GFX 100RF ISO 80 black point subtraction

SrMi said:

JimKasson said:

SrMi said:

If you use automatic metering (aperture priority), ISO 80 clips more highlights (rawdigger), even though live view shows the same clipping.

Images were taken with ISO 80 / f4 / 1.3sec vs. ISO 100 / f4 / 1 sec.

Shooting with the same shutter speed, the difference in the raw histogram between ISO 80 and ISO 100 is much smaller (<10%) than expected. ISO 80 seems to work a bit like extended ISO.

Click to expand...

I don't see the images.

Click to expand...

Sorry for the confusion, I did not attach images. I only wanted to share the exposure and ISO data used in the comparison.

Click to expand...

Here's what I got with the GFX 100 II.







--

JimKasson said:

SrMi said:

JimKasson said:

SrMi said:

If you use automatic metering (aperture priority), ISO 80 clips more highlights (rawdigger), even though live view shows the same clipping.

Images were taken with ISO 80 / f4 / 1.3sec vs. ISO 100 / f4 / 1 sec.

Shooting with the same shutter speed, the difference in the raw histogram between ISO 80 and ISO 100 is much smaller (<10%) than expected. ISO 80 seems to work a bit like extended ISO.

Click to expand...

I don't see the images.

Click to expand...

Sorry for the confusion, I did not attach images. I only wanted to share the exposure and ISO data used in the comparison.

Click to expand...

Here's what I got with the GFX 100 II.

Click to expand...

Here are the Rawdigger histograms. Note how ISO 80 metering hugs the right clipping side and causes more clipping.


ISO 100 / f4 / 1 sec


ISO 80 / f4 / 1.3sec

SrMi said:

JimKasson said:

SrMi said:

JimKasson said:

SrMi said:

If you use automatic metering (aperture priority), ISO 80 clips more highlights (rawdigger), even though live view shows the same clipping.

Images were taken with ISO 80 / f4 / 1.3sec vs. ISO 100 / f4 / 1 sec.

Shooting with the same shutter speed, the difference in the raw histogram between ISO 80 and ISO 100 is much smaller (<10%) than expected. ISO 80 seems to work a bit like extended ISO.

Click to expand...

I don't see the images.

Click to expand...

Sorry for the confusion, I did not attach images. I only wanted to share the exposure and ISO data used in the comparison.

Click to expand...

Here's what I got with the GFX 100 II.

Click to expand...

Here are the Rawdigger histograms. Note how ISO 80 metering hugs the right clipping side and causes more clipping.


ISO 100 / f4 / 1 sec


ISO 80 / f4 / 1.3sec

Click to expand...

While the LV histogram is identical with ISO 80 and ISO 100 (A-priority metering), the raw histogram of ISO 80 is shifted to the right. My conclusion is that one should avoid ISO 80 as histogram and clippings are misleading.

jhunna said:

AndyGordon said:

dbateman said:

Makes the most sense for this camera.

Remember its really for jpeg shooters. You set the crop, zoom and all the final settings in camera.

This camera is configured not for Raw only.

Click to expand...

Respectfully no. It can be used in that way as any camera can. I would view this as a multi faceted camera with:

• A camera with easy access to compositional aids
• A camera with the ability to capture full raw images at a 35mm fov
• A camera that can act as a second camera to an ILC camera
• A travel camera
• A whatever you want to do single lens camera

I do not believe it is 'just' a jpeg camera, that's rather over simplifying things

Click to expand...

While I agree with everything you said, I do think in camera developing is one of the reasons for owning this camera, be it jpeg/heif or even tiff. dbateman didn't say it was "just" a jpeg camera, but for jpeg shooters, and I agree with that also.

I try to get my final file in camera while using the easier to edit RAW file as a failsafe.

Click to expand...

Thank you. Yes I didn't say just jpeg.

I always save as jpeg + raw and many should do the same. I do it to get a decent preview on the back screen. For the RF camera you should do it in case you have an all star image and want to do a deeper dive edit in the future.

dbateman said:

jhunna said:

AndyGordon said:

dbateman said:

Makes the most sense for this camera.

Remember its really for jpeg shooters. You set the crop, zoom and all the final settings in camera.

This camera is configured not for Raw only.

Click to expand...

Respectfully no. It can be used in that way as any camera can. I would view this as a multi faceted camera with:

• A camera with easy access to compositional aids
• A camera with the ability to capture full raw images at a 35mm fov
• A camera that can act as a second camera to an ILC camera
• A travel camera
• A whatever you want to do single lens camera

I do not believe it is 'just' a jpeg camera, that's rather over simplifying things

Click to expand...

While I agree with everything you said, I do think in camera developing is one of the reasons for owning this camera, be it jpeg/heif or even tiff. dbateman didn't say it was "just" a jpeg camera, but for jpeg shooters, and I agree with that also.

I try to get my final file in camera while using the easier to edit RAW file as a failsafe.

Click to expand...

Thank you. Yes I didn't say just jpeg.

I always save as jpeg + raw and many should do the same. I do it to get a decent preview on the back screen. For the RF camera you should do it in case you have an all star image and want to do a deeper dive edit in the future.

Click to expand...

Shooting GFX100RF with JPEGs is a "must" as aspect ratios cannot be changed if you shoot only raw.

SrMi said:

SrMi said:

JimKasson said:

SrMi said:

JimKasson said:

SrMi said:

If you use automatic metering (aperture priority), ISO 80 clips more highlights (rawdigger), even though live view shows the same clipping.

Images were taken with ISO 80 / f4 / 1.3sec vs. ISO 100 / f4 / 1 sec.

Shooting with the same shutter speed, the difference in the raw histogram between ISO 80 and ISO 100 is much smaller (<10%) than expected. ISO 80 seems to work a bit like extended ISO.

Click to expand...

I don't see the images.

Click to expand...

Sorry for the confusion, I did not attach images. I only wanted to share the exposure and ISO data used in the comparison.

Click to expand...

Here's what I got with the GFX 100 II.

Click to expand...

Here are the Rawdigger histograms. Note how ISO 80 metering hugs the right clipping side and causes more clipping.


ISO 100 / f4 / 1 sec


ISO 80 / f4 / 1.3sec

Click to expand...

While the LV histogram is identical with ISO 80 and ISO 100 (A-priority metering), the raw histogram of ISO 80 is shifted to the right. My conclusion is that one should avoid ISO 80 as histogram and clippings are misleading.

Click to expand...

So are we implying that ISO 80 is basically ISO 100 and EC +1/3? Photonstophotos implies about a 1/3 stop more DR at 80 than 100.

Is that at the expense of more clipping or is it real?

Is this an issue with the in camera histogram which is based on jpeg rather than real.

ISO 80 is somewhat useless if it promotes additional clipping.

--
"The winds of heaven is that which blows between a horse's ears," Bedouin Proverb
__
Truman
DPR Co-MOD - Fuji X
www.tprevattimages.com

Truman Prevatt said:

SrMi said:

SrMi said:

JimKasson said:

SrMi said:

JimKasson said:

SrMi said:

If you use automatic metering (aperture priority), ISO 80 clips more highlights (rawdigger), even though live view shows the same clipping.

Images were taken with ISO 80 / f4 / 1.3sec vs. ISO 100 / f4 / 1 sec.

Shooting with the same shutter speed, the difference in the raw histogram between ISO 80 and ISO 100 is much smaller (<10%) than expected. ISO 80 seems to work a bit like extended ISO.

Click to expand...

I don't see the images.

Click to expand...

Sorry for the confusion, I did not attach images. I only wanted to share the exposure and ISO data used in the comparison.

Click to expand...

Here's what I got with the GFX 100 II.

Click to expand...

Here are the Rawdigger histograms. Note how ISO 80 metering hugs the right clipping side and causes more clipping.


ISO 100 / f4 / 1 sec


ISO 80 / f4 / 1.3sec

Click to expand...

While the LV histogram is identical with ISO 80 and ISO 100 (A-priority metering), the raw histogram of ISO 80 is shifted to the right. My conclusion is that one should avoid ISO 80 as histogram and clippings are misleading.

Click to expand...

So are we implying that ISO 80 is basically ISO 100 and EC +1/3?

Click to expand...

It's not that simple because of the difference in black point subtraction.

Truman Prevatt said:

Photonstophotos implies about a 1/3 stop more DR at 80 than 100.

Click to expand...

Some of the DR delta is illusionary because of the black point subtraction at ISO 80 removes half the read noise.

Truman Prevatt said:

Is that at the expense of more clipping or is it real?

Is this an issue with the in camera histogram which is based on jpeg rather than real.

Click to expand...

None of this has anything to do with the in-camera histogram.

Truman Prevatt said:

ISO 80 is somewhat useless if it promotes additional clipping.

Click to expand...

--

Truman Prevatt said:

SrMi said:

SrMi said:

JimKasson said:

SrMi said:

JimKasson said:

SrMi said:

If you use automatic metering (aperture priority), ISO 80 clips more highlights (rawdigger), even though live view shows the same clipping.

Images were taken with ISO 80 / f4 / 1.3sec vs. ISO 100 / f4 / 1 sec.

Shooting with the same shutter speed, the difference in the raw histogram between ISO 80 and ISO 100 is much smaller (<10%) than expected. ISO 80 seems to work a bit like extended ISO.

Click to expand...

I don't see the images.

Click to expand...

Sorry for the confusion, I did not attach images. I only wanted to share the exposure and ISO data used in the comparison.

Click to expand...

Here's what I got with the GFX 100 II.

Click to expand...

Here are the Rawdigger histograms. Note how ISO 80 metering hugs the right clipping side and causes more clipping.


ISO 100 / f4 / 1 sec


ISO 80 / f4 / 1.3sec

Click to expand...

While the LV histogram is identical with ISO 80 and ISO 100 (A-priority metering), the raw histogram of ISO 80 is shifted to the right. My conclusion is that one should avoid ISO 80 as histogram and clippings are misleading.

Click to expand...

So are we implying that ISO 80 is basically ISO 100 and EC +1/3? Photonstophotos implies about a 1/3 stop more DR at 80 than 100.

Is that at the expense of more clipping or is it real?

Is this an issue with the in camera histogram which is based on jpeg rather than real.

ISO 80 is somewhat useless if it promotes additional clipping.

Click to expand...

Note that ISO 80 images have a different BaselineExposure value than ISO 100 or 200:

ISO 80: BaselineExposure: -0.01

ISO 100, ISO 200: BaselineExposure: +.22

This makes the JPEG histogram different for exposure at ISO 80 than at other ISOs.

JimKasson said:

Truman Prevatt said:

SrMi said:

SrMi said:

JimKasson said:

SrMi said:

JimKasson said:

SrMi said:

If you use automatic metering (aperture priority), ISO 80 clips more highlights (rawdigger), even though live view shows the same clipping.

Images were taken with ISO 80 / f4 / 1.3sec vs. ISO 100 / f4 / 1 sec.

Shooting with the same shutter speed, the difference in the raw histogram between ISO 80 and ISO 100 is much smaller (<10%) than expected. ISO 80 seems to work a bit like extended ISO.

Click to expand...

I don't see the images.

Click to expand...

Sorry for the confusion, I did not attach images. I only wanted to share the exposure and ISO data used in the comparison.

Click to expand...

Here's what I got with the GFX 100 II.

Click to expand...

Here are the Rawdigger histograms. Note how ISO 80 metering hugs the right clipping side and causes more clipping.


ISO 100 / f4 / 1 sec


ISO 80 / f4 / 1.3sec

Click to expand...

While the LV histogram is identical with ISO 80 and ISO 100 (A-priority metering), the raw histogram of ISO 80 is shifted to the right. My conclusion is that one should avoid ISO 80 as histogram and clippings are misleading.

Click to expand...

So are we implying that ISO 80 is basically ISO 100 and EC +1/3?

Click to expand...

It's not that simple because of the difference in black point subtraction.

JimKasson said:

Photonstophotos implies about a 1/3 stop more DR at 80 than 100.

Click to expand...

Some of the DR delta is illusionary because of the black point subtraction at ISO 80 removes half the read noise.

JimKasson said:

Is that at the expense of more clipping or is it real?

Is this an issue with the in camera histogram which is based on jpeg rather than real.

Click to expand...

None of this has anything to do with the in-camera histogram.

Click to expand...

BaselineExposure is different. ISO 80 JPEGs shown in the camera are darkened when compared to ISO 100 and higher. This means that the JPEG histogram has a different relation to the raw histogram at ISO 80 than at ISO 100 or higher.

JimKasson said:

JimKasson said:

ISO 80 is somewhat useless if it promotes additional clipping.

Click to expand...

Click to expand...

SrMi said:

Truman Prevatt said:

SrMi said:

SrMi said:

JimKasson said:

SrMi said:

JimKasson said:

SrMi said:

If you use automatic metering (aperture priority), ISO 80 clips more highlights (rawdigger), even though live view shows the same clipping.

Images were taken with ISO 80 / f4 / 1.3sec vs. ISO 100 / f4 / 1 sec.

Shooting with the same shutter speed, the difference in the raw histogram between ISO 80 and ISO 100 is much smaller (<10%) than expected. ISO 80 seems to work a bit like extended ISO.

Click to expand...

I don't see the images.

Click to expand...

Sorry for the confusion, I did not attach images. I only wanted to share the exposure and ISO data used in the comparison.

Click to expand...

Here's what I got with the GFX 100 II.

Click to expand...

Here are the Rawdigger histograms. Note how ISO 80 metering hugs the right clipping side and causes more clipping.


ISO 100 / f4 / 1 sec


ISO 80 / f4 / 1.3sec

Click to expand...

While the LV histogram is identical with ISO 80 and ISO 100 (A-priority metering), the raw histogram of ISO 80 is shifted to the right. My conclusion is that one should avoid ISO 80 as histogram and clippings are misleading.

Click to expand...

So are we implying that ISO 80 is basically ISO 100 and EC +1/3? Photonstophotos implies about a 1/3 stop more DR at 80 than 100.

Is that at the expense of more clipping or is it real?

Is this an issue with the in camera histogram which is based on jpeg rather than real.

ISO 80 is somewhat useless if it promotes additional clipping.

Click to expand...

Note that ISO 80 images have a different BaselineExposure value than ISO 100 or 200:

ISO 80: BaselineExposure: -0.01

ISO 100, ISO 200: BaselineExposure: +.22

This makes the JPEG histogram different for exposure at ISO 80 than at other ISOs.

Click to expand...

This is getting uglier and uglier.

--

SrMi said:

JimKasson said:

Truman Prevatt said:

SrMi said:

SrMi said:

JimKasson said:

SrMi said:

JimKasson said:

SrMi said:

If you use automatic metering (aperture priority), ISO 80 clips more highlights (rawdigger), even though live view shows the same clipping.

Images were taken with ISO 80 / f4 / 1.3sec vs. ISO 100 / f4 / 1 sec.

Shooting with the same shutter speed, the difference in the raw histogram between ISO 80 and ISO 100 is much smaller (<10%) than expected. ISO 80 seems to work a bit like extended ISO.

Click to expand...

I don't see the images.

Click to expand...

Sorry for the confusion, I did not attach images. I only wanted to share the exposure and ISO data used in the comparison.

Click to expand...

Here's what I got with the GFX 100 II.

Click to expand...

Here are the Rawdigger histograms. Note how ISO 80 metering hugs the right clipping side and causes more clipping.


ISO 100 / f4 / 1 sec


ISO 80 / f4 / 1.3sec

Click to expand...

While the LV histogram is identical with ISO 80 and ISO 100 (A-priority metering), the raw histogram of ISO 80 is shifted to the right. My conclusion is that one should avoid ISO 80 as histogram and clippings are misleading.

Click to expand...

So are we implying that ISO 80 is basically ISO 100 and EC +1/3?

Click to expand...

It's not that simple because of the difference in black point subtraction.

SrMi said:

Photonstophotos implies about a 1/3 stop more DR at 80 than 100.

Click to expand...

Some of the DR delta is illusionary because of the black point subtraction at ISO 80 removes half the read noise.

SrMi said:

Is that at the expense of more clipping or is it real?

Is this an issue with the in camera histogram which is based on jpeg rather than real.

Click to expand...

None of this has anything to do with the in-camera histogram.

Click to expand...

BaselineExposure is different. ISO 80 JPEGs shown in the camera are darkened when compared to ISO 100 and higher. This means that the JPEG histogram has a different relation to the raw histogram at ISO 80 than at ISO 100 or higher.

Click to expand...

Gotcha. But that doesn't affect your experiment, or mine either.

SrMi said:

SrMi said:

SrMi said:

ISO 80 is somewhat useless if it promotes additional clipping.

Click to expand...

Click to expand...

Click to expand...

--

JimKasson said:

SrMi said:

JimKasson said:

Truman Prevatt said:

SrMi said:

SrMi said:

JimKasson said:

SrMi said:

JimKasson said:

SrMi said:

If you use automatic metering (aperture priority), ISO 80 clips more highlights (rawdigger), even though live view shows the same clipping.

Images were taken with ISO 80 / f4 / 1.3sec vs. ISO 100 / f4 / 1 sec.

Shooting with the same shutter speed, the difference in the raw histogram between ISO 80 and ISO 100 is much smaller (<10%) than expected. ISO 80 seems to work a bit like extended ISO.

Click to expand...

I don't see the images.

Click to expand...

Sorry for the confusion, I did not attach images. I only wanted to share the exposure and ISO data used in the comparison.

Click to expand...

Here's what I got with the GFX 100 II.

Click to expand...

Here are the Rawdigger histograms. Note how ISO 80 metering hugs the right clipping side and causes more clipping.


ISO 100 / f4 / 1 sec


ISO 80 / f4 / 1.3sec

Click to expand...

While the LV histogram is identical with ISO 80 and ISO 100 (A-priority metering), the raw histogram of ISO 80 is shifted to the right. My conclusion is that one should avoid ISO 80 as histogram and clippings are misleading.

Click to expand...

So are we implying that ISO 80 is basically ISO 100 and EC +1/3?

Click to expand...

It's not that simple because of the difference in black point subtraction.

JimKasson said:

Photonstophotos implies about a 1/3 stop more DR at 80 than 100.

Click to expand...

Some of the DR delta is illusionary because of the black point subtraction at ISO 80 removes half the read noise.

JimKasson said:

Is that at the expense of more clipping or is it real?

Is this an issue with the in camera histogram which is based on jpeg rather than real.

Click to expand...

None of this has anything to do with the in-camera histogram.

Click to expand...

BaselineExposure is different. ISO 80 JPEGs shown in the camera are darkened when compared to ISO 100 and higher. This means that the JPEG histogram has a different relation to the raw histogram at ISO 80 than at ISO 100 or higher.

Click to expand...

Gotcha. But that doesn't affect your experiment, or mine either.

Click to expand...

It affects practical usage when using JPEG baaed highlight clipping or histogram to set exposure.

JimKasson said:

JimKasson said:

JimKasson said:

JimKasson said:

ISO 80 is somewhat useless if it promotes additional clipping.

Click to expand...

Click to expand...

Click to expand...

--
https://blog.kasson.com

Click to expand...

SrMi said:

JimKasson said:

SrMi said:

JimKasson said:

Truman Prevatt said:

SrMi said:

SrMi said:

JimKasson said:

SrMi said:

JimKasson said:

SrMi said:

If you use automatic metering (aperture priority), ISO 80 clips more highlights (rawdigger), even though live view shows the same clipping.

Images were taken with ISO 80 / f4 / 1.3sec vs. ISO 100 / f4 / 1 sec.

Shooting with the same shutter speed, the difference in the raw histogram between ISO 80 and ISO 100 is much smaller (<10%) than expected. ISO 80 seems to work a bit like extended ISO.

Click to expand...

I don't see the images.

Click to expand...

Sorry for the confusion, I did not attach images. I only wanted to share the exposure and ISO data used in the comparison.

Click to expand...

Here's what I got with the GFX 100 II.

Click to expand...

Here are the Rawdigger histograms. Note how ISO 80 metering hugs the right clipping side and causes more clipping.


ISO 100 / f4 / 1 sec


ISO 80 / f4 / 1.3sec

Click to expand...

While the LV histogram is identical with ISO 80 and ISO 100 (A-priority metering), the raw histogram of ISO 80 is shifted to the right. My conclusion is that one should avoid ISO 80 as histogram and clippings are misleading.

Click to expand...

So are we implying that ISO 80 is basically ISO 100 and EC +1/3?

Click to expand...

It's not that simple because of the difference in black point subtraction.

SrMi said:

Photonstophotos implies about a 1/3 stop more DR at 80 than 100.

Click to expand...

Some of the DR delta is illusionary because of the black point subtraction at ISO 80 removes half the read noise.

SrMi said:

Is that at the expense of more clipping or is it real?

Is this an issue with the in camera histogram which is based on jpeg rather than real.

Click to expand...

None of this has anything to do with the in-camera histogram.

Click to expand...

BaselineExposure is different. ISO 80 JPEGs shown in the camera are darkened when compared to ISO 100 and higher. This means that the JPEG histogram has a different relation to the raw histogram at ISO 80 than at ISO 100 or higher.

Click to expand...

Gotcha. But that doesn't affect your experiment, or mine either.

Click to expand...

It affects practical usage when using JPEG baaed highlight clipping or histogram to set exposure.

Click to expand...

No argument there, and one more reason to avoid ISO 80. Thanks for your research on this.

SrMi said:

SrMi said:

SrMi said:

SrMi said:

SrMi said:

ISO 80 is somewhat useless if it promotes additional clipping.

Click to expand...

Click to expand...

Click to expand...

Click to expand...

Click to expand...

--

Thanks, Jim for all your feedback on the GFX100RF. Would you then say using ISO 80 or 100 for optimal results in RAW? The "Mathphotographer" on Youtube compared the camera to his Q3 and Q43 using ISO 100 instead of the 'official' base ISO of 80.

eliehbk said:

Thanks, Jim for all your feedback on the GFX100RF. Would you then say using ISO 80 or 100 for optimal results in RAW? The "Mathphotographer" on Youtube compared the camera to his Q3 and Q43 using ISO 100 instead of the 'official' base ISO of 80.

Click to expand...

As Jim has shown, ISO80 on the RF is somewhat special, and so is ISO 50 on the Leica Q2/Q3.

I would have compared ISO 80 against ISO 50, and a proper comparison would be 80/50, 400, 800, 1600 and 6400 ISO (the latter a consequence of the f/4 lens and no IBIS/OIS).

So which one to use to have the most dynamic range and amount of noise?

eliehbk said:

So which one to use to have the most dynamic range and amount of noise?

Click to expand...

I second that question. P2P shows additional about 1/3 a stops at ISO 80. On the other hand the histograms shown point to about 1/3 stop shift toward highlight end as a result of the metering. So the question seems to be realizing that and using a -1/3 EC to shift the exposure down by 1/3 of a stop to compensate from the metering and the way the histogram is calculated at ISO 80 result the in slight amount of DR shown in Photons2Photos?

As an aside on the 100RF I modulate the ISO with the front wheel, keeping it as low as possible while meeting my requirement for shutter speed and aperture. I don't avoid 80 and I often find Fuji is not quite as aggressive as I would like in protecting highlights and often use -1/3 EC at all ISO's. I actually would like Fuji to implement a second metering mode similar to that on my Z8 with a little more highlight protection. They don't, I do it myself. I've not notice any negative impact on shooting ISO 80. I might be missing something or might not have run into a scene where there would be an impact.

So while charts and histograms are nice, question arise when two different sources show charts that point to what seems to be contradictory conclusions. What does it mean using the camera in the wild?

Truman Prevatt said:

eliehbk said:

So which one to use to have the most dynamic range and amount of noise?

Click to expand...

I second that question. P2P shows additional about 1/3 a stops at ISO 80. On the other hand the histograms shown point to about 1/3 stop shift toward highlight end as a result of the metering. So the question seems to be realizing that and using a -1/3 EC to shift the exposure down by 1/3 of a stop to compensate from the metering and the way the histogram is calculated at ISO 80 result the in slight amount of DR shown in Photons2Photos?

Click to expand...

Which DR metric are you referring to? Bill gives you metrics that allow at least two.

Truman Prevatt said:

As an aside on the 100RF I modulate the ISO with the front wheel, keeping it as low as possible while meeting my requirement for shutter speed and aperture. I don't avoid 80 and I often find Fuji is not quite as aggressive as I would like in protecting highlights and often use -1/3 EC at all ISO's. I actually would like Fuji to implement a second metering mode similar to that on my Z8 with a little more highlight protection. They don't, I do it myself. I've not notice any negative impact on shooting ISO 80. I might be missing something or might not have run into a scene where there would be an impact.

So while charts and histograms are nice, question arise when two different sources show charts that point to what seems to be contradictory conclusions. What does it mean using the camera in the wild?

Click to expand...

Can you be explicit and detailed about the contradictions you see? Bill and I are generally pretty much in agreement.

JimKasson said:

Truman Prevatt said:

eliehbk said:

So which one to use to have the most dynamic range and amount of noise?

Click to expand...

I second that question. P2P shows additional about 1/3 a stops at ISO 80. On the other hand the histograms shown point to about 1/3 stop shift toward highlight end as a result of the metering. So the question seems to be realizing that and using a -1/3 EC to shift the exposure down by 1/3 of a stop to compensate from the metering and the way the histogram is calculated at ISO 80 result the in slight amount of DR shown in Photons2Photos?

Click to expand...

Which DR metric are you referring to? Bill gives you metrics that allow at least two.

JimKasson said:

As an aside on the 100RF I modulate the ISO with the front wheel, keeping it as low as possible while meeting my requirement for shutter speed and aperture. I don't avoid 80 and I often find Fuji is not quite as aggressive as I would like in protecting highlights and often use -1/3 EC at all ISO's. I actually would like Fuji to implement a second metering mode similar to that on my Z8 with a little more highlight protection. They don't, I do it myself. I've not notice any negative impact on shooting ISO 80. I might be missing something or might not have run into a scene where there would be an impact.

So while charts and histograms are nice, question arise when two different sources show charts that point to what seems to be contradictory conclusions. What does it mean using the camera in the wild?

Click to expand...

Can you be explicit and detailed about the contradictions you see? Bill and I are generally pretty much in agreement.

Click to expand...

The photonstophotos chart givens a PDR of 12.55 at ISO 80 and 12.29 at ISO 100, or a little less than 1/3 stop more DR for that sensor. The histograms shown in one of the post shows a slight shift toward the highlight ( a little more prone to clip) at ISO80 than ISO100. The shift in the histogram can be eliminated by the good old Fuji -1/3 EC which can be common. is that an artifact in the testing protocol of photonstophotos?

So my question is does the ISO 80 produce slightly more DR or is that an artifact in the testing protocol of photonstophotos? If this shift is understood and calibrated for in the metering and calculating the exposure - is there a reason to avoid ISO 80. if there DR is the same at 100 and 80, then that would be such a reason.

Truman Prevatt said:

JimKasson said:

Truman Prevatt said:

eliehbk said:

So which one to use to have the most dynamic range and amount of noise?

Click to expand...

I second that question. P2P shows additional about 1/3 a stops at ISO 80. On the other hand the histograms shown point to about 1/3 stop shift toward highlight end as a result of the metering. So the question seems to be realizing that and using a -1/3 EC to shift the exposure down by 1/3 of a stop to compensate from the metering and the way the histogram is calculated at ISO 80 result the in slight amount of DR shown in Photons2Photos?

Click to expand...

Which DR metric are you referring to? Bill gives you metrics that allow at least two.

Truman Prevatt said:

As an aside on the 100RF I modulate the ISO with the front wheel, keeping it as low as possible while meeting my requirement for shutter speed and aperture. I don't avoid 80 and I often find Fuji is not quite as aggressive as I would like in protecting highlights and often use -1/3 EC at all ISO's. I actually would like Fuji to implement a second metering mode similar to that on my Z8 with a little more highlight protection. They don't, I do it myself. I've not notice any negative impact on shooting ISO 80. I might be missing something or might not have run into a scene where there would be an impact.

So while charts and histograms are nice, question arise when two different sources show charts that point to what seems to be contradictory conclusions. What does it mean using the camera in the wild?

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Can you be explicit and detailed about the contradictions you see? Bill and I are generally pretty much in agreement.

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The photonstophotos chart givens a PDR of 12.55 at ISO 80 and 12.29 at ISO 100, or a little less than 1/3 stop more DR for that sensor.

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So your chosen metric for DR is PDR? That's a pretty good one.

Truman Prevatt said:

The histograms shown in one of the post shows a slight shift toward the highlight ( a little more prone to clip) at ISO80 than ISO100.

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That is not taken into account in photon transfer functions like the ones that Bill and I calculate.

Truman Prevatt said:

The shift in the histogram can be eliminated by the good old Fuji -1/3 EC which can be common. is that an artifact in the testing protocol of photonstophotos?

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See above.

Truman Prevatt said:

So my question is does the ISO 80 produce slightly more DR or is that an artifact in the testing protocol of photonstophotos?

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It does, but it does it with a (cheap, IMO) trick -- jettisoning half the read noise -- that is not reflective of a read noise difference after demosaicing and black point compensation in the raw converter.

Truman Prevatt said:

If this shift is understood and calibrated for in the metering and calculating the exposure - is there a reason to avoid ISO 80. if there DR is the same at 100 and 80, then that would be such a reason.

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The FWC is higher at ISO 80, so that could be reason to use it if you are OK with what it does to the black point.