How much grain structure should there be in the Helium - Epic W?

[Brendan H. Banks]

If you know if you were on the new or the old calibration, it could be really, really easy to figure out what is happening here...or it could just help your further conversations with Graeme.

If you are on the beta firmware and did NOT go to Menu>Image>ISO and UNCHECK Use new ISO calibration for Helium sensor, you were not following the suggestion that Graeme made. He made the 1280ISO suggestion as a starting point to experiment for people who just received the Epic-W shortly after it came out. What happened in the new beta is a change in sensor calibration which means that what used to be 1280, is now 640. So going by that, if you were on the new beta and did not uncheck the new ISO Calibration, you were using an ISO equivalent to 2500. I would put my money on that being where the noise is coming from.

I would suggest taking a look at this document - http://s3.amazonaws.com/red_3/downloads/other/white-papers/ISO Recalibration for HELIUM.pdf

 

[Michael Hoffman]

Oh, man - I must have missed that.

That probably explains it all.

Geeze. Crap. LOL.

No wonder the dynamic range is somewhat limited - I did everything BUT that - I will see if that's unchecked... but odds are - it isn't.

No doubt - this will be a bit grainy.

- Mike

 

[Mike Finegan]

If you know if you were on the new or the old calibration, it could be really, really easy to figure out what is happening here...or it could just help your further conversations with Graeme.

If you are on the beta firmware and did NOT go to Menu>Image>ISO and UNCHECK Use new ISO calibration for Helium sensor, you were not following the suggestion that Graeme made. He made the 1280ISO suggestion as a starting point to experiment for people who just received the Epic-W shortly after it came out. What happened in the new beta is a change in sensor calibration which means that what used to be 1280, is now 640. So going by that, if you were on the new beta and did not uncheck the new ISO Calibration, you were using an ISO equivalent to 2500. I would put my money on that being where the noise is coming from.

I would suggest taking a look at this document - http://s3.amazonaws.com/red_3/downloads/other/white-papers/ISO Recalibration for HELIUM.pdf

In the referenced doc - it says helium will now match metter readings but will need to be adjusted one stop to match iso on other red cameras. So helium now matches meter readings but all other red are off by one stop compared to meter readings? iso800 is still the factory recommendation for sweet spot, even though that is equivalent to iso1600 on other red sensors? If I liked iso1000 on original EpicW Helium (pre IPP2) - then I would actually target iso400-500 now? If I am shooting Raven and EpicW Helium they should be one stop different - so 400 on Helium for 800 on Raven?
Might be helpful to see a brief tech note showing IPP2 settings for two camera shoot where one is Helium and one is not.

 

[Michael Hoffman]

Just checked.

You are correct. Not unchecked. Ugggggh.

Some of this stuff - after grade - looks GREAT too. But the noise in the blue and blacks is killer.

It does have a film-like grain appearance - so I'll have to DNR the 4K Pro Res files when I'm done with the grade (this Dual D700 Mac Pro dies upon attempting to denoise the 8K RAW files).

Extra steps. I appreciate your input - and will message Graeme too. 10 bucks says - this is why my whites seemed to clip so fast too. Basically - I was just boosting the signal - like flipping the damn gain on my old Varicam - forcing me to stop down while gained up - to safe mode.

UGGGGH.

- Mike

 

[Michael Hoffman]

Mike - I agree with you there.

The language in that document is a bit confusing for me as well.

 

[Brendan H. Banks]

In the referenced doc - it says helium will now match metter readings but will need to be adjusted one stop to match iso on other red cameras. So helium now matches meter readings but all other red are off by one stop compared to meter readings? iso800 is still the factory recommendation for sweet spot, even though that is equivalent to iso1600 on other red sensors? If I liked iso1000 on original EpicW Helium (pre IPP2) - then I would actually target iso400-500 now? If I am shooting Raven and EpicW Helium they should be one stop different - so 400 on Helium for 800 on Raven?
Might be helpful to see a brief tech note showing IPP2 settings for two camera shoot where one is Helium and one is not.

You actually nailed it with all of these. You are correct.

WHEN SHOOTING HELIUM + DRAGON IN NEW IPP2 BETA - Helium will be 1/2 the ISO to produce the same brightness of your DRAGON setup.

WHEN SHOOTING HELIUM + NON-RED - These should now be much closer to matching, if not matching dead-on.

If you decided to UNCHECK that box, then you will have the exact same values for matching Dragon cams.

Overall this is a move to have the RED system fit into a more universally accepted standard which is a good thing. Unfortunately some of the issues Michael has run into are the side effect.