Native ISO help A1/A7RV/A7R1V

[cameraaddict]

Hey everyone, I'm trying to confirm native ISOs for photos, S Log 3, and S Cinetone for the A1, A7RV and A7RIV. Sony doesn't officially publish the information so I reached out to Sony Pro Support who said that they couldn't share that data. Interestingly, they share it for their cineline cameras but not the Alphas. The rep from Sony Pro, who was very helpful yet apologetic, also said that no manufacturers actually share that data. Below is a list of what I found after trolling around online. and asking ChatGPT for answers. If anyone can definitively confirm, deny or correct the information it would be greatly appreciated. Thanks!

Sony Alpha 1

1. Photos (RAW/JPEG)

• Native ISO: The A1’s base ISO for still photography is ISO 100, which is its cleanest setting for high dynamic range.
• Optimal Range: ISO 100-500 is where you'll see the best image quality.

2. S-Log3 (Video)

• Base ISO: For S-Log3, Sony recommends shooting at ISO 800 as the base ISO for optimal dynamic range.
• Dual ISO-Like Behavior: Although not officially dual native, the camera performs well at ISO 3200 and above,
• Optimal Range: ISO 800 and ISO 3200 are considered the sweet spots for dynamic range in S-Log3.

3. S-Cinetone (Video)

• Base ISO: S-Cinetone is optimized for a base ISO of ISO 100 in the Alpha 1.
• Optimal Range: For the best image quality in S-Cinetone, stick to ISO 100-800. You’ll retain good color fidelity and dynamic range within this range

Sony A7RV
1. Photos (RAW/JPEG)

• Native ISO: The base ISO for stills on the A7R V is ISO 100, which provides the cleanest image with the highest dynamic range

2. S-Log3 (Video)

• Base ISO: The A7R V has a base ISO of 640 for S-Log3, which is its lowest native ISO setting for this profile.
• Dual ISO-Like Performance: While not officially “dual native,” the A7R V has a second, higher ISO sweet spot at ISO 3200 for S-Log3. This is where the camera produces cleaner shadows and better noise handling in low light, making it feel like a second native ISO.
• Optimal Range: ISO 640 and ISO 3200 are the best for dynamic range in S-Log3, with ISO 3200 offering good results for low-light shooting.

3. S-Cinetone (Video)

• Base ISO: The base ISO for S-Cinetone on the A7R V is ISO 125.
• Optimal Range: ISO 125-800 in S-Cinetone gives you the best color and dynamic range.

SonyA7RIV
1. Photos (RAW/JPEG)

• Native ISO: The A7R IV's base ISO for still photography is ISO 100
• Optimal Range: ISO 100-400 is ideal for maintaining high image quality with minimal noise. The camera’s high-resolution sensor does well in low light but introduces noise at higher ISOs, especially past ISO 800.

2. S-Log3 (Video)

• Base ISO: For S-Log3, the A7R IV’s base ISO is ISO 640, designed to maximize dynamic range while controlling noise.
• Dual ISO-Like Behavior: While the A7R IV doesn’t have a second native ISO for S-Log3, ISO 2000 and above tend to perform better in low light, offering cleaner shadows and reduced noise in S-Log3. This makes ISO 640 and ISO 2000 practical choices, similar to dual native ISOs

3. S-Cinetone (Video)

• Base ISO: S-Cinetone on the A7R IV is optimized for ISO 125 as its base.
• Optimal Range: ISO 125-800 offers the best image quality for S-Cinetone

 

[AlphaWorld]

All of these cameras have two "base" ISOs - the low base ISO is easy to find - it's the lowest ISO quoted by Sony as not "extended". The second gain ISO isn't published by Sony, but it's where a different gain is applied to the sensor. Easiest way to discover the second gain ISO is to visit the fantastic public service that is Photons2Photos: https://www.photonstophotos.net/

Here's the Dynamic Range vs ISO chart: https://www.photonstophotos.net/Charts/PDR.htm

Circles are "extended" ISOs. Filled dots are real ISOs. First base ISO is 100 (no surprise). The second gain ISO for the A1 is 500 - you get better dynamic range shooting at ISO 500 than at 400 or even 320.

You can put multiple cameras on the chart to compare them.

A7RV second gain ISO is ISO 320. Same for the A7RIV (same sensor).

For contrast, the A9 III second gain kicks in at ISO 800.

Knowing the second gain point is useful is you shoot in conditions requiring a mid-range ISO.

Dual gain sensors are used in pretty much all modern stills cameras.

Dual gain also applies in video - I think the A1, for example, has base of 800 in log shooting, with 3200 as the second gain step. I don't know where to go to get the most authoritative answer for video.

 

[cameraaddict]

All of these cameras have two "base" ISOs - the low base ISO is easy to find - it's the lowest ISO quoted by Sony as not "extended". The second gain ISO isn't published by Sony, but it's where a different gain is applied to the sensor. Easiest way to discover the second gain ISO is to visit the fantastic public service that is Photons2Photos: https://www.photonstophotos.net/

Here's the Dynamic Range vs ISO chart: https://www.photonstophotos.net/Charts/PDR.htm

Circles are "extended" ISOs. Filled dots are real ISOs. First base ISO is 100 (no surprise). The second gain ISO for the A1 is 500 - you get better dynamic range shooting at ISO 500 than at 400 or even 320.

You can put multiple cameras on the chart to compare them.

A7RV second gain ISO is ISO 320. Same for the A7RIV (same sensor).

For contrast, the A9 III second gain kicks in at ISO 800.

Knowing the second gain point is useful is you shoot in conditions requiring a mid-range ISO.

Dual gain sensors are used in pretty much all modern stills cameras.

Dual gain also applies in video - I think the A1, for example, has base of 800 in log shooting, with 3200 as the second gain step. I don't know where to go to get the most authoritative answer for video.

Thanks AlphaWorld! Now if only I could find those pesky video ISOs. I don't know why they don't share the info in the first place- it would only help their users produce better images/videos and presumably help sell more cameras.

 

[Richard A]

A7RV second gain ISO is ISO 320. Same for the A7RIV (same sensor).

That is correct.

For S-Log3 on the A7R V the ISO's are 800 and 2500. For S-Cinetone they are 125 and 400.

An easy way to remember this, for the A7RV, is that the ‘Gain’ ISO is 5/3 stops higher than the Base ISO.

 

[cameraaddict]

That is correct.

For S-Log3 on the A7R V the ISO's are 800 and 2500. For S-Cinetone they are 125 and 400.

An easy way to remember this, for the A7RV, is that the ‘Gain’ ISO is 5/3 stops higher than the Base ISO.

Thanks Richard! This is super helpful!