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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 :)

question to graeme or deanan? TED said:rate red 250 in low con and 400+ in high con

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Cüneyt Kaya

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here is the quote:

I’m explaining to people on a pretty regular basis that the RED is kind of like 2 cameras in one – one camera for low contrast, low DR photography where you can rate from 250 ASA on down as long as you don’t overexpose, and use the Raw View mode in the camera to check the levels, and have really nice imagery – learning to use the histogram on the right side (the right 3rd of the of the histogram scale) for low con imagery can be your best friend...

... and one camera for high contrast, high DR challenging photography where you have a huge range from under to over, and you can expose at 400 ASA or higher, and as long as you don’t clip the highlights, you will be amazed at how much range you have in the mids and shadows to work with... This camera is way more sensitive that people give it credit for under the proper high contrast shooting conditions... Using the histogram from 2/3’s full on down for high DR photography can be your best friend.

The biggest mistake I see people make is letting things blow out because they are worried about the shadows, those shadows can hold clean and gorgeous like crazy – I see it all the time on properly exposed high DR imagery.

If you use REDspace for your overall exposure setting, and use RAW View for checking highlights as you work and check exposures you will have effectively done what MacGregor describes in his Rec709 at 640ASA testing. REDspace for all types of photography can be your best friend, when used in tandem with checking highlight exposure in RAW.

The RED ONE has various “sweet spots” for exposure depending on the various contrast conditions, color temperature of light being used and a number of other creative factors – that’s one of the reasons it’s such a nice tool to work with. The more testing and experimentation a DP has time to do, the more they learn about how far the can push and pull the images to create the look and feel they want – the joy of RAW cinematography.

+ Ted

here is the thread
http://reduser.net/forum/showthread.php?t=28705&page=5

and mac says
"View RAW seems to be just like if you set the camera to 250ISO, camera RGB, 5000ºK and any other value set to default. That´s why if you use false colour with this view (which you shouldn´t use btw) will give you a real world ISO of something like 100.

http://reduser.net/forum/showthread.php?t=28705&page=12
__________________
so why?

an explanation is needed here.
How does a digital sensor work related to a ASA rating and Contrast of a scene?
And after the explanation, how to use a lighmeter correctly with red knowing this explanation...
and how to rate if you are only shooting RAW VIEW so the oldschool DOP`s lighmeter match.
 
It's all about where you place mid grey and how much highlight versus shadow range you want.
 
Right exposures with false color and raw mode

Right exposures with false color and raw mode

Deanan said:
It's all about where you place mid grey and how much highlight versus shadow range you want.
Click to expand...

Deanan,

I was told in this user forum that the false color and raw mode is not the exact replication of the exposures. Is it true and if yes what's the best method to expose Red One with false color.

Currently exposing with histogram!
 
Basically, the higher the ISO, the more highlight protection you get. Each stop you increase the ISO, you gain a stop highlight protection. When there's low contrast you want to expose to the right, ETTR, which necessitates thinking of the camera as a lower ISO.

I'd not ETTR by adjusting ISO though, but use the raw clip meter or histogram in RAW to achieve it precisely.

Graeme
 
Can someone explain this in greater detail with a few histogram pics and stills? I can tell this topic is extremely important and want to make sure I understand. The more everyone understands this, the better will be Red's quality perception in the marketplace. I have heard that even some famous DP's still aren't exposing Red footage properly and perhaps that is due to a lack of practical application examples of this topic. If I'm the only one that still isn't 100% sure what all of this means and how to properly expose Red footage in different lighting situations, then please at least explain it to me. ;)

In particular, are filters essential to protecting highlights and shadows and acheiving a rich center-weighted histogram. Is a center-weighted, spread-out between 5 and 95 optimal for all shooting situations? Probably not. So how should the histogram look in a few common scenarios? Also, how do you switch the exposure meter and histogram showing on the EVF between RAW and say RedSpace or REC709? Is that possible? What menu? Finally, how can you tell if you have adequately exposed color for optimal grading and finishing in addition to optimal light exposure?

Please, please advise. I know this is perhaps the most important thing for me to learn right now, other than improving content quality of course. ;)

"I'd rather over expose a great scene than perfectly expose a mediocre one."

-michael zaletel
(shooter)
 
Ditto Michael's post! :)
 
You're not changing your contrast or dynamic range with different ISO ratings, you are merely protecting more highlight detail with higher ratings, at the expense of the shadow detail (and noise.) It makes sense to some degree to use higher ISO ratings in bright daylight in that hot highlights tend to be more common than really dark shadows. Though you get into the problem of needing heavy ND in order to avoid being stopped down too much.
 
Thanks for the link Nomad. Within that article was a link to another valuable article based upon a very long discussion the author had with Thomas Knoll (author of Photoshop and Camera RAW) regarding exposure on linear devices.

Expose to the right.
http://www.luminous-landscape.com/tutorials/expose-right.shtml

Excerpt:

"A 12 bit image is capable of recording 4,096 (2^12) discrete tonal values. One would think that therefore each F/Stop of the 5 stop range would be able to record some 850 (4096 / 5) of these steps. But, alas, this is not the case. The way that it really works is that the first (brightest) stop's worth of data contains 2048 of these steps — fully half of those available.

Why? Because CCD and CMOS chips are linear devices. And, of course, each F/Stop records half of the light of the previous one, and therefore half the remaining data space available. This little table tells the tale.

This realization carries with it a number of important lessons, the most important of them being that if you do not use the right-hand fifth of the histogram for recording some of your image you are in fact wasting fully half of the available encoding levels of your camera.

The simple lesson to be learned from this is to bias your exposures so that the histogram is snugged up to the right, but not to the point that the highlights are blown. This can usually be seen by the flashing alert on most camera review screens. Just back off so that the flashing stops."


Does all of this apply to the RED ONE sensor or are there differences to be considered?

Please advise, Graeme?

-michael zaletel
(shooter)
 
Exposing to the right is generally good advice for the RED One.

Graeme
 
The REDs sensor is linear as well, and the RAW data too.

But don't "overprotect" your highlights. Small light sources or reflections shouldn't be a reason to underexpose all the rest, since large areas of our scene might drop into noise. That's why the "traffic-lights" only come up if more than 1% of the image area are affected.

But use your own judgement, content is king!
 
This excerpt was helpful as well. Thanks again Nomad. :)

The following explanation by Bruce Lindbloom may help you understand what's going on with the above technique...

"For film based photography, the highlight end of the scale is compressed by the shoulder portion of the D/log E curve. So as brighter and brighter objects are photographed, the highlight detail gets gradually compressed more and more until eventually the film saturates. But up until that point, the highlight compression progresses in a gradual fashion.

Solid state sensors in digital cameras behave very differently. As light falls on a sensor, a charge either accumulates or dissipates (depending on the sensor technology). Its response is well behaved right up until the point of saturation, at which time it abruptly stops. There is no forgiveness by gradually backing off, as was the case with film.

Because of this difference, setting up the exposure using an 18% gray card (as is typically done with film) does not work so well with a digital camera. You will get better results if you set your exposure such that the whitest white in the scene comes close to, but not quite reaching, the full digital scale (255 for 8-bit capture, 65535 for 16-bit capture). Base the exposure on the highlight for a digital camera, and a mid-tone (e.g. 18% gray card) for a film camera."

Now if I can just apply the same "proper exposure" principles to my scripts, sets, sfx and scoring. :)

-michael zaletel
(shooter)
 
More good readings about our favorite topic:

David Battistella : Exposing the RED: Perfect Exposure, Every Time>>>(must search at Google>>>)

Basic rules of exposure>>>

- REDspace and RAW>>>Stuart English>>RED Workflow Wizard>>>

- Exposing>>>Stuart English>>RED Workflow Wizard>>>

- Colour space>>>Graeme Nattress>>>RED Problem Solver

- The skill of exposure>>>Graeme Nattress>>>RED Problem Solver>>>

- Exposing for the RAW format>>>Rob Lohman>>>Red Team>>>

ISO is metadata>>>Graeme Nattress>>>

Exposure differences between RAW - RED SPACE>>>

Setting the right ISO is important>>Graeme Nattress>>>

Digital Cinema Dynamic Range>>Stu Maschwitz

Determining ISO>>>Evin Grant>>>

Raw and saturation question>>David Mullen ASC>>>

RED colour space workflow>>Graeme Nattress>>

Clipping highlights 1>>Graeme Nattress>>

Clipping highlights 2>>Graeme Nattress>>

Exposing RED 1>>David Mullen ASC>>

Exposing RED 2>>Ian Bloom>>>

Exposing RED 3>>Mark Crabtree>>>

Grain/noise not problem but aspect of low light shooting>>D. Gregor Hagey csc>>
 
Thomas Knoll said:
A 12 bit image is capable of recording 4,096 (2^12) discrete tonal values. One would think that therefore each F/Stop of the 5 stop range would be able to record some 850 (4096 / 5) of these steps. But, alas, this is not the case. The way that it really works is that the first (brightest) stop's worth of data contains 2048 of these steps — fully half of those available.

Why? Because CCD and CMOS chips are linear devices. And, of course, each F/Stop records half of the light of the previous one, and therefore half the remaining data space available. This little table tells the tale.

This realization carries with it a number of important lessons, the most important of them being that if you do not use the right-hand fifth of the histogram for recording some of your image you are in fact wasting fully half of the available encoding levels of your camera.

The simple lesson to be learned from this is to bias your exposures so that the histogram is snugged up to the right, but not to the point that the highlights are blown.
Click to expand...

There is lots of good information from the Luminous Landscape, but this particular bit of information is incorrect.

ETTR improves the image because it results in more light (more photons); the number of steps/levels has no effect. This is all explained in great detail here:

The Consequences of Noise
 
Graeme Nattress said:
Exposing to the right is generally good advice for the RED One.

Graeme
Click to expand...

Ted and Graeme are totally right. "change the ISO ratng depending on the contrast of the scene" and "expose to the right" are basically two ways of saying the same thing: "Give the sensor as much light as you can without clipping"

The first exterior shot I ever took was across a very foggy lake. Very small range of stops in the scene. I exposed once at 400iso, and once at 100iso. Results were remarkably different noise-whise.
Looking at the shots in post, the 400iso shot looked like what you'd expect if you shot really fast but grainy film.(early build).
The 100ISO shot looked like creamy 50iso film.
As the were no nasty highlights in the scene to worry about, darkening down the monitor by changing tge ISO,but keeping an eye on clipping in the histogram yeilded fantastic results. I learned a lot from that about maximizing results from the red one.
 
Yes, different ways of saying and looking at exactly the same exposure philosophy.

Graeme
 
Mark Pugh said:
Ted and Graeme are totally right. "change the ISO ratng depending on the contrast of the scene" and "expose to the right" are basically two ways of saying the same thing: "Give the sensor as much light as you can without clipping"
Click to expand...

That doesn't sound right to me -- I'd like someone to explain why higher contrast scenes benefit from higher ASA ratings, because it seems to me that the dynamic range of the sensor is a constant and all you are doing is deciding whether to capture more highlight or more shadow information by playing around with the ASA rating. But you can't extend the dynamic range being captured with higher ASA ratings.

So what does low contrast versus high contrast have to do with ASA ratings? Are you basically saying that with a low contrast situation, you have more freedom to push the image "to the right" exposure-wise because you don't have hot highlights to worry about? But that really doesn't mean you are extending dynamic range in high contrast situation by using a higher ASA rating and thus exposing more "to the left" to protect the hot spots.
 
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