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I2 X5S: New firmware ISO lock issue...
1731 11 2017-4-9
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Conrad Jay
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I have the I2 X5S with prores/cdng software keys. Lens: DJI 15mm, Olympus M.Zuiko 25mm, Olympus M.Zuiko 45mm
Im having trouble after the most recent early 2017 firmware update when shooting d-log. I cannot adjust my iso anymore? I know it was said the minimum iso was now going to be 500 (which is lame and a rant in its self base on retained dynamic range...) However that is the change that has been made and will have to live with it... But the problem is I cant even move the iso slider at all? When I do it pops back to 6400iso which is stupid high... unsuable in most cases.  

Any thoughts or insights? Am I missing something?

Thanks

Conrad
2017-4-9
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Barry Goyette
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you're missing something. :-) The ISO in D-Log is locked to 500.  Many manufacturers do something akin to this (while they may allow you to adjust ISO, it's largely the same effect as pushing or pulling the file in post, as the available DR is only what the sensor is capable of.) By locking it at 500, DJI is attempting to give you the best compromise between DR and noise. If you want to shoot at ISO 100, then open up 2.3 stops, you will have less noise in your shadows, but lose some range in the highlights. If you want to shoot at ISO 2000, underexpose by 2 stops, you will have noisier crushed shadows, but more range in the highlights. If you do in RAW or ProRes, there will be little to no difference between this method and DJI letting you adjust in camera (they will probably bring this back according to Mr. CAO from engineering). Shooting H264 may see some differences between gaining in post versus camera, but there's no way to tell at this point.
FWIW, the new D-log is a huge improvement over the old D-log, even when locked at 500. Give it a shot.

2017-4-9
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JBSonic
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Which software do you use with your cinema dng raw files ?
2017-4-10
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Mike-the-cat
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Barry Goyette Posted at 2017-4-9 15:33
you're missing something. :-) The ISO in D-Log is locked to 500.  Many manufacturers do something akin to this (while they may allow you to adjust ISO, it's largely the same effect as pushing or pulling the file in post, as the available DR is only what the sensor is capable of.) By locking it at 500, DJI is attempting to give you the best compromise between DR and noise. If you want to shoot at ISO 100, then open up 2.3 stops, you will have less noise in your shadows, but lose some range in the highlights. If you want to shoot at ISO 2000, underexpose by 1.6 stops, you will have noisier crushed shadows, but more range in the highlights. If you do in RAW or ProRes, there will be little to no difference between this method and DJI letting you adjust in camera (they will probably bring this back according to Mr. CAO from engineering). Shooting H264 may see some differences between gaining in post versus camera, but there's no way to tell at this point.
FWIW, the new D-log is a huge improvement over the old D-log, even when locked at 500. Give it a shot.

Thanks. Informative reply!
2017-4-10
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Conrad Jay
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Barry Goyette Posted at 2017-4-9 15:33
you're missing something. :-) The ISO in D-Log is locked to 500.  Many manufacturers do something akin to this (while they may allow you to adjust ISO, it's largely the same effect as pushing or pulling the file in post, as the available DR is only what the sensor is capable of.) By locking it at 500, DJI is attempting to give you the best compromise between DR and noise. If you want to shoot at ISO 100, then open up 2.3 stops, you will have less noise in your shadows, but lose some range in the highlights. If you want to shoot at ISO 2000, underexpose by 2 stops, you will have noisier crushed shadows, but more range in the highlights. If you do in RAW or ProRes, there will be little to no difference between this method and DJI letting you adjust in camera (they will probably bring this back according to Mr. CAO from engineering). Shooting H264 may see some differences between gaining in post versus camera, but there's no way to tell at this point.
FWIW, the new D-log is a huge improvement over the old D-log, even when locked at 500. Give it a shot.

Interesting. Thanks for the info!

Yeah... sorta knew about the 500 iso lock... but the DR is degraded at this point... no? It says right on the website... If its locked into 500iso, then the dynamic range would only be about 10 to 11 stops rather than the full 12.8stops... Thats my biggest concern... Again, that simply base on the info from there website... Higher the iso, worse the DR.

When sooting RED, or other cameras yeah... so called having the sensor at its native iso is best... But that information on  DJI website is conflicting...

Like to here your thoughts.

Scroll down to the Dynamic range / iso section
https://www.dji.com/zenmuse-x5s
2017-4-14
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raven4
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There's absolutely no difference between Standard RAW and DLOG RAW except that the ISO is locked and there's a flag in the metadata for your NLE to use ISO500 in debayering the RAW.Knowing this, you can feel free to select whatever format of RAW you want. Just be sure to manually compensate in your NLE. Please note that none of what I just wrote is true for DLOG ProRes. That's an entirely different treatment than in RAW. In order to see the highest DR available, in Davinci Resolve, set your RAW fields to 709/Linear. Then, use the bundled VFXIO LUTS to conver the linear data to whatever format of REC709 you want.
Considering that REC709 has a dynamic range of 7 stops, for most SDR applications, you'll never notice that loss  by locking the ISO to 500. But, if you need to use the full 12.5 stops, for some reason like delivering to REC2020, perhaps shooting at STandard RAW is in order.
2017-4-14
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Barry Goyette
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Conrad Jay Posted at 2017-4-14 10:43
Interesting. Thanks for the info!

Yeah... sorta knew about the 500 iso lock... but the DR is degraded at this point... no? It says right on the website... If its locked into 500iso, then the dynamic range would only be about 10 to 11 stops rather than the full 12.8stops... Thats my biggest concern... Again, that simply base on the info from there website... Higher the iso, worse the DR.

yeah..no. Not quite how it works. Native ISO is the "true" ISO of the camera based on where middle grey falls (this isn't an exact thing, and manufacturers play around with "where" 18% grey falls.)

BASE ISO in a camera that shoots LOG is generally 2 or more stops faster than native ISO, and is set by the manufacturer as a compromise between dynamic range and noise. All sensors have a saturation point...a maximum highlight value that cannot be exceeded, but the number of stops that exist below middle grey, in the shadows, is much more squishy, and is usually "set" by the manufacturer based on a certain standard for noise (this is why there can often be a bit of controversy as to the actual DR of a camera). When you look at a xyla chart, you will often see several steps below what the stated shadow "range" is, but those steps are too noisy to be useful.

By setting the ISO at 500, DJI is essentially asking you to give the camera less exposure than it's native ISO of 100, which means it will accept a greater range in the highlights, and at the same time show an acceptable level of noise in the shadows, and this is the point where the sensor achieves "maximum" dynamic range. (it achieves this by applying some gain to the image, and that gain is what's truly responsible for extending the DR. At ISO 100, no gain is applied and thus the DR is less.) Rating the sensor any higher will simply push the shadows down deeper into the noise and not increase DR in a meaningful way. All true logs work this way, and you'll find that Arri, Canon, Sony and probably RED, all have a Base ISO that is several stops faster than their true, native ISO, for use in log gammas.

DJI isn't doing anything novel here other than "locking" the ISO (sony does this too, but offers some workarounds). Canon allows you to adjust ISO, but clamps the highlights for ISOs below base, effectively lowering the possible dynamic range. Arri does something similar.
2017-4-14
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Mike-the-cat
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Barry Goyette Posted at 2017-4-14 11:28
yeah..no. Not quite how it works. Native ISO is the "true" ISO of the camera based on where middle grey falls (this isn't an exact thing, and manufacturers play around with "where" 18% grey falls.)

BASE ISO in a camera that shoots LOG is generally 2 or more stops faster than native ISO, and is set by the manufacturer as a compromise between dynamic range and noise. All sensors have a saturation point...a maximum highlight value that cannot be exceeded, but the number of stops that exist below middle grey, in the shadows, is much more squishy, and is usually "set" by the manufacturer based on a certain standard for noise (this is why there can often be a bit of controversy as to the actual DR of a camera). When you look at a xyla chart, you will often see several steps below what the stated shadow "range" is, but those steps are too noisy to be useful.

Thanks Barry. Glad we have you posting on this forum
2017-4-15
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raven4
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Mike-the-cat Posted at 2017-4-15 08:08
Thanks Barry. Glad we have you posting on this forum

In the case of LOG, not sure what all the bruhaha is about. If you don't like being locked to 500ISO, open or close the aperture 2.3 stops. SOS.
2017-4-15
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Mike-the-cat
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raven4 Posted at 2017-4-15 09:59
In the case of LOG, not sure what all the bruhaha is about. If you don't like being locked to 500ISO, open or close the aperture 2.3 stops. SOS.

Barry,  I don't even use D-LOG, if I need wide DR, I go to RAW. So its other folks who are obsessed about this , not me.
2017-4-15
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Barry Goyette
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Mike-the-cat Posted at 2017-4-15 21:25
Barry,  I don't even use D-LOG, if I need wide DR, I go to RAW. So its other folks who are obsessed about this , not me.

Not that it matters much...but that was Raven4, not me. :-)
2017-4-17
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Mike-the-cat
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Barry Goyette Posted at 2017-4-17 12:15
Not that it matters much...but that was Raven4, not me. :-)

oops! Sorry Barry. Cross-eyed me...
2017-4-17
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