ASA Clarification

[Jeremy Neish]

After doing a film out test, we think we have determined that it's best not to adjust the ASA away from ASA 320 if at all possible. Because as I understand it, adjusting the ASA doesn't actually change anything about what is being recorded to RAW. It's only changing what I'm seeing on the screen and the associated metadata.

The problem becomes if you set the ASA below 320, you start to overcompensate for the dimmness of what is being seen in the display and you end up overexposing your highlights. Conversely, if you set the ASA too high you end up overcompensating for the brightness of the display and end up underexposed.

This is all based on my limited understanding of how Red RAW and the ASA interact. Please, please, please correct me if I'm wrong.

Yes, I realize keeping an eye on the various meters can help, but your instincts are to compensate for what is being seen visually on the display.

 

[David Mullen ASC]

You have to be flexible when applying film notions like ASA to a digital camera. 320 ASA may not be optimal, noise-wise or detail-wise, for all subjects depending on their dynamic range and how the image will be color-corrected in post. It is only a starting point for thinking about lighting and exposure.

 

[Jeremy Neish]

Okay, that helps.

I'm still a bit fuzzy about the technical specifics about Red RAW and ASA. I've read several times that the ASA is really just metadata and not "destructive" in any way. Is that true? If that's the case it seems to me, that the dangers I mentioned above are valid.

We especially noticed that anytime we shot ASA 100 or 200, we ended up inadvertantely blowing out some highlights. But were much less inclined to at 320. However, on a night shot, I can see it being very difficult to see what you are shooting if you have the camera set at ASA 320.

Thanks for your clarifications.

By the way, our film-out test looked fantastic. And it was just an 8-bit ProRes 422 film out. We didn't have time to do a proper conform. I was particularly surprised how unnoticable the noise was at "ASA 2000" once it was intermixed with the film grain. I could barely tell the difference between 800 and 2000.

 

[Owal Tec]

Also, on a related note, is there a baseline/default temperature of the Red Sensor? Tungsten? Daylight?

 

[Evin Grant]

Seems like daylight, but it matters little.

 

[REDBLUE&GREEN]

JEREMYN: Surprized to hear that you are getting highlights blow out at 100 or 200. The Camera captures Raw.... so you should be able to shoot plus or minus at least 3 1/2 or 4 stops without blowing out. Can someone explain this?

Also I went to HDexpo in Burbank, CA last week and saw some red footage at the ProMax booth. They were projecting on a 1080p projector. The daylight footage/ or with a lot of light looked great. But the low light or night footage looked....not very good at all.

Can someone explain....Is the Red less than good in low light???? Was Promax just showing footage that was not great??? Who can explain this?

Also if Red is a daylight sensor...don't you have to color correct... ... Red has nd's and 85 built in........ right???

Thanks......

 

[Evin Grant]

JEREMYN: Surprized to hear that you are getting highlights blow out at 100 or 200. The Camera captures Raw.... so you should be able to shoot plus or minus at least 3 1/2 or 4 stops without blowing out. Can someone explain this?

RBG, I don't know what camera you are used to using but no DSLR or other RAW camera I've ever heard of can handle more than 1-1.5 stops over exposure (Clipping/Blow out) and hold highlight detail.

Also I went to HDexpo in Burbank, CA last week and saw some red footage at the ProMax booth. They were projecting on a 1080p projector. The daylight footage/ or with a lot of light looked great. But the low light or night footage looked....not very good at all.

Can someone explain....Is the Red less than good in low light???? Was Promax just showing footage that was not great??? Who can explain this?

This was our footage (The Redninas) and indeed some of the shadow noise you were seeing was from the projector becasue in order to fight the light pollution from the show floor we had to boost it's brightness and gamma. Also bear in mind the nightime footage (choppers and music vid.) were shot at ISO 640, one stop under exposed. This was an aesthetic choice and adds a bit of low end noise but does so in a very organic way IMHO. As far as it being "not great" I disagree, and quite a few who stopped by the booth that day remarked about how much better it was than other cameras in low light.
But if you really need a noiseless/grainless image you could always shoot at T1.3 and ISO 320 and you'd be fine.

Also if Red is a daylight sensor...don't you have to color correct... ... Red has nd's and 85 built in........ right???

Thanks......

Red has no built in filtration, and no you do not need to filter it becasue the color information is recorded in the RAW format and can be set later. You would not be able to discern any difference from shooting with an 85 or without.

 

[Sanjin Jukic]

"...RED ONE has ASA and white balance settings on the camera body that really control nothing more than the display output and are totally nondestructive to the RAW image.

Basically, the iris and shutter speed, or any filters you shoot through, are the only things impacting how the image is exposed, and you will not truly see what you’ve got, and what information is available to you, until you download the material from the camera and run it through the RED Alert software on your Mac (Note: REDCINE will be available for both the Mac and PC).

REVIEW: RED ONE Digital Cinema Camera
by James Mathers

 

[LighthouseMEdia]

I think I understand Jeremy to say he is changing the ASA and then setting the exposure by eye or the monitor. If you change the ASA then I would change the ASA on a light meter and use that to set your exposure and trust it above your monitor!

 

[Joel Kaye]

I think I understand Jeremy to say he is changing the ASA and then setting the exposure by eye or the monitor. If you change the ASA then I would change the ASA on a light meter and use that to set your exposure and trust it above your monitor!

Yeah that's right. This has come up before and from everything I'm reading it sure looks like you should be rating the camera at 320 or maybe even 400/500 for safety. You're in more danger of blowing out highlights than you are of losing detail in the shadows...

From scene to scene you're going to have to evaluate what parts of the scene should receive the rated exposure and let everything else fall where it may. Relight it if that's causing big problems. You've only got 11ish stops to work with... spend them wisely.

As always testing through output will show the way. The original poster learned a lot by doing that.