Some raw-related things we often read that are wrong

[Tony Beach]

Below is a short list of things that spring to mind. Please add your favorites.

• The readability of raw files is not guaranteed in future

Do you feel confident that my descendants will be able to use my raw files in 4017AD?

I have no confidence whatsoever that humanity will even exist in 4017 AD. Even if we do manage to make it, how many documents from the time of Christ exist today and how much can we be certain is anything more than myth from that time?

The horrific rate of extinctions of both encoding formats and media forms in just the last 50 years alone makes me at least a little bit wary.

In some ways this is similar to archival print work I do. 99% of it is based on a surviving print as there is no surviving negative.

The chances of a son/daughter or grandson/daughter accessing a computer hard drive that (due to the parents old age) has not been used for a decade can be close to nil.

Think "Cloud computing."

 

[SolB]

issues with bracketing with Auto-ISO. In fact I never even thought of using that type of funtionality. It makes so much sense. I've just used manual ISO compensation to date. Will test to see what results/issues

I will be very much interested to know how it goes.

I will try and verify whether I have some menu item set up incorrectly, but currently when in manual mode (using D810) and auto-iso set; if I set up bracketing for example, -3, 0, +3, instead of ISO changing I get the aperature being set to something crazy like F14.

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http://www.dpreview.com/members/5199381230/galleries

 

[Iliah Borg]

issues with bracketing with Auto-ISO. In fact I never even thought of using that type of funtionality. It makes so much sense. I've just used manual ISO compensation to date. Will test to see what results/issues

I will be very much interested to know how it goes.

I will try and verify whether I have some menu item set up incorrectly, but currently when in manual mode (using D810) and auto-iso set; if I set up bracketing for example, -3, 0, +3, instead of ISO changing I get and aperature being set to something crazy like F14.

Different models with different firmwares do different tricks. On Df - nothing changes at all, on D5 I have aperture changes.

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http://www.libraw.org/

 

[SolB]

issues with bracketing with Auto-ISO. In fact I never even thought of using that type of funtionality. It makes so much sense. I've just used manual ISO compensation to date. Will test to see what results/issues

I will be very much interested to know how it goes.

I will try and verify whether I have some menu item set up incorrectly, but currently when in manual mode (using D810) and auto-iso set; if I set up bracketing for example, -3, 0, +3, instead of ISO changing I get and aperature being set to something crazy like F14.

Different models with different firmwares do different tricks. On Df - nothing changes at all, on D5 I have aperture changes.

--
http://www.libraw.org/

Thanks Iliah. Saved me a lot of time going through my camera settings and the manual.

--
http://www.dpreview.com/members/5199381230/galleries

 

[Iliah Borg]

issues with bracketing with Auto-ISO. In fact I never even thought of using that type of funtionality. It makes so much sense. I've just used manual ISO compensation to date. Will test to see what results/issues

I will be very much interested to know how it goes.

I will try and verify whether I have some menu item set up incorrectly, but currently when in manual mode (using D810) and auto-iso set; if I set up bracketing for example, -3, 0, +3, instead of ISO changing I get and aperature being set to something crazy like F14.

Different models with different firmwares do different tricks. On Df - nothing changes at all, on D5 I have aperture changes.

Thanks Iliah. Saved me a lot of time going through my camera settings and the manual.

I was testing this after performing 'Reset Shooting Options'.

 

[BirgerH]

I think this article addresses what you are asking. Phase One's experience in moving from CCD to CMOS sensors

https://luminous-landscape.com/the-phase-one-iq250-cmos-fully-realized/

Good article.
A couple of quotes from the article.....

“I have fought with color from CMOS cameras for many, many years."

"The quality, especially regarding tonality, dynamic range, and color, of CCD sensors had been untouchable in the world of CMOS sensors."

All this despite the claims from the self-proclaimed experts on this forum

PS. He also has some interesting things to say about the colors from D800 and 5D Mark III.

 

[just Tony]

ancient Greek and ancient Latin (because of their proven track records of already over 2000 years).

I prefer Aramaic, with track record of over 3000 years. It is more raw, too.

I accept that addition

*puts a flower on casket of irony*

Added to the Wrong list.

 

[photoreddi]

Below is a short list of things that spring to mind. Please add your favorites.

• The readability of raw files is not guaranteed in future
• Raw files are dark and green
• Raw is not an image
• JPEGs are 8-bit RGB, and ready for display
• JPEG histogram is a good substitution for raw histogram when it comes to determining the optimal exposure and ETTR
• Image looks dark when it is underexposed
• Sensor gamut
• Sensor colour reproduction
• Exposure triangle (shutter speed / aperture / ISO)
• High ISO noise
• ISO changes sensor sensitivity
• Metering system is calibrated for 18% grey
• Cameramakers cheat with ISO
• CCD is better than CMOS

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http://www.libraw.org/

CCD seems to capture better lightning strike in movie mode than CMOS. I remember old video camera with CCD, never miss a strike or never get half exposed of lightning, just full exposed always while CMOS seems to struggle with lightning shot.

This could be due to the simultaneous recording of all CCD photosites vs. CMOS having a cumulatively added delay between the recording of each successive row of the image (rolling shutter effect). This article elaborates on this in much more detail :

https://www.qimaging.com/ccdorscmos/triggering.php

 

[Tony Beach]

• Raw files are dark and green

Care to elaborate on this? If I understand it correctly, the BFA is more sensitive to the green channel so that under daylight (and similar) light that channel has a higher recorded luminance than the red and blue channels.

To view an image file correctly, we need to respect the explicit and implicit (default) metadata that is associated with the file.

Suppose we have a TIFF in a Lab space. By default, implicitly, we consider its white point to be D50. If the file is recorded for D65, or any other white point that is different from D50, and we ignore this condition while converting it to be displayed, the colour turns out wrong. Same with raw files, if we ignore the white point (given as white balance), the colour on the resulting image looks green or in some other way tinted. If we ignore the black level in a raw file, or set it incorrectly, we will have magentish look, with low contrast due to "magenta veiling". If we ignore the saturation point, we are getting magenta highlights, and so on.

"Dark" is also an issue with implicit metadata being ignored. Raw file is linear, attempting to display it without supplying the correct gamma = 1 results in very compressed shadows.

Here is a short article that covers some of the aspects: https://www.fastrawviewer.com/viewing-raw-is-not-impossible

Thank you for that. I will definitely being reading up on this and may come back with more questions.

Then the issue with the Raw file looking green is because the WB has been set to UniWB in order to get a histogram that more accurately reflects what the sensor is capturing, but we could have an auto or Preset WB recorded in the metadata and applied to the display we see?

 

[Iliah Borg]

the issue with the Raw file looking green is because the WB has been set to UniWB in order to get a histogram that more accurately reflects what the sensor is capturing,

In-camera histogram, yes. But it makes no sense in normal environment not to respect actual white balance and to display green-tinted image.

In the camera, there is absolutely no reason to derive histogram from the JPEG if one wants to see the raw histogram. The whole UniWB workaround was born to compensate for camera design flaw.

Same, it makes no sense to display dark image when ISO is not applied to raw (fully or partially), and the cameras that are designed not to apply all or certain ISO settings to raw data do not show dark images even if ISO is only a tag in the metadata, but not applied to raw data.

In a certain sense white balance is very similar to ISO. ISO acts upon all the channels, while white balance bumps individual channel responses ("sensitivities"), hence the analogy.

On a side note, cameramakers stopped applying white balance to raw data more than 15 years ago, to prevent clipping.

but we could have an auto or Preset WB recorded in the metadata and applied to the display we see?

Some camera models record auto white balance (measured white balance) no matter what. Nikon hide their white balance records, and we do not know how to get that info, or even is it present or not. As I shoot Nikon a lot, I put many hours into deciphering their metadata, but this part I still can't figure out. All we can do here is calculate some auto for proper display.

For those cameras that do record the measured white balance we display raw files taken with UniWB in camera in normal colour -- like it is on the photo of camels here https://www.fastrawviewer.com/blog/FastRawViewer-1-3-9-release

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http://www.libraw.org/

 

[Tony Beach]

I think this article addresses what you are asking. Phase One's experience in moving from CCD to CMOS sensors

https://luminous-landscape.com/the-phase-one-iq250-cmos-fully-realized/

Good article.
A couple of quotes from the article.....

“I have fought with color from CMOS cameras for many, many years."

"The quality, especially regarding tonality, dynamic range, and color, of CCD sensors had been untouchable in the world of CMOS sensors."

All this despite the claims from the self-proclaimed experts on this forum

PS. He also has some interesting things to say about the colors from D800 and 5D Mark III.

Extraordinarily ironic since you're the only one here whose "expertise" is "self-proclaimed." I will take the credentials and words of Iliah, Eric Fossum, Thom Hogan, and practically the entire photography industry over you and your cadre any and every day.

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http://imageevent.com/tonybeach/twelveimages