A1 dual native ISO values?

[DerrickRR]

I know with the A7Siii it is said the second native ISO kicks in 4-1/3 stops above the base ISO.

Does the 4-1/3 formula not apply to the A1? I’ve seen in a number of places that the second native ISO kicks in at 500 ISO for stills. So with the base ISO being 100, this comes out to be 2-1/3 stops. Does this same math apply to video? PP11 (S-Cinetone) has a base ISO of 125. Using the 2-1/3 stops formula would yield a second native ISO of 640.

Am I correct or am I missing something?

 

[No account anymore]

I know with the A7Siii it is said the second native ISO kicks in 4-1/3 stops above the base ISO.

Does the 4-1/3 formula not apply to the A1? I’ve seen in a number of places that the second native ISO kicks in at 500 ISO for stills. So with the base ISO being 100, this comes out to be 2-1/3 stops. Does this same math apply to video? PP11 (S-Cinetone) has a base ISO of 125. Using the 2-1/3 stops formula would yield a second native ISO of 640.

Am I correct or am I missing something?

Go to photonstophotos.net, open Photographic Dynamic Range versus ISO setting, and chose Sony ILCE 1. You will find the seccond gain level where the curve raise at about ISO 500.

 

[DerrickRR]

I know with the A7Siii it is said the second native ISO kicks in 4-1/3 stops above the base ISO.

Does the 4-1/3 formula not apply to the A1? I’ve seen in a number of places that the second native ISO kicks in at 500 ISO for stills. So with the base ISO being 100, this comes out to be 2-1/3 stops. Does this same math apply to video? PP11 (S-Cinetone) has a base ISO of 125. Using the 2-1/3 stops formula would yield a second native ISO of 640.

Am I correct or am I missing something?

Go to photonstophotos.net, open Photographic Dynamic Range versus ISO setting, and chose Sony ILCE 1. You will find the seccond gain level where the curve raise at about ISO 500.

Thank you. I’ve seen that but what about the various video picture profiles? Do I simply apply the 2-1/3 stops rule?

 

[AlephNull]

I know with the A7Siii it is said the second native ISO kicks in 4-1/3 stops above the base ISO.

Does the 4-1/3 formula not apply to the A1? I’ve seen in a number of places that the second native ISO kicks in at 500 ISO for stills. So with the base ISO being 100, this comes out to be 2-1/3 stops. Does this same math apply to video? PP11 (S-Cinetone) has a base ISO of 125. Using the 2-1/3 stops formula would yield a second native ISO of 640.

Am I correct or am I missing something?

There isn't a rule. The point at which the second gain setting kicks in is determined by the designer, not by some general property of sensor design.

There are dual gain sensors with an base ISO of 100, where the second gain setting starts at 400, others at 600ish. The A1 is 500.

I don't know if you can apply a proportion to get the start of dual gain in S-Cinetone - someone else may know, or it may have to be measured.

 

[Charles Hull]

I know with the A7Siii it is said the second native ISO kicks in 4-1/3 stops above the base ISO.

Does the 4-1/3 formula not apply to the A1? I’ve seen in a number of places that the second native ISO kicks in at 500 ISO for stills. So with the base ISO being 100, this comes out to be 2-1/3 stops. Does this same math apply to video? PP11 (S-Cinetone) has a base ISO of 125. Using the 2-1/3 stops formula would yield a second native ISO of 640.

Am I correct or am I missing something?

Go to photonstophotos.net, open Photographic Dynamic Range versus ISO setting, and chose Sony ILCE 1. You will find the seccond gain level where the curve raise at about ISO 500.

Thank you. I’ve seen that but what about the various video picture profiles? Do I simply apply the 2-1/3 stops rule?

Yes,

S-Cinetone, 125 and 640 (nearest)

Slog3, 800 and 4000

 

[DerrickRR]

I know with the A7Siii it is said the second native ISO kicks in 4-1/3 stops above the base ISO.

Does the 4-1/3 formula not apply to the A1? I’ve seen in a number of places that the second native ISO kicks in at 500 ISO for stills. So with the base ISO being 100, this comes out to be 2-1/3 stops. Does this same math apply to video? PP11 (S-Cinetone) has a base ISO of 125. Using the 2-1/3 stops formula would yield a second native ISO of 640.

Am I correct or am I missing something?

Go to photonstophotos.net, open Photographic Dynamic Range versus ISO setting, and chose Sony ILCE 1. You will find the seccond gain level where the curve raise at about ISO 500.

Thank you. I’ve seen that but what about the various video picture profiles? Do I simply apply the 2-1/3 stops rule?

Yes,

S-Cinetone, 125 and 640 (nearest)

Slog3, 800 and 4000

Thanks Charles!

 

[Entropy512]

I know with the A7Siii it is said the second native ISO kicks in 4-1/3 stops above the base ISO.

Does the 4-1/3 formula not apply to the A1? I’ve seen in a number of places that the second native ISO kicks in at 500 ISO for stills. So with the base ISO being 100, this comes out to be 2-1/3 stops. Does this same math apply to video? PP11 (S-Cinetone) has a base ISO of 125. Using the 2-1/3 stops formula would yield a second native ISO of 640.

Am I correct or am I missing something?

There isn't a rule. The point at which the second gain setting kicks in is determined by the designer, not by some general property of sensor design.

There are dual gain sensors with an base ISO of 100, where the second gain setting starts at 400, others at 600ish. The A1 is 500.

I don't know if you can apply a proportion to get the start of dual gain in S-Cinetone - someone else may know, or it may have to be measured.

For "alternative" picture profiles, take the ratio of the PP's minimum ISO to the camera's "normal" minimum ISO (NORMALLY the minimum is 100, the A7S3 is a notable exception where the "normal" minISO is either 64 or 80, I forget the exact number)

Then take the dualgain cutin ISO from Bill's charts and multiply it by that ratio.

This is USUALLY safe unless there is "extended ISO fakery" involved - for example in the case of S-Log3 at ISOs lower than 640 on the A7S3, the sensor is operating at the same gain configuration, and the sensor output is scaled downwards before applying the S-Log3 linear to log formula, so that the sensor clip point translates to a lower output code value than normal.

 

[DerrickRR]

I know with the A7Siii it is said the second native ISO kicks in 4-1/3 stops above the base ISO.

Does the 4-1/3 formula not apply to the A1? I’ve seen in a number of places that the second native ISO kicks in at 500 ISO for stills. So with the base ISO being 100, this comes out to be 2-1/3 stops. Does this same math apply to video? PP11 (S-Cinetone) has a base ISO of 125. Using the 2-1/3 stops formula would yield a second native ISO of 640.

Am I correct or am I missing something?

There isn't a rule. The point at which the second gain setting kicks in is determined by the designer, not by some general property of sensor design.

There are dual gain sensors with an base ISO of 100, where the second gain setting starts at 400, others at 600ish. The A1 is 500.

I don't know if you can apply a proportion to get the start of dual gain in S-Cinetone - someone else may know, or it may have to be measured.

For "alternative" picture profiles, take the ratio of the PP's minimum ISO to the camera's "normal" minimum ISO (NORMALLY the minimum is 100, the A7S3 is a notable exception where the "normal" minISO is either 64 or 80, I forget the exact number)

Then take the dualgain cutin ISO from Bill's charts and multiply it by that ratio.

This is USUALLY safe unless there is "extended ISO fakery" involved - for example in the case of S-Log3 at ISOs lower than 640 on the A7S3, the sensor is operating at the same gain configuration, and the sensor output is scaled downwards before applying the S-Log3 linear to log formula, so that the sensor clip point translates to a lower output code value than normal.

 

[AlephNull]

I know with the A7Siii it is said the second native ISO kicks in 4-1/3 stops above the base ISO.

Does the 4-1/3 formula not apply to the A1? I’ve seen in a number of places that the second native ISO kicks in at 500 ISO for stills. So with the base ISO being 100, this comes out to be 2-1/3 stops. Does this same math apply to video? PP11 (S-Cinetone) has a base ISO of 125. Using the 2-1/3 stops formula would yield a second native ISO of 640.

Am I correct or am I missing something?

There isn't a rule. The point at which the second gain setting kicks in is determined by the designer, not by some general property of sensor design.

There are dual gain sensors with an base ISO of 100, where the second gain setting starts at 400, others at 600ish. The A1 is 500.

I don't know if you can apply a proportion to get the start of dual gain in S-Cinetone - someone else may know, or it may have to be measured.

For "alternative" picture profiles, take the ratio of the PP's minimum ISO to the camera's "normal" minimum ISO (NORMALLY the minimum is 100, the A7S3 is a notable exception where the "normal" minISO is either 64 or 80, I forget the exact number)

Then take the dualgain cutin ISO from Bill's charts and multiply it by that ratio.

This is USUALLY safe unless there is "extended ISO fakery" involved - for example in the case of S-Log3 at ISOs lower than 640 on the A7S3, the sensor is operating at the same gain configuration, and the sensor output is scaled downwards before applying the S-Log3 linear to log formula, so that the sensor clip point translates to a lower output code value than normal.

A7S III minimum ISO is 80 according to the DPR overview.

 

[Entropy512]

I know with the A7Siii it is said the second native ISO kicks in 4-1/3 stops above the base ISO.

Does the 4-1/3 formula not apply to the A1? I’ve seen in a number of places that the second native ISO kicks in at 500 ISO for stills. So with the base ISO being 100, this comes out to be 2-1/3 stops. Does this same math apply to video? PP11 (S-Cinetone) has a base ISO of 125. Using the 2-1/3 stops formula would yield a second native ISO of 640.

Am I correct or am I missing something?

There isn't a rule. The point at which the second gain setting kicks in is determined by the designer, not by some general property of sensor design.

There are dual gain sensors with an base ISO of 100, where the second gain setting starts at 400, others at 600ish. The A1 is 500.

I don't know if you can apply a proportion to get the start of dual gain in S-Cinetone - someone else may know, or it may have to be measured.

For "alternative" picture profiles, take the ratio of the PP's minimum ISO to the camera's "normal" minimum ISO (NORMALLY the minimum is 100, the A7S3 is a notable exception where the "normal" minISO is either 64 or 80, I forget the exact number)

Then take the dualgain cutin ISO from Bill's charts and multiply it by that ratio.

This is USUALLY safe unless there is "extended ISO fakery" involved - for example in the case of S-Log3 at ISOs lower than 640 on the A7S3, the sensor is operating at the same gain configuration, and the sensor output is scaled downwards before applying the S-Log3 linear to log formula, so that the sensor clip point translates to a lower output code value than normal.

You lost me. Sorry.

Heh. Sadly it means - there is no easy answer because there are documented exceptions to every "general" rule of thumb out there.