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09-09-2008, 07:19 PM   #16
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QuoteOriginally posted by Ole Quote
The adjustments which you mention (Saturation/ Sharpness/Contrast) has no effect whatsoever on RAW files. I must admit that I don't understand that piece of advice which you quote!
I think they realize this, and that is sort of the point. They purport that it DOES affect the jpeg and therefore the histogram displayed on the camera LCD. I believe that the camera always generates some kind of jpeg preview so that it can display it on the screen and generate the histogram etc, and presumably it uses the settings (sat, sharp, contrast etc.) to do this.

So they can control how the histogram shows up without messing up the raw data that they are actually interested in. By changing the settings to exaggerate possible blown highlights etc. they get an "early warning" from the histogram.

09-09-2008, 07:19 PM   #17
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QuoteOriginally posted by jeffkrol Quote
If you think that's intriguing, wait till you find out changing iso is unnecessary....
Re: Sounds wild to me: Nikon D3 - D1 / D700 Forum: Digital Photography Review
Oh, yeah, and when I pushed TriX to 3200 back in the early 1960's, the only thing I had to worry about was adjusting the developing to make sure I had a printable image. This is the same problem re-iterated in technospeak. You will get gobs of digital noise using the suggested procedure, just as I got grain the size of golf balls pushing ASA 160 TriX to 3200 ASA. I'll adjust the ISO, thanks.
09-09-2008, 08:29 PM   #18
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Does anyone actually enjoy all of this? Wrangling over and struggling with techie stuff just takes the edge off photography for me. I love electronica, computers and software in other areas of my life, but dammit I hate the way it intrudes into the aesthetic, etherial process of taking a photo and producing a nice print that I can hang on a wall or give to someone as a gift.
Sigh...
09-09-2008, 09:33 PM   #19
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QuoteOriginally posted by wombat Quote
does anyone actually enjoy all of this? Wrangling over and struggling with techie stuff just takes the edge off photography for me. I love electronica, computers and software in other areas of my life, but dammit i hate the way it intrudes into the aesthetic, etherial process of taking a photo and producing a nice print that i can hang on a wall or give to someone as a gift.
Sigh...
amen!!!!!!

09-09-2008, 10:08 PM   #20
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Some duct tape might work...

QuoteOriginally posted by Wombat Quote
Does anyone actually enjoy all of this? Wrangling over and struggling with techie stuff just takes the edge off photography for me. I love electronica, computers and software in other areas of my life, but dammit I hate the way it intrudes into the aesthetic, etherial process of taking a photo and producing a nice print that I can hang on a wall or give to someone as a gift.
Sigh...
I don't know from etheral, but I do know I'm not getting the dynamic range in images that I want, and I want to know why. If I look at a watch I don't need to kinow how to build it to use it, but I do want to know the time is reasonably accurate and consistent.

I hoped all I had to do was take practice shots, adjust the camera speed/ aperture to bring the camera's LCD histogram to a good middle point and then take the shot -- but now it turns out the histogram I see on the camera bears very little relationship to the RAW data histogram I see in the computer. And that RAW histogram is different than the one when I open the file in Photoshop.

Or maybe I'll just slap a piece of cowboy chrome over the camera LCD, pretend it's a film camera, bracket the hell out of every shot and let it all be a wonderful surprise when I see them in the computer,
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09-09-2008, 11:28 PM   #21
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The histogram is related to the RAW data but only indirectly through jpeg. An image is still an image - so yes, the histogram is relevant. And no, the histogram isn't perfectly matched to the raw data.


Knowing this, we can deliberately change the histogram that is displayed in-camera by altering the settings for the jpeg. The settings only apply to the jpeg thumbnail to display on the camera. The histogram is built on this jpeg (probably alot more efficient due to the decreased size of the image and the fact that you can create that data as you build the jpeg). BTW, this thumbnail image (misnomer because it's a full size image) is embedded into your RAW file (yes, both PEF and DNG). (You can extract just the thumbnail with various developers... eg. "dcraw -e <filename>") In fact, when I'm being lazy, the embedded thumbnail is what I use to prove to myself that the image is worthy of more PP. I've created my own custom scripts to iteratively extract the thumbnail, copy them elsewhere and then duplicate the exif data from the raw file to the thumbnail.


In any case, a high key sunny image, normally exposed (sunny-16, grey card, incident reading, whatever) will show up as a right loaded histogram regardless of whether or not it is RAW or jpeg derived. Conversely, a low-key image will show as a left-loaded histogram. A full frame photo of a red flower will still show more data in the red histogram than in the blue or green. Slight differences aside, the basic image is still the same.


Ok - that's the histogram stuff.



Albert: the suggestion of ETTR is exactly meant to decrease signal-noise ratio.


I think the question of aesthetics and the beauty of the process is a matter of perspective - and perhaps a difference in what we love about photography.


For me, and depending on the image, any information or technique I can use to get greater clarity, beauty, or realism in rendering ... is good information. Furthermore, I enjoy that process. I love that I can make a subtle change to the curves and see the image I had originally envisioned unfold before my eyes. To me. the process of creation only begins at the camera. Getting the most out of that image - getting the best image possible - giving the most beautiful gift image to hang on the wall ... that's all just as fun for me as setting the aperture, shutter speed, waiting for the light, setting up the tripod just so, getting the correct perspective, changing the exposure to suit the image, clicking the shutter, waiting for the MLU timer, etc. All of that is technical too. It's all second nature and i hardly have to think about it now, but it's technical.

There are some photographers who only specialize in the shot. Some artists who only specialize in the processing and print. And some artists who like to see the the process through from the camera setup to the final product.

It's all fun and it's all aesthetic - if you are inclined to see it that way.

Last edited by Frank Fletcher; 09-09-2008 at 11:35 PM. Reason: And no, the histogram isn't perfectly matched to the jpeg. should be: And no, the histogram isn't perfectly matched to raw.
09-10-2008, 12:38 AM   #22
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BTW: I really advise to use the histogram mode that displays all colours separately.
It is possible that one colour is already clipping a lot, but the brightness is not(as it is a function of all colours), so you get no blinkies.
If even one colour channel is clipped you still get weird colours and lose detail.
Brightly coloured flowers in sunlight and skintone in tungsten are the best examples where single channels tend to clip a lot.
09-10-2008, 09:22 AM   #23
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Albert's exposure philosophy - longish

QuoteOriginally posted by Frank Fletcher Quote
Albert: the suggestion of ETTR is exactly meant to decrease signal-noise ratio.
I agree 100 percent. My comment was directed at the linked article, not any posters here. I apologize for not making that as clear as it should have been. I was trying (unsuccessfully) to critique the article in the link. The sum total of the responses in this thread indicate that the article is sheer unadulterated hokum.

My exposure philosophy for digital images:
  1. I have the highlight warnings turned on as my default. I will turn them off sometimes when I am displaying the image for others to critique the composition, but immediately turn them on again. My usual mode is to simply say "ignore the red blinking - that's just for me."
  2. I watch for red blinking highlights. If there are none, I look for yellow highlights, because my image may have been underexposed.
  3. I watch for yellow blinking highlights if there are no red blinkies, particularly. After using cameras with slide film and its associated narrow dynamic range for as long as I have, I can usually tell where the red blinks will be before I press the shutter release. An easily understood example is my living room, on the north side of the house, when I am exposing for the room lighting. The windows will be completely blown out. No problem. I check for blinking yellows in the subject area to make sure I am not underexposing, something very easy to do in this situation.
  4. When I get both sets of blinkies, I know the sensor might be unable to cover the whole dynamic range, and I bring up the four histogram display.
  5. When the histograms look iffy I use one of these two solutions:
    1. I take five exposures at two stop intervals. This is the widest bracketed range available on my k10d without switching to manual exposure. I use this with the idea that I will be using HDR software to make an image with the details in it that I want.
    2. I take three or five exposures at half stop intervals. In this case, I am expecting one of the images to have the shadows and highlights that I want. Although some use one third stop intervals, I find that half stops are good enough for me.
My exposure philosophy for film images: Note that offset bracketing, as described below is not available on all brands of camera. Some cannot bracket around anything but the metered exposure reading. This is a little known advantage to Pentax cameras, film or digital.
  1. Slide film cannot take any over exposure at all, and very little underexposure. If there is the slightest doubt, bracket. For slides I do use 1/3 stop intervals, the smallest available on my MZ-S and SF-1. I may do this combined with a - 1/3 stop exposure compensation, giving me 0, - 1/3 and -2/3, or even combined with - 2/3 to give - 1/3, -2/3 and -1.
  2. Negative flim cannot take underexposure, but will take at least a full stop of overexposure. When in doubt, I bracket at full stop intervals, usually offset to a stop of overexposure. If I set the MZ-S to +1 and then bracket at full stops, I get 0, +1 and +2.
  3. Both types of film may require me to take the images to a professional lab to have things burned and dodged to get the image I want. An alternative now would be to make a high resolution scan of the image(s) and use HDR software.


09-10-2008, 09:35 AM   #24
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QuoteOriginally posted by Canada_Rockies Quote
I agree 100 percent. My comment was directed at the linked article, not any posters here.
Whoops. Didn't catch that. Sorry ... thanks.
09-10-2008, 11:27 AM   #25
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OP response re: color histogram

QuoteOriginally posted by procyon Quote
BTW: I really advise to use the histogram mode that displays all colours separately.
It is possible that one colour is already clipping a lot, but the brightness is not(as it is a function of all colours), so you get no blinkies.
If even one colour channel is clipped you still get weird colours and lose detail.
Brightly coloured flowers in sunlight and skintone in tungsten are the best examples where single channels tend to clip a lot.
Sorry, I don't have an RBG histogram on the K100,
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09-10-2008, 12:44 PM   #26
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OP solution

Thanks folks for all the feedback. I've learned a couple of things and irritated a couple of people. All in all, a good days work.

In any case, henceforward I will apply Occam's Razor to all camera problems -- entia non sunt multiplicanda praeter necessitatem, or, all things being equal the simplest answer is the best answer.

In this case, deal with the camera-RAW histogram disconnect by not using the histogram; I've reset the camera to show the blinkies only in the preview and will just adjust ap/speed/ex comp to the lowest blink rate and bracket that... I think.

Thanks again for all the input,
FHPhotog
09-10-2008, 04:02 PM   #27
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QuoteOriginally posted by FHPhotographer Quote
In this case, deal with the camera-RAW histogram disconnect by not using the histogram; I've reset the camera to show the blinkies only in the preview and will just adjust ap/speed/ex comp to the lowest blink rate and bracket that... I think.

I don't know that anybody is too annoyed.

As should be evident from my posts - I think you'll be losing a valuable tool if you throw out the in-camera histogram. Just to be sure, the blinkies are based on the jpeg as well.

No exposure tools are perfectly accurate. The built in meter is just a guide. A guide that is extremely easy to fool. Part of the art is in being able to take information from all the available sources and adjust as necessary. If you throw out the tools one by one, you'll be left with nothing.

Even Sunny16 doesn't work exactly the same on all cameras as they are all tuned a little differently!!!
09-10-2008, 04:44 PM   #28
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QuoteOriginally posted by Frank Fletcher Quote
I think the question of aesthetics and the beauty of the process is a matter of perspective - and perhaps a difference in what we love about photography.


For me, and depending on the image, any information or technique I can use to get greater clarity, beauty, or realism in rendering ... is good information. Furthermore, I enjoy that process. I love that I can make a subtle change to the curves and see the image I had originally envisioned unfold before my eyes. To me. the process of creation only begins at the camera. Getting the most out of that image - getting the best image possible - giving the most beautiful gift image to hang on the wall ... that's all just as fun for me as setting the aperture, shutter speed, waiting for the light, setting up the tripod just so, getting the correct perspective, changing the exposure to suit the image, clicking the shutter, waiting for the MLU timer, etc. All of that is technical too. It's all second nature and i hardly have to think about it now, but it's technical.

There are some photographers who only specialize in the shot. Some artists who only specialize in the processing and print. And some artists who like to see the the process through from the camera setup to the final product.

It's all fun and it's all aesthetic - if you are inclined to see it that way.
Very nicely expressed, Frank. I appreciate your comments and I'll go away and think some more about my attitude and see if I can find some way, like you, to enjoy the techie stuff. I'm still learning the digital photography game.
Les
09-10-2008, 06:55 PM   #29
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QuoteOriginally posted by Wombat Quote
Does anyone actually enjoy all of this? Wrangling over and struggling with techie stuff just takes the edge off photography for me. I love electronica, computers and software in other areas of my life, but dammit I hate the way it intrudes into the aesthetic, etherial process of taking a photo and producing a nice print that I can hang on a wall or give to someone as a gift.
Sigh...
This is why i like to test the "auto" settings to the max

http://www.kenrockwell.com/tech/histograms.htm
09-12-2008, 04:18 PM   #30
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[QUOTE=FHPhotographer;339507]
In this case, deal with the camera-RAW histogram disconnect by not using the histogram
[/quotes]

That doens't really make much sense. It might not match *exactly*, but it's going to be pretty darned close - a hell of a lot closer than you'll get by ignoring it and guessing - even guessing based on blinkies (which, I'll bet, are also going to be based on the in-camera JPEG conversion engine).
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