Started by Neil Hunt, November 04, 2007, 06:18:09 pm
Quote from: Lonnie Utah on August 12, 2011, 10:46:57 amhow did you make your graphs?? They are great!
Quote from: BobFisher on August 14, 2011, 11:46:23 amDon't disagree; but purely technical reasons are the only reasons to do things.
Quote from: Guillermo Luijk on August 12, 2011, 07:19:52 am* The flaw, or I'd rather say subjective point of this definition is what is a 'high dynamic range scene'?. My choice is to relate the decision to how difficult is to compress the scene's DR into the output devices' DR (paper: ~4 stops, monitor: ~6-7 stops) in a realistic manner that looks pleasant to the observer. Based on my experience, a escene with >8 stops of DR begins to require some processing but can still be tonemaped successfully without too much effort. >10-12 stops definitively needs a more skilled processing, and I consider it a good figure to speak about HDR imaging ...
Quote from: Lonnie Utah on August 11, 2011, 05:25:07 pmIt's also important to note, that while HDR images expand the dynamic range of the scene, don't really "expand" the dynamic range of the final image that we see. Most HRD software up-rezs the composite images to a 32 bit composite. If my calculations are correct that's 4,294,967,296 colors. This is a true expansion of the original Dynamic range. However, since our monitors and printers are generally 24 bit sRGB displays or 16 million colors, they can't display the 32 bit images, do the software DOWN-rezs them to 24 bit 16 million color images. This down rez effects both luminosity and color depth and compresses both. Both the uprez and downrez are "tone mapping".
Quote from: Monito on August 31, 2011, 08:00:52 pmIt's not 32 bits per pixel in the ordinary sense, which would be 10 or 10 2/3 bits per channel. It's 8 bits per channel with an 8 bit scaling factor. Thus it is like a floating point number, and has much greater range than 4 billion colours.
QuoteMost HRD software up-rezs the composite images to a 32 bit composite. If my calculations are correct that's 4,294,967,296 colors.
Quote from: BobFisher on September 09, 2011, 07:52:32 amHDR is 32 bits per channel not 32 bits per pixel (i.e., 10 and change bits per channel). And yes, it is uprezzed from the 8, 12, 14 or 16 bit original input images.Andrew is right about why the need for floating point. There are just far too many possible colours to be created to keep them all in an integer space. It's got nothing to do with the dynamic range.
Quote from: BobFisher on September 09, 2011, 08:43:01 amWell, I'm not a mathematician but I don't see how an integer based system can have as many colours as a floating point system. If even going to one decimal point, I can get 9 more levels between each integer in each channel. To me, that's more colours.
Quote from: BobFisher on September 09, 2011, 07:52:32 amEnfuse is a nice program, particularly with Tim Armes' LR front end. It's not true HDR; however. The images don't enter the 32 bit space but are retained in the native bit depth.
QuoteEnfuse is an image blending program rather than an HDR program. Because you're not going through the strong local tonemapping routines of an HDR tonemapper that's why it tends to give more natural results. It's the local contrast operators that really take you into the land of the surreal. Natural results can be obtained with actual HDR programs as well; some more effectively than others, it just takes a little more work and practice.
QuoteWRT multi-processing a single file and feeding those into Enfuse, you're not gaining anything Andrew. You're not gaining additional DRange by multi-processing the single RAW file
QuoteWhile I like the results that can be achieved with Enfuse, my biggest issue with it is speed. I find it brutally slow so it's not viable for a volume workflow. But it does produce really nice results.
Quote from: Guillermo Luijk on September 09, 2011, 10:00:15 am... So HDR is not about floating point formats...if you have a camera that can capture in a single shot 15 stops of DR, create copies of this capture at different exposures, and blend them some way to obtain an output image that can display the entire DR of the original scene into some monitor or print, then you are doing HDR.
Quote from: BobFisher on September 09, 2011, 09:32:36 amIn an integer system, I can combine R=8, G=57, B=240. That gives me a combined colour. It's sort of a neon blue. But if I can combine R=8.1, G=57, B=240, that's a different combined colour. It's very close to the previous one, but it is different.
Quote from: BobFisher on September 11, 2011, 10:31:53 amIn the photographic sense bracketing is required because no capture device can represent such a broad brightness scale.
Quote from: BobFisher on September 11, 2011, 10:31:53 amIt's what happens in between that's the issue and where I think I'm not completely following your line of thinking.
Page created in 0.030 seconds with 14 queries.