAW format, where "raw" data from the camera matrix are saved to file, provides the highest flexibility for further processing. At the same time, photographers and pre-press specialists still can't enjoy the full potential of the RAW format, since most popular converters significantly and irreparably impair the quality of the initial material.
Developers willing to get rid of this sad discrepancy run into a vast diversity of formats and either have to waste time and effort on studying them, or confine themselves to a limited set of formats, or use ready solutions for extracting RAW data for furher manipulations and rendering into an image.
Most software products for RAW file processing extract the input data using code that is based on the source of the dcraw utility by Dave Coffin. For all its evident advantages, however, dcraw is a command-line utility rather than a software library. As a result, one should either make his or her library from it (and many developers, including Adobe, have followed this way) or use the dcraw command line (which is far from convenient, too).
In addition, dcraw tampers the data at the extraction stage and does not extract some of important parameters from the RAW file, thus impairing the quality of the result.
On the basis of the above reasoning, the authors have decided to create the LibRaw library, which is presented on this site.
- Right now LibRaw can be built into your software.
- Right now part of dcraw problems have been resolved.
- In the nearest future, further processing will be improved after some modifications in the library.
LibRaw is intended to be used in any software that involves RAW file processing for a variety of purposes: RAW converters, data analyzers, panorama stitchers, noise suppressors, etc.
LibRaw is free and distributed in source code under the terms of GNU GPL v2 (or later). Licensing under other terms is also possible for free; please contact the authors.
About This Site
Besides developers using LibRaw (and possibly our future software), we'll be glad to see the other readers and contributors to this Web site:- authors willing to publish their papers on image processing, color management, specific features of digital photographing, and other similar issues
- photography enthusiasts willing to understand how all these things work
- computer programmers (programmers interested in photography, photographers interested in programming...) willing to announce their products.
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