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08-14-2011, 08:47 PM   #16
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QuoteOriginally posted by JeffJS Quote
Exposing to the left slightly will get you nicely exposed highlights and plenty of room to pull detail out of the shadows if you desire.
I always thought the exact opposite expose for shadow detail and make adjustments in the highlights to bring back details. Made sense to me given the exponential nature of exposure vs the linear sensitivity of the sensor.

08-14-2011, 09:01 PM   #17
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QuoteOriginally posted by GregK8 Quote
I always thought the exact opposite expose for shadow detail and make adjustments in the highlights to bring back details. Made sense to me given the exponential nature of exposure vs the linear sensitivity of the sensor.
The Histogram in the camera and in most software shows the result after gamma correction (lin-to-log conversion) and 8-bit per channel conversion for 24-bit RGB in JPEG. It may also include the affect of the TRC (I only use raw so I'm not sure). If you want to see a 12- or 14-bit linear histogram, use Rawnalyze.

Keeping Rawnalyze alive, a tribute to GaborSch: Open Talk Forum: Digital Photography Review

Dan.

Last edited by dosdan; 08-15-2011 at 04:59 PM.
08-14-2011, 09:18 PM   #18
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QuoteOriginally posted by GregK8 Quote
I always thought the exact opposite expose for shadow detail and make adjustments in the highlights to bring back details. Made sense to me given the exponential nature of exposure vs the linear sensitivity of the sensor.
It's what works for me. I would rather a photo be under exposed than over exposed. If something different works for you, then use it. I don't state it as a hard fast rule but I like to maintain highlight detail and can give up some shadow detail if need be to get it. Clouds in the sky for instance in a photo of my black dog. There is a lot of room on the bottom end with this camera but blown out clouds and other highlights will remain blown. Again, if something different works for you, use it.

For what it's worth, the histogram is basically worthless unless you understand what it is telling you vs the scene you just shot (and so are the 'blinkies'). ETTR is a completely stupid thing to tell someone to do if they are taking a picture of a darkened scene for instance (unless they want to make it not dark). You can get the same information by learning to read the meter vs the scene, Before taking the photo. The histogram is just another tool but like the meter, again, if you don't understand what it is telling you, it's useless. You might as well just bracket 1 or 2 stops on either side and pick the one that suits you best in that case. To use any of it effectively, one must first understand exposure.

One last time for this posting, Use whatever works for you. I'm not going to argue with anyone about it.

08-14-2011, 10:48 PM   #19
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QuoteOriginally posted by JeffJS Quote
There is a lot of room on the bottom end with this camera but blown out clouds and other highlights will remain blown..
Hi
Precisely!
In all of my impoverished meddlings in matters photography I have learned and accepted the fact that in the digital equipment age it is indisputably of greater benefit to expose to the "left" in a situation where great opposites in LUX values present themselves.

This is a particularly relevant and obvious observation when your photographic recording device is a PENTAX K-5.

Greetings

08-15-2011, 12:30 AM   #20
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You are not supposed to blow the highlights when exposing to the right. The idea is to get as much signal as possible, without getting to much.
08-15-2011, 01:08 AM   #21
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A balanced image is good because you have leeway both sides to play around with contrast and clarity settings on the RAW converter. That's why I prefer to expose to the middle (for balanced lighting). Of course, for low key images, the idea is to use negative bias to ETTL and for high key images, positive bias will be needed to ETTR. So it depends on the situation.
08-15-2011, 01:22 AM   #22
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QuoteOriginally posted by JeffJS Quote
For what it's worth, the histogram is basically worthless unless you understand what it is telling you vs the scene you just shot (and so are the 'blinkies'). ETTR is a completely stupid thing to tell someone to do if they are taking a picture of a darkened scene for instance (unless they want to make it not dark). You can get the same information by learning to read the meter vs the scene, Before taking the photo. The histogram is just another tool but like the meter, again, if you don't understand what it is telling you, it's useless. You might as well just bracket 1 or 2 stops on either side and pick the one that suits you best in that case. To use any of it effectively, one must first understand exposure.
The idea is that the signal/noise ratio of your sensor gets better as more light hits it (more signal) so assuming your sensor has a 14 stop dynamic range and your scene has an 8 stop dynamic range (whether it's naturally dark or bright) then you'll get a better quality images using the brightest 8 stops of your camera's DR than the darkest 8 stops.

ETTR has nothing to do with the brightness of the final bitmap image and everything to do with getting the best data into the raw file.

It's not appropriate where your scene has a similar dynamic range to your sensor (14 stops, for the K-5) and it never implies blowing highlights. The in-camera histogram, however, will generally tell you the highlights are blown before they really are (because it's a histogram for a bitmap automatically derived from the raw, not from the raw file itself).
08-15-2011, 10:34 AM   #23
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I really do not see how anyone interested in wildlife photography can get good shots without the history graph showing blow highlights and the subject. Especially with dark birds and white birds and the ambient light. It would almost be impossible to shoot birds without it for me. Many times I will blow the background to oblivion to expose the dark colored bird properly. And the opposite for a light colored bird. If you do not have a guide history of the shot it is almost impossible to be consistent.

Do any of you nature photographers shoot without it? If so I would like to see your shots and get some advice from you.

Thanks

08-15-2011, 03:45 PM   #24
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QuoteOriginally posted by timh Quote
The idea is that the signal/noise ratio of your sensor gets better as more light hits it (more signal) so assuming your sensor has a 14 stop dynamic range and your scene has an 8 stop dynamic range (whether it's naturally dark or bright) then you'll get a better quality images using the brightest 8 stops of your camera's DR than the darkest 8 stops.

ETTR has nothing to do with the brightness of the final bitmap image and everything to do with getting the best data into the raw file.

It's not appropriate where your scene has a similar dynamic range to your sensor (14 stops, for the K-5) and it never implies blowing highlights. The in-camera histogram, however, will generally tell you the highlights are blown before they really are (because it's a histogram for a bitmap automatically derived from the raw, not from the raw file itself).
That is exactly my understanding of it.
You ETTR whether or not you want the scene to be high or lowkey. You then adjust your tonemap afterwards to achieve the desired effect.

I suggest people also read-up on UniWB if they want to ETTR.
08-15-2011, 05:33 PM   #25
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QuoteOriginally posted by Ash Quote
A balanced image is good because you have leeway both sides to play around with contrast and clarity settings on the RAW converter. That's why I prefer to expose to the middle (for balanced lighting). Of course, for low key images, the idea is to use negative bias to ETTL and for high key images, positive bias will be needed to ETTR. So it depends on the situation.
The problem with this approach is that it assumes the histogram is linear when it is not. Remember that as you move from right to left on the histogram, each f-stop records half as much light, and since the sensor is linear, much more detail can be captured when using the right side of the histogram.

Let's assume a dynamic range of 5 stops with the darkest being able to distinguish 128 levels. As we move to the right, the amount of light doubles 2 times by the time we reach the center

128 + 256 + 512 = 896 levels in the three stop range from the far left to the center

Continuing towards the right

512 + 1024 + 2048 = 3584 levels in the three stop range from the center to the right

More levels = more data, more data = more detailed images

Remember, this doesn't mean blow out the highlights, it means lean to the right and dial it back in pp.

Last edited by GregK8; 08-15-2011 at 07:44 PM.
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