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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

Opinion POLL: EPIC native ISO = 800 or ISO = 320?

Opinion POLL: EPIC native ISO = 800 or ISO = 320?

  • Total voters
    159
IMO it's 320 chip as evidenced by the RAW. But 800 ASA helps make up for the chip's biggest deficiency - highlight latitude at the expense of some extra noise. To act like the there is no native is like saying the chip has no specs. Raw looks like 320 and clips like hell if you expose to your eye.
 
Glad to get you back in the sandbox. :)

Ian Laurie said:
So is that what the ISO 800 recommendation is? just another way of ETTR? If thats the case, Thanks for clearing it up! I was always curious why the ISO800 MX was showing approx 320 in raw view. Who would have guessed that my trip on here to day would make me want to go play again.
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Karl,

That was exactly my situation. High contrast, bright whites and the dark side of the rock danced... with compression artifacts. That is really good to know. I'll upload my shot and let you judge yourself, then at least I can stop blaming it on noise.

Thanks Karl.

Karl H said:
yup that's exactly what I'm saying. However let my clarify and say it 'could' be noise. In dominiks case it look distinctly like compression artifacts to me, but I can't see your shot so who knows..... Check my 5K image from the original thread I linked to : http://www.darklineonline.co.uk/uploads/5k120test.jpg .This is not noise, the entire image is full of artifacts due to such a high contrast shot and also high compression. This isn't even 2K, but 5K.

Compression works best on midtones and highlights. To put it bluntly stuff in the shadows get the dregs of the compression bandwidth. I see it all the time on a lot of people's slo-mo footage. It's the shadows that dance. So if you're getting this then there's several options. Evin suggested a low con filter which sounds like it would help to lift those blacks. More light would also help (tho clipping would suffer). Buy a 512GB card and lower the compression ratio (not for me just yet!).

You learn to follow a few rules - for example a shot with lots of detail and high contrast @ high fps seems to be a nightmare for redcode. One with a shallow DOF and less details will probably be fine. Rating at 320 helps.
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That's great for those of us that own the camera and have the time. Test, test test. A lack of clarity on basic principals is bad for rental clients, DPs, potential owners, film makers, pretty much bad for RED in all ways. It's important to have guidelines to reference.

I was onset with a DP last month, promising young DP. She was sure the Epic's native ISO was 800. Was shooting at night, rating for 800 ISO. She loves the Alexia. How will she fall in love with the Epic if she doesn't know how to set the ISO/exposure?

I am so glad I posted this Poll, we need the conversation and I have learned so much. Thanks for contributing everyone.

Yousuf Abbasi said:
All I know is: with digital, it is pretty difficult to get good shadow detail, that's the biggest drawback of digital vs film. So, the way I compensate for that is effectively crank up all my highlights without clipping, this forces details to emerge from the shadows, then slide back to ISO320 in RCX for a well balanced shot that can compete with film (somewhat). So, in a sense, I am shooting in ISO800 but exposing for ISO320 (via over-exposing without clipping). Does that mean "native" is 320 or 800? I don't know.

If you have a methodology that works, then really its not that confusing. Just spend time with the camera, do trials and errors, and figure out what works. It's a tool, RED has designed it and gave us more options to work with, now it's up to me to learn it and find my "way" with it.
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OK, I'm straight up calling bullshit on all the noise about ISO 800 noise, and here's the pudding...

I just finished a music video for a local LA metal band and we shot a buch of post apocalyptic scenarios yada yada as well as a pretty cool samurai sword fight scene in the desert.
I shot this scene on my Epic lit by a few camp fires and a few tungsten units on a flicker box with full CTO none the less. On top of that I was shooting 4kHD and 8:1 compression.... @96FPS!

here is a 1080P frame grab out of RCX showing not only the frame as I shot it (very warm and fire-lit) but also corrected back to 2300K so you can see that the noise is far from an issue even with the channels way out of balance...
ISOtest1080.jpg


And for those that will inevitably say the 1080 is hiding more noise, here is the full 4KHD frame (I just didin't want to overwhelm the thread with a 4K image)
http://www.evingrant.com/pics/ISOtest.jpg

This is not a "noise free" image, but it's cleaner than any 500 ISO film stock I've ever shot, and I personally think it's quite subtle and organic in a way that adds to the cinematic quality of the Epic image.

Lenses were "B" super speeds at T2 and shutter was set at 240º since we planned on ramping back to 24 and 48 FPS.

If you can honestly look at these images and say "Wow that's too noisy for me man" especially given the conditions it was shot under, then no one here is going to be able to offer you an answer.
 
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Evin Grant said:
OK, I'm straight up calling bullshit on all the noise about ISO 800 noise, and here's the pudding...

I just finished a music video for a local LA metal band and we shot a buch of post apocalyptic scenarios yada yada as well as a pretty cool samurai sword fight scene in the desert.
I shot this scene on my Epic lit by a few camp fires and a few tungsten units on a flicker box with full CTO none the less. On top of that I was shooting 4kHD and 8:1 compression.... @96FPS!

here is a 1080P frame grab out of RCX showing not only the frame as I shot it (very warm and fire-lit) but also corrected back to 2300K so you can see that the noise is far from an issue even with the channels way out of balance...
ISOtest1080.jpg


And for those that will inevitably say the 1080 is hiding more noise, here is the full 4KHD frame (I just didin't want to overwhelm the thread with a 4K image)
http://www.evingrant.com/pics/ISOtest.jpg

This is not a "noise free" image, but it's cleaner than any 500 ISO film stock I've ever shot, and I personally think it's quite subtle and organic in a way that adds to the cinematic quality of the Epic image.

Lenses were "B" super speeds at T2 and shutter was set at 240º since we planned on ramping back to 24 and 48 FPS.

If you can honestly look at these images and say "Wow that's too noisy for me man" especially given the conditions it was shot under, then no one here is going to be able to offer you an answer.
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well if you had exposed at 1600 ISO, you would probably have had more light to get the sot in focus, LOL. Its a joke obviously its a motion shot in a rock music vid.
Nice shot by the way, I dig the original warm frame, better than the 2300K shot. Just my taste. firey must look firey
 
Evin, the stills looked really good until I clicked the 4K version. The 2300K brings out that noisy blue channel in the shadows which I hate. Not your fault, I think you did a pretty good job keeping it down. Just wish digital blue channels were better.

Sometimes I just want to put a CTB blue on everything and just carry extra lights to compensate for the lost stop. I know it's not practical, though. Especially in the setting you were in (night time lit only by a fire). I'm guessing you were wide open at T1.4.

But given everything, yes I agree with you, it's not that bad.
 
On the Epic, although I tend to set my ISO to 320 for everything, I use the RAW exposure tools (especially the false colour exposure one) the camera provides to ensure the picture areas I consider important are not highlight clipping or in the noise floor. That way my exposure will always be "good". Ie, the picture is to my liking AND I'm neither clipping or noisy where I don't want to be.

It really doesn't matter what the ISO is set at, if the exposure is wrong. I set ISO at 320 to match my Redcolor 3 view to match the RAW view exposure wise, as I like to be as WYSIWYG as possible, but I may adjust ISO higher if I want to have a brighter display for focusing in low light or if I really don't want to do much post adjustment. But otherwise, I don't consider the ISO setting to be that important.
 
Sending an ISO 320 image to video village has not worked out well for me on a number of occasions. YMMV. Obviously you can put a Davio in line or tweak the monitor, etc but just using 800 for the monitoring path and sneaking a peak at the gamma encoded RAW view works a charm. Just sayin'

Cheers - #19
 
Yousuf Abbasi said:
Evin, the stills looked really good until I clicked the 4K version. The 2300K brings out that noisy blue channel in the shadows which I hate. Not your fault, I think you did a pretty good job keeping it down. Just wish digital blue channels were better.
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Of course it's being used at 5600K for that warm fire look, if I wanted a neutral look I would have used straight 3200K lights. The point of the 2300K material was to show that even at it's worst it's totally useable.

Shot at T2, T1.4 on supers is a last resort.
 
Wow, I finally worked my way through this ugly thread. Tempted to comment a lot here and there, but it seems all my points have been covered by others. For those who have just joined us or skimmed to the end, here's a handy guide on how to read this thread: Go back to the beginning and read every post Graeme, Evin and Blair. Everything else is pretty much noise. No disrespect intended here, but I don't know how else to say it.

One final thing to throw out there that I have is this. Don't think of ISO in terms of "ISO" or "Exposure Index". That's not really how it works here since it is a metadata property we can change on a whim. When it all comes down to it, the ISO is really a reference point for where your mid-grey value is set along your exposure curve.

Starting at 800 is almost always the way to go in my experience. I don't change away from 800 all that often and usually need a pretty good reason to do so. But because of what ISO is to the RED system and how the MX sensor works, there is no true native ISO... I would say that 800 is an optimal setting for a variety of situations. But the correct ISO to use is whatever value gives the desired ability to monitor and expose your image for the best results. In my experience, everything from about 320 up to 1200 is valid. Outside those limits, you start to noticeably compress your exposure range on one end or the other.

If you're experiencing too much noise at 800, then a few things could be happening.... You're under-exposing. You need to get the camera up to temp and re-do the black shade calibration, etc..

If you think that your image is less noisy at 320 than at 800, don't be fooled by what's going on. These are meta applied settings, the noise is still there at 320, but with the lower grey point on your curve, you're compressing the dark detail and crushing the noise out. The sensor records the same thing, regardless of what you have your ISO set to.
 
Jeff Kilgroe said:
The sensor records the same thing, regardless of what you have your ISO set to.
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At this point in the Thread I think we all understand that ISO (during the Post/image processing transform) is technically just metadata and not an absolute. We get the semantics. But as you stated: the sensor records the same thing. Always. Because it has a fixed (finite) sensitivity to light. Period.

The real question of this Thread to many can be restated for clarity: how do we "rate" the EPIC's sensor ?
 
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