Shadow Improvement Vs shutter / FPS modes

[Ephemeris]

Hi folks.

In a recent discussion revolving around the r6ii the use of Bill's PTP shadow improvement data came into conversation.

I've added the r6ii elements to the graph and also the R5 (as that is what we shoot with).

I've been using this data to help understand where, for each mode I can understand the point where changing the ISO setting will have little effect.

If we compare ES to MS for both cameras we see some very different behaviour.

For the r5, we see different behaviour with MS between low FPS and high FPS. What's happening here?

What does this information tell us about the camera in these different modes?

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[John Sheehy]

Hi folks.

In a recent discussion revolving around the r6ii the use of Bill's PTP shadow improvement data came into conversation.

I've added the r6ii elements to the graph and also the R5 (as that is what we shoot with).

I've been using this data to help understand where, for each mode I can understand the point where changing the ISO setting will have little effect.

If we compare ES to MS for both cameras we see some very different behaviour.

For the r5, we see different behaviour with MS between low FPS and high FPS. What's happening here?

What does this information tell us about the camera in these different modes?

https://www.photonstophotos.net/Charts/PDR_Shadow.htm#Canon%20EOS%20R5,Canon%20EOS%20R5(APS-C),Canon%20EOS%20R5(ES),Canon%20EOS%20R5(HS),Canon%20EOS%20R6%20Mark%20II,Canon%20EOS%20R6%20Mark%20II(APS-C),Canon%20EOS%20R6%2

This is a tricky metric. It can create the illusion that "improvement" is a good thing, when it clearly is dependent upon base ISO being bad to have a lot of room for improvement!

The R5 HS uses 13-bit readout, IIRC; that would explain why it falls between normal (14-bit) and ES (12-bit).

 

[Ephemeris]

Hi folks.

In a recent discussion revolving around the r6ii the use of Bill's PTP shadow improvement data came into conversation.

I've added the r6ii elements to the graph and also the R5 (as that is what we shoot with).

I've been using this data to help understand where, for each mode I can understand the point where changing the ISO setting will have little effect.

If we compare ES to MS for both cameras we see some very different behaviour.

For the r5, we see different behaviour with MS between low FPS and high FPS. What's happening here?

What does this information tell us about the camera in these different modes?

https://www.photonstophotos.net/Charts/PDR_Shadow.htm#Canon%20EOS%20R5,Canon%20EOS%20R5(APS-C),Canon%20EOS%20R5(ES),Canon%20EOS%20R5(HS),Canon%20EOS%20R6%20Mark%20II,Canon%20EOS%20R6%20Mark%20II(APS-C),Canon%20EOS%20R6%2

This is a tricky metric. It can create the illusion that "improvement" is a good thing, when it clearly is dependent upon base ISO being bad to have a lot of room for improvement!

Ah yes absolutely. I'm just looking for some flat part, unsure if we can use it for anything else. Perhaps alongside a read noise graph but it's a good point. It is a little counter intuitive.

The R5 HS uses 13-bit readout, IIRC; that would expla

in why it falls between normal (14-bit) and ES (12-bit).

Ah indeed I had forgotten that. I guess it's struggling to shift so much data around.

The R6ii I wonder if it flattens out at such a high ISO with ES bexuase of a bit more noise?

--
Beware of correct answers to wrong questions.
John
http://www.pbase.com/image/55384958.jpg

 

[John Sheehy]

The R6ii I wonder if it flattens out at such a high ISO with ES bexuase of a bit more noise?

That should be due to the ratio of post-gain read noise to other noises used to calculate PDR.

If a hypothetical sensor had no post-gain read noise, then it would be a solid flat line across all ISOs, unless the sensor had dual conversion gain, where there would be two flat zones, the one on the right (higher ISOs) being higher.