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by DChan on Mon Mar 04, 2019 9:29 pm
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According to Tony:

ISO is totally FAKE. Seriously.


And what Thom said:

Is ISO Fake?
 

by SantaFeJoe on Mon Mar 04, 2019 10:26 pm
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An old topic that gets lots of opinions, but still goes on with all the “experts”. Here’s a link to an article by Roger N. Clark from a long time ago:

http://www.clarkvision.com/articles/iso/

Joe
Learn the rules like a pro, so you can break them like an artist.  -Pablo Picasso
 

by E.J. Peiker on Tue Mar 05, 2019 8:57 am
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And a bit of a rebuke:
https://dslrbodies.com/cameras/camera-a ... -fake.html
 

by SantaFeJoe on Tue Mar 05, 2019 9:01 am
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E.J. Peiker wrote:And a bit of a rebuke:
https://dslrbodies.com/cameras/camera-a ... -fake.html
Part of DChans original post above.

Joe
Learn the rules like a pro, so you can break them like an artist.  -Pablo Picasso
 

by E.J. Peiker on Tue Mar 05, 2019 9:06 am
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More on this:
https://www.youtube.com/watch?v=EvJ-H_xl3zE
https://www.youtube.com/watch?time_cont ... Ab85TukSuc
 

by Mike in O on Tue Mar 05, 2019 1:57 pm
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Obviously, we have analog minds and have difficulty in a digital world with conversions. I tend to shoot unless on auto at 100 or 640...with dual gain I know I can push exposure in post to what looks best.
 

by SantaFeJoe on Thu Mar 28, 2019 8:17 pm
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Another article:

https://www.rawdigger.com/howtouse/iso- ... gital-gain

Check this out. It is a real eye opener about Fuji:

https://www.fastrawviewer.com/blog/fujifilm-x-series-iso-bracketing

Joe
Learn the rules like a pro, so you can break them like an artist.  -Pablo Picasso
 

by E.J. Peiker on Thu Mar 28, 2019 11:38 pm
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If the sensor is ISO invariant or largely ISO invariant, there is none to little difference whether the gain is applied in the output circuitry in the camera or via a boost in software. Most current Sony sensors are about as close to ISO invariant as you can get with just the auto gain at ISO 640 which makes 640 as clean or even slightly cleaner than 400. Canon sensors across the board are pretty far from ISO invariant so it makes a visible difference there.
 

by SantaFeJoe on Fri Mar 29, 2019 8:21 am
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So, if I’m understanding correctly, on many cameras it only wastes storage space on a memory card to bracket ISO. Is that correct? Then, it would be very important to know how your camera handles ISO bracketing.

Joe
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by E.J. Peiker on Fri Mar 29, 2019 9:16 am
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SantaFeJoe wrote:So, if I’m understanding correctly, on many cameras it only wastes storage space on a memory card to bracket ISO. Is that correct? Then, it would be very important to know how your camera handles ISO bracketing.

Joe
On Canon cameras no, on cameras with a Sony sensor, maybe, depends on the sensor and whether or not you are going over ISO 640 in the bracket.  You can see what I mean below - on most Sony sensors there is hardware gain applied at ISO 640.  So if your bracket is ISO 100/200/400 then you can just shoot it at 100 and add 1 stop and 2 stops in post.  But if your bracket goes to 800 then there is a difference.
Image
 

by E.J. Peiker on Fri Mar 29, 2019 10:04 am
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Here is another related graph for newer Sony cameras and many cameras made with Sony sensors.  As I've been saying here and in other places for a couple of years at least, if you need to go much over ISO 250, you might as well go to 640.  Shot noise is a factor too which pushes it out to about ISO 320.  The point though is that you are getting poorer image quality at ISO 400 and 500 than you are at ISO 640.  I recommend anybody shooting wildlife/birds, or any other situation where you might want to raise the ISO, to put a Sony a73, a7R3, a9 to ISO 640, not ISO 400...
Image
 

by Gene Gwin on Mon Apr 08, 2019 12:21 pm
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E.J., Thanks for providing this information. Guess I should have listening better. Question: Does this graph also apply to the D850 since the sensor was designed by Nikon, but built by Sony? Also, would this graph apply to the Nikon D7500? Thanks.....
 

by E.J. Peiker on Mon Apr 08, 2019 3:02 pm
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Gene Gwin wrote:E.J., Thanks for providing this information. Guess I should have listening better.  Question:  Does this graph also apply to the D850 since the sensor was designed by Nikon, but built by Sony?  Also, would this graph apply to the Nikon D7500?  Thanks.....
No, Nikon chose a different point to apply the second level of hardware gain, this is not done on sensor, it is done in the next stage, Basically ISO 250 and 320 are useless on a D850 - might as well go to 400.
Image
 

by Gene Gwin on Mon Apr 08, 2019 9:40 pm
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E.J., Thanks.....
 

by Todd Bauer on Sun May 12, 2019 11:55 am
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E.J. Peiker wrote:
Gene Gwin wrote:E.J., Thanks for providing this information. Guess I should have listening better.  Question:  Does this graph also apply to the D850 since the sensor was designed by Nikon, but built by Sony?  Also, would this graph apply to the Nikon D7500?  Thanks.....
No, Nikon chose a different point to apply the second level of hardware gain, this is not done on sensor, it is done in the next stage, Basically ISO 250 and 320 are useless on a D850 - might as well go to 400.
Image
Interesting. I read a long time ago that with Nikon, you should shoot in increments of 160 (320/640), and with Canon 200 (400/800). Noticed that a lot of Nikon pros (albeit not necessarily D850) tended to stick to it. You're far more informed that myself. That's inaccurate?
Todd Bauer
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by E.J. Peiker on Sun May 12, 2019 12:16 pm
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Todd, the graph above shows that you can go in 1/3 stops on ISO but if you are at 200, there's essentially no point in going to 250 or 320 - just go straight to 400. On a Sony, it's pointless to go to 400 or 500 if you need to go past 320, just go to 640. The info that you have is very old and from many generations of sensors ago, way before the advent of dual gain output stages.
 

by Todd Bauer on Sun May 12, 2019 12:24 pm
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E.J. Peiker wrote:Todd, the graph above shows that you can go in 1/3 stops on ISO but if you are at 200, there's essentially no point in going to 250 or 320 - just go straight to 400.  On a Sony, it's pointless to go to 400 or 500 if you need to go past 320, just go to 640.  The info that you have is very old and from many generations of sensors ago, way before the advent of dual gain output stages.
Thanks for your time. Very informative.
Todd Bauer
Houston, TX
 

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