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Another ETTR Discussion
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Jan 14, 2019 12:31:45   #
Rich1939 Loc: Pike County Penna.
 
selmslie wrote:
It has all of the characteristics of a JPEG including the 8-bit representation (unless you have a 10-bit display). This is the case even if you eventually export it as a 16-bit TIFF.

But I’ll ask again about the histogram, “Where’s the gap?”


Far better you contact Adobe and ask them why they have chosen to not give us a histogram with sufficient range. When exposing to the right the histogram image will "pile up" on the right side which means the histogram itself lacks sufficient range. Nothing more.
RAW Digger has that range and when reviewing a file that piled up in ACR, in RD the additional information is there to view

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Jan 14, 2019 13:25:19   #
selmslie Loc: Fernandina Beach, FL, USA
 
Rich1939 wrote:
... When exposing to the right the histogram image will "pile up" on the right side which means the histogram itself lacks sufficient range. Nothing more.
RAW Digger has that range and when reviewing a file that piled up in ACR, in RD the additional information is there to view

Exactly the point I have been making!

RawDigger shows the unaltered raw histogram, Adobe and Capture One do not.

If you want to know if the raw highlights are blown you can't determine that from either editor.

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Jan 14, 2019 13:40:09   #
jackm1943 Loc: Omaha, Nebraska
 
I've been experimenting a little with my camera (Canon 6D2) and one lens (Tamron 90 macro), shooting in RAW, and this is what I'm finding: With the histogram crowding the right in Live View, I can increase the exposure up to 2.0 stops with no uncorrectable "blinkies" in ACR. If I go to 2.3 stops, I start getting blowout that won't go away. Against my Pentax spot meter, I get the same thing at 4.0 stops (from Zone 5) and 4.3 stops. I've done this against three scenes with EV's ranging from around 7 to a little over 14 on the Pentax and keep getting the same result. I think this info could be very helpful to me in the future.

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Jan 14, 2019 13:46:38   #
Rich1939 Loc: Pike County Penna.
 
selmslie wrote:
Exactly the point I have been making!

RawDigger shows the unaltered raw histogram, Adobe and Capture One do not.

If you want to know if the raw highlights are blown you can't determine that from either editor.


That is absolutely correct and why everyone recommends ETTR are not shy about strongly saying you have to test every camera. Every

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Jan 14, 2019 13:56:32   #
selmslie Loc: Fernandina Beach, FL, USA
 
Here are the sessions for two images in Capture One with all manual adjustments removed. There is exactly one stop difference in the exposure.

The ETTR exposure has no highlight warnings but the EBTR exposure does.

Note the difference in the editor's histogram.

The raw histograms show no blown highlights in the raw EBTR file even though the stats in the first panel indicate that a small (insignificant) number of green pixels are overexposed.

ETTR 1/250 @ f/11 ISO 100
ETTR 1/250 @ f/11 ISO 100...
(Download)

EBTR 1/125 @ f/11 ISO 100
EBTR 1/125 @ f/11 ISO 100...
(Download)

Raw histograms for the EBTR image
Raw histograms for the EBTR image...
(Download)

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Jan 14, 2019 14:04:02   #
selmslie Loc: Fernandina Beach, FL, USA
 
Rich1939 wrote:
That is absolutely correct and why everyone recommends ETTR are not shy about strongly saying you have to test every camera. Every

Except that not "everyone recommends ETTR".

What most of us recommend is that you avoid blowing the highlights. You can do this very easily by watching for blinkies.

ETTR is only necessary under one condition - that the DR of the scene is very wide (but not too wide) and that you want to fit all of that DR into a single image.

In all other cases you are better off not bothering with ETTR or resorting to bracketed shots and HDR.

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Jan 14, 2019 14:25:53   #
Rich1939 Loc: Pike County Penna.
 
selmslie wrote:
Except that not "everyone recommends ETTR".

What most of us recommend is that you avoid blowing the highlights. You can do this very easily by watching for blinkies.

ETTR is only necessary under one condition - that the DR of the scene is very wide (but not too wide) and that you want to fit all of that DR into a single image.

In all other cases you are better off not bothering with ETTR or resorting to bracketed shots and HDR.


Yup, I left out a word.
everyone who recommends ETTR.

ETTR is a tool. Tools are designed to be used when the job requires them.
Some who use ETTR find it works for them most of the time, some who currently live in constant rain and/or cloudy conditions find it is not currently necessary. Learning a tool and when to use it is considered an intelligent endeavor by most.
Denigrating a tool which has demonstrated its value time after time seems to border on the childish

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Jan 14, 2019 15:25:45   #
selmslie Loc: Fernandina Beach, FL, USA
 
Rich1939 wrote:
... Denigrating a tool which has demonstrated its value time after time seems to border on the childish

That's hardly what I have been doing.

The problem with ETTR has nothing to do with how it is applied. The technique has been described ad nauseam for sixteen years.

But why would someone claim that they know everything about ETTR and EBTR yet refuse to look at the raw histograms?

The most strident proponents seem to be more interested in promoting its use than in understanding the underlying science.

Most of the scenes used to demonstrate the application of ETTR have dynamic ranges that are extremely narrow. That's why we are almost always presented with examples that appear initially to be washed out. It is then a matter of darkening the mid-tones and recovering the highlight information. That can only be accomplished by compressing the DR of the shadows.

But in fact a scene with a very wide DR will initially appear to be very dark and still have the brightest portions at the JPEG or raw file limit. It is then a matter of brightening the mid-tones and recovering the shadow information. That can only be accomplished by compressing the DR of the highlights.

What is often overlooked in the rush to demonstrate it is that there is a real danger of blowing the raw highlights. Intimate knowledge of how a raw file reacts to changes in exposure can be learned only from a product like RawDigger.

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Jan 14, 2019 16:01:02   #
Rich1939 Loc: Pike County Penna.
 
selmslie wrote:
That's hardly what I have been doing.

The problem with ETTR has nothing to do with how it is applied. The technique has been described ad nauseam for sixteen years.

But why would someone claim that they know everything about ETTR and EBTR yet refuse to look at the raw histograms?

The most strident proponents seem to be more interested in promoting its use than in understanding the underlying science.

Most of the scenes used to demonstrate the application of ETTR have dynamic ranges that are extremely narrow. That's why we are almost always presented with examples that appear initially to be washed out. It is then a matter of darkening the mid-tones and recovering the highlight information. That can only be accomplished by compressing the DR of the shadows.

But in fact a scene with a very wide DR will initially appear to be very dark and still have the brightest portions at the JPEG or raw file limit. It is then a matter of brightening the mid-tones and recovering the shadow information. That can only be accomplished by compressing the DR of the highlights.

What is often overlooked in the rush to demonstrate it is that there is a real danger of blowing the raw highlights. Intimate knowledge of how a raw file reacts to changes in exposure can be learned only from a product like RawDigger.
That's hardly what I have been doing. br br The p... (show quote)


“But why would someone claim that they know everything about ETTR and EBTR yet refuse to look at the raw histograms?”
Because, as you have pointed out, the histograms in Photoshop ACR lack the high end range to be of any value there

“What is often overlooked in the rush to demonstrate it is that there is a real danger of blowing the raw highlights.”
Those who promote ETTR rather than overlook that danger, harp on fully testing your camera to greatly reduce that possibility.

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Jan 14, 2019 16:24:05   #
selmslie Loc: Fernandina Beach, FL, USA
 
Rich1939 wrote:
“But why would someone claim that they know everything about ETTR and EBTR yet refuse to look at the raw histograms?”
Because, as you have pointed out, the histograms in Photoshop ACR lack the high end range to be of any value there

But unlike ACR or Capture One histograms, software that actually shows the raw values like RawDigger and FastRawViewer do have value. You can use them to cull out the shots with blown raw highlights and learn about your camera's limitations.
Rich1939 wrote:
“What is often overlooked in the rush to demonstrate it is that there is a real danger of blowing the raw highlights.”
Those who promote ETTR rather than overlook that danger, harp on fully testing your camera to greatly reduce that possibility.

If you watch for the camera's blinkies you only need to understand what triggers them.

It took me less than an hour total to figure this out for my three digital cameras with a little help from RawDigger. That's about 20 minutes per camera. I documented all of this in four threads: Nikon's Blinkies and ETTR, Nikon's Blinkies and ETTR - Followup, Sony's Zebra and ETTR and Sony's Zebra and ETTR - Followup. It took a lot more time to describe what I did than to actually do it.

Those are the only two brands to which I had access but anyone can follow the same procedure with their own camera.

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Jan 14, 2019 17:20:47   #
jackm1943 Loc: Omaha, Nebraska
 
[quote=Rich1939][i]Because, as you have pointed out, the histograms in Photoshop ACR lack the high end range to be of any value there[/quote]

I'm not understanding this. I know that, on my computer at least, the ACR histogram correlates perfectly with blowouts, at least when looking at it the way I do. I drag the lighting slider to the left which will show easily if or where blow outs are present. For me, any vertical line on the right side, large or small, represents some degree of blow out. If present, I choose a different exposure that has none of these vertical lines.

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Jan 14, 2019 17:28:49   #
Rich1939 Loc: Pike County Penna.
 
selmslie wrote:
If you watch for the camera's blinkies you only need to understand what triggers them.

It took me less than an hour total to figure this out for my three digital cameras with a little help from RawDigger. That's about 20 minutes per camera. I documented all of this in four threads: Nikon's Blinkies and ETTR, Nikon's Blinkies and ETTR - Followup, Sony's Zebra and ETTR and Sony's Zebra and ETTR - Followup. It took a lot more time to describe what I did than to actually do it.

Those are the only two brands to which I had access but anyone can follow the same procedure with their own camera.
If you watch for the camera's blinkies you only ne... (show quote)


Raw Digger and Fast Raw Viewer have their place unfortunately that place is not associated with post processing software. Learning your camera’s abilities and its limitations will provide you with the knowledge needed to produce a workable file under adverse lighting conditions. The above programs are “after the fact”, knowing your camera’s shortcomings and strengths ahead of time is far more valuable. And as far as the blinkies go, if you rely on them and limit your exposures according to their settings, you will limit what your camera can do. Leaving money on the table, so to speak. But, you know that.

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Jan 14, 2019 18:16:58   #
jackm1943 Loc: Omaha, Nebraska
 
Rich1939 wrote:
Raw Digger and Fast Raw Viewer have their place unfortunately that place is not associated with post processing software. Learning your camera’s abilities and its limitations will provide you with the knowledge needed to produce a workable file under adverse lighting conditions. The above programs are “after the fact”, knowing your camera’s shortcomings and strengths ahead of time is far more valuable. And as far as the blinkies go, if you rely on them and limit your exposures according to their settings, you will limit what your camera can do. Leaving money on the table, so to speak. But, you know that.
Raw Digger and Fast Raw Viewer have their place un... (show quote)

I don't limit based on the camera's blinkies, but I do with ACR "blinkies" (other than specular hightlights of course) because they indicate unfixable blow outs. In an emergency, one can always paste in some data but it usually doesn't look right. As I mentioned above, ACR blinkies start about two stops above the camera blinkies.

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Jan 14, 2019 18:33:23   #
Rich1939 Loc: Pike County Penna.
 
jackm1943 wrote:
I don't limit based on the camera's blinkies, but I do with ACR "blinkies" (other than specular hightlights of course) because they indicate unfixable blow outs. In an emergency, one can always paste in some data but it usually doesn't look right. As I mentioned above, ACR blinkies start about two stops above the camera blinkies.


By the time you check ACR blinkies it's after the fact. When you have tested your cameras abilities and know how far you can push it then you will be able to prevent blow outs. Not counting specular highlights of course

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Jan 14, 2019 20:18:49   #
selmslie Loc: Fernandina Beach, FL, USA
 
Rich1939 wrote:
Raw Digger and Fast Raw Viewer have their place unfortunately that place is not associated with post processing software. ...

Their place is not with the post processing itself.

But RawDigger is a great aid in learning about exposure and your camera's capabilities.

If you take a lot of images you can save yourself a lot of effort by using Fast Raw Viewer to cull out the images that you should not spend your time on in post processing.

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