Pushed ISO vs Native

[mediumformula]

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Hey.  I recently picked up a used M264 and was wondering what it means when the ISO is able to be pushed to 25000. From a technical standpoint what does this mean?  I am familiar with what pushing film is, but not sure how this terminology translates to digital sensors.  How is shooting at 25000 different than shooting at 12500 and then increasing the exposure one stop in Light Room?  For image quality, is it better to shoot at 12500 and increase exposure one stop in LR , or is it better to shoot at 25000 if really need that extra stop of light? 

When I have some time I intend to experiment with this a bit, but wanted to also get others' opinions.

Thanks

Edited March 2, 2020 by mediumformula

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[davidmknoble]

20 minutes ago, mediumformula said:

Hey.  I recently picked up a used M264 and was wondering what it means when the ISO is able to be pushed to 25000. From a technical standpoint what does this mean?  I am familiar with what pushing film is, but not sure how this terminology translates to digital sensors.  How is shooting at 25000 different than shooting at 12500 and then increasing the exposure one stop in Light Room?  For image quality, is it better to shoot at 12500 and increase exposure one stop in LR , or is it better to shoot at 25000 if really need that extra stop of light? 

When I have some time I intend to experiment with this a bit, but wanted to also get others' opinions.

Thanks

Congrats!  Pushed, generally, means the sensor isn't really tuned with the system for that ISO.  So, the results are much higher noise and frequently, some banding on the image.  Definitely experiment before relying on it.  I have found that at the extremely high ISO's exposing for the shadows helps.  You will blow some highlights, but then when you make it darker, some of the noise is reduced in the overall image.  Opening shadows in a high ISO image just makes it worse.... 

[mediumformula]

Thanks.  I'll try those tips. The technical reason for why it's called "PUSH" is still a bit murky to me.  Does anyone know what the camera is doing differently when it is raising ISO to 25000 as opposed to any lower number? 

[davidmknoble]

1 hour ago, mediumformula said:

Thanks.  I'll try those tips. The technical reason for why it's called "PUSH" is still a bit murky to me.  Does anyone know what the camera is doing differently when it is raising ISO to 25000 as opposed to any lower number? 

It is amplifying the light more.  Too much and he extra noise.  You could push it to iso 100,000 but the image would be unusable. Think of it as a questionable image level not up to Leica’s I age quality standards. 

[CVickery]

As I understand it the "native ISOs" are achieved by amplifying the data in hardware...like turning up the volume. "Push" settings on the other hand will underexpose the image and boost the exposure in the processing afterwards.

[a.noctilux]

Have a look here for dynamic range

versus ISO (link)

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[mediumformula]

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On 3/10/2020 at 3:05 PM, CVickery said:

As I understand it the "native ISOs" are achieved by amplifying the data in hardware...like turning up the volume. "Push" settings on the other hand will underexpose the image and boost the exposure in the processing afterwards.

Ok, so if the "Push" setting simply uses image processing to get the extended ISO, then would it be better to shoot in 12500 and increase expose by a stop in LR?  At this point aren't you just deciding whether to let the camera's software increase exposure vs. lightroom?  Is there a benefit to one or the other regarding image quality? 

[Good To Be Retired]

On 3/12/2020 at 12:22 PM, mediumformula said:

Ok, so if the "Push" setting simply uses image processing to get the extended ISO, then would it be better to shoot in 12500 and increase expose by a stop in LR?  At this point aren't you just deciding whether to let the camera's software increase exposure vs. lightroom?  Is there a benefit to one or the other regarding image quality? 

If this general subject is a topic of particular interest, you might enjoy Googling "ISO invariance".

Your immediate question would require rather a lot of verge to adequately  address>

Edited March 25, 2020 by Good To Be Retired

[a5m]

On 3/12/2020 at 12:22 PM, mediumformula said:

At this point aren't you just deciding whether to let the camera's software increase exposure vs. lightroom?  Is there a benefit to one or the other regarding image quality? 

Precisely.

From my understanding, it's better to use computer software over the camera's because of processing power. A computer simply has more of it therefore the software is more capable therefore better image quality pushing in post.