"Exposing to the right" is over exposed, what now?
in [Photoshop]
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From: Floyd L. Davidson on 11 Oct 2009 17:36 Porte Rouge <porterougeman(a)gmail.com> wrote: >On Oct 10, 3:30�am, fl...(a)apaflo.com (Floyd L. Davidson) wrote: >> sigh... <s...(a)noaddress.com> wrote: >> >On Thu, 08 Oct 2009 18:36:37 -0800, fl...(a)apaflo.com (Floyd L. Davidson) >> >wrote: > >> Setting White Balance will have a dramatic effect of the >> accuracy of both. > >Could you tell me how you go about setting the white balance on your >camera? I read this page: > >http://www.guillermoluijk.com/tutorial/uniwb/index_en.htm > >The first method is over my head and I have a Nikon that doesn't use >saturated pixels for the calculation of white balance. My white >balance can be set to Auto(+ or - 3), by lighting(tungsten, >fluorescent, flash), outside light (direct sun, shade, cloudy), select >a temperature, and presets(measure a gray card or use WB from another >photo). Which would you recommend? I use Nikon cameras and shoot RAW+JPEG virtually all of the time, using the JPEG for preview only and process RAW files for production. The JPEG is often enough previewed using the camera's LCD (I show somebody a shot that was just made, or even let them scroll through several images), but is usually seen via a laptop LCD. Hence a realistic JPEG is important, but does not need to be perfect. Also, I use the histogram as a rough indicator of exposure, and the "highlight" display to actually decide if an image was exposed correctly. I always use "Auto" for White Balance. The significant effect of doing so, for my workflow, is that the camera records whatever multipliers were used. If a preset WB setting is used, the preset multipliers are recorded, but we already know what those values are so recording them is not useful (they are also used as preset values by the raw converter). By using "Auto" I get a record of what the camera thought WB should be. When I process the RAW file (I use UFRAW) I can use the camera generated auto values or I can use what the program's "auto" setting generates. Sometimes they are very similar, sometimes not, but usually one or the other is close enough to what I want to provide a starting point for manual adjustment of the program's White Balance. I have tried the UniWB concept, and it certainly works as described. It was nice to have a very accurate JPEG in terms of the histogram's indication of exposure, but... I can't live with the greenish looking JPEGs produced. :-) I can live with knowing that to nail exposure I need to allow at least some portion of the image to blink in the highlight display. I just keep in mind that getting more dynamic range means a little more area blinking, and positively avoiding clipped highlights means a little less. It's a judgement call that depends on circumstances, and in any case is never very critical. A lot of folks say what they want is an histogram generated directly from the camera's raw data. Un-interpolated raw data histograms aren't very useful though! What I would like to see is the camera do one interpolation for the JPEG image and an entirely separate interpolation for a histogram. For those who shoot JPEG, the settings would be the same (or just use the JPEG for the histogram as is now done). For those who shoot RAW the interpolation could be set for using 1.0 multipliers, low saturation, no sharpening, and a standard gamma, to get a very accurate histogram. I wouldn't mind seeing an "expanded" histogram display either, where the entire graph shows only the upper 2 fstops of the histogram and also truncates the vertical range by 1/2. What a tool that would be! -- Floyd L. Davidson <http://www.apaflo.com/floyd_davidson> Ukpeagvik (Barrow, Alaska) floyd(a)apaflo.com
From: Bob Larter on 12 Oct 2009 02:55 Paul Furman wrote: > OK, this makes sense, the posterizing issue is not really visible in any > sort of normal exposure. What about Floyd's comment below that the noise > level remains the same but exposing to the right increases the signal so > that overwhelms the noise? That seems to tie the two together in a > comprehensible way. Look at it this way: Your RAW image will have the same amount of noise, regardless of the exposure. But exposing to the right will lift the shadow levels up higher, relative to the noise. When you process the RAW image on your PC, you'll lower the brightness levels back down, thus lowering the absolute noise levels with them. More technically, you're maximising the signal-to-noise ratio. -- W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^---------------------------------------------------------------
From: Paul Furman on 12 Oct 2009 11:31 John A. wrote: > On 11 Oct 2009 09:59:27 GMT, Chris Malcolm <cam(a)holyrood.ed.ac.uk> > wrote: > >> In rec.photo.digital.slr-systems Paul Furman <paul-@-edgehill.net> wrote: >> >>> What about saturation? Reducing saturation seems to give more detail to >>> the edges also. >> That could be a side effect of chromatic aberration. Do you notice it >> when there's no chromatic aberration? > > Or from chroma subsampling if you're working with jpegs. I don't think either would have much effect. It looks to make as big of a difference as contrast. -- Paul Furman www.edgehill.net www.baynatives.com all google groups messages filtered due to spam
From: Porte Rouge on 13 Oct 2009 19:22 So, with WB all set you take a picture. I gather that you expose to the right? My sunrise is good example of lighting conditions that lead to especially washed out colors if you do. How do you adjust the colors in post or do you just meter for the sunrise and let the histogram fall where it may. When I shot slide film I would spot meter on an area that I knew what the meter should read and set exposure accordingly, and in digital this also yields a good looking sunrise. The histogram, however, is not as far to the right as it could be. Porte
From: Floyd L. Davidson on 13 Oct 2009 20:07
Porte Rouge <porterougeman(a)gmail.com> wrote: >So, with WB all set you take a picture. I gather that you expose to >the right? My sunrise is good example of lighting conditions that >lead to especially washed out colors if you do. How do you adjust the >colors in post or do you just meter for the sunrise and let the >histogram fall where it may. If you don't want any part of the scene to clip, then shoot the sunrize ETTR. It is *absolutely* necessary to post process, where you set the exposure for whatever effect you like. ETTR does *not* cause washed out colors (inappropriate post processing might though). >When I shot slide film I would spot meter >on an area that I knew what the meter should read and set exposure >accordingly, and in digital this also yields a good looking sunrise. >The histogram, however, is not as far to the right as it could be. How can you spot meter on an area that "I knew what the meter would read"??? I don't understand what you mean by that statement. If the histogram is not as far to the right as it could be your image does not have as wide a dynamic range as the camera is capable of recording. The shadow areas will have more noise than if it were exposed per ETTR. If you want any specific *final* tone levels, set it that way in post processing. In essence, in post processing drop the "exposure" to make the editor's histogram show what you think the camera's should have shown absent ETTR adjustments. -- Floyd L. Davidson <http://www.apaflo.com/floyd_davidson> Ukpeagvik (Barrow, Alaska) floyd(a)apaflo.com |