HDRx or increase ISO for highlight protection?

[Brandon J.F.]

I'm shooting a scene inside a burned down old house. The windows are knocked out and a wall is partially down. There really is no way to light the inside and I don't want to blow out the outdoors. I'm using a Scarlet so I would prefer not to use HDRx since I would have to shoot at 3k resolution.

I was reading that by shooting at a higher ISO and adjusting the iris to compensate you can get some highlight protection. Has anyone tried this in place of a stop or two of HDRx? I understand the image would be noisier and that's OK. I would rather have a bit of noise than shoot at 3k.

I would really appreciate any advice you guys can offer me.

 

[Bob Gundu]

regardless of what ISO you are going to shoot, the stop lights will tell you if you are blowing your highlights. You really have no choice but to expose for the windows and let the shadows fall where they may.

 

[Mike P.]

What about reflectors/bounce boards to help brighten the inside -- have someone under/beside the camera... Even a little light can make a huge difference. All else fails, can you block the scene out to be effectively told in silhouettes? The problem is, at ISOs above 800 you'll already be fighting noise and in this case there is bound to be more aggressively underexposed areas, which just makes matters worse. Plus, depending on the ISO needed to keep the interior from going too far under, you could be in a world of hurt.

The way I always imagined it working was that, you'd ETTR at ISO800 (or 1600 or whatever) and then bring down the ISO in post until your histogram was ETTCentre (thereby giving you more details in highlights that would be riding high at the recorded ISO.) That's perfectly awesome when the dynamic range doesn't exceed MX, however, when it does, you're either gonna get boned on the low-end or the high-end... one of them has to suffer (or you have to use fill to lessen the range of the scene.)

In other words, if you've got good noise reduction software expose for the highlights and be prepared to clean up the shadows. The thing about upping the ISO to retain highlights is that it won't be free. You would, essentially, get the same image from an ISO800 shot underexposed by a stop as you could from an ISO1600 shot exposed evenly... For example, all setting the cam to ISO1600 will do is make you think the shadows aren't underexposed at f5.6, whereas at ISO800 you would have to open up to f4.0... In that case, you could just shoot ISO800 at f5.6 and it'd look exactly the same as ISO1600/5.6 after your fiddle with ISO/flut in post... ...That doesn't help, does it?

 

[Brandon J.F.]

Thanks for the advice. I have reflectors and some LEDs that we can run off batteries (Cool Lights, etc). I'm also thinking about running some Christmas lights around on the floor in darker areas. It won't be much, but may help a bit.

 

[Joshua Reis]

How about netting or covering the windows with ND?

 

[Ketch Rossi]

To give a simple and quick answer, ISO and HDRX two completely different thing, they are not even RELATED...

HDRX is what you want, as it protects Highlights so that if you have a scene inside and outdoor in a sunny day it will give you extra DR to work with outside, and if the sun is shining down on water or reflective surfaces it will give you a way to protect those as well, this just few of the many applications.

ISO you use when you have no additional Lighting to apply to lit your scene and you are still too dark, but bringing the ISO up as a way to illuminate your scene will create NOISE, and past a certain barrier will simply not give you in off info to process properly, but before having no shot, then do use ISO, just don't just shoot one shot, do several at different ISO, even if it appears too dark, some times is better then get in it just right with too high of ISO, as it makes it harder in post.

 

[Brandon J.F.]

How about netting or covering the windows with ND?

That's not going to be possible. There is too much to cover and I'm in a very remote location.

To give a simple and quick answer, ISO and HDRX two completely different thing, they are not even RELATED...

I understand what HDRx is The only reason I asked about adjusting the ISO is because I read on Red.com and in several posts on this forum that if you increase the ISO (while adjusting the iris to compensate) you gain some highlight protection.

Thanks for the advice everyone.

 

[Victor MOREIRA]

I read on Red.com and in several posts on this forum that if you increase the ISO (while adjusting the iris to compensate) you gain some highlight protection.

Thanks for the advice everyone.

Knowing that ISO is metadata, i don't get how it protects your highlights... Maybe i'm missing something here. Stop lights are my best friend. Pushing ISO only gives me "virtual" noise. I keep shooting mostly at the native 800. In some cases, IF I DON'T HAVE lights or if i'm in a landscape situation with a huge DR need, i use HDRX. car shooting are good exemples of that type of HDRX use.

 

[Victor MOREIRA]

I would rather have a bit of noise than shoot at 3k.

In this case, i'm afraid that you're gonna get A LOT of noise. Looks like you are dealing with a big latitude to cover...

 

[Victor MOREIRA]

Shoot in 3K HDRX if your final output is 1080p. Rent an Epic and shoot HDRX if you REALLY need this in 4K.

 

[Bob Gundu]

When you get boxed in the corner you often need to put on your editing hat and think of creative ways to get the same idea across. By trying to get the best exposure might mean you need to intercut close up shots that don't have the problematic issues. A low camera on the ground just showing the feet as they walk by that also reveal details of the interior is a suggestion. Remember the barriers can become a good challenge that can become a brilliant idea!

 

[Brandon J.F.]

When you get boxed in the corner you often need to put on your editing hat and think of creative ways to get the same idea across. By trying to get the best exposure might mean you need to intercut close up shots that don't have the problematic issues. A low camera on the ground just showing the feet as they walk by that also reveal details of the interior is a suggestion. Remember the barriers can become a good challenge that can become a brilliant idea!

Great advice. Thanks Bob.

 

[Sam Eilertsen]

As I understand it ISO increases highlight protection simply by causing you to underexpose the sensor. It's no different than underexposing without raising the ISO and then bumping up it up in post -- the only difference is what you see in your monitor on set.

 

[Terry VerHaar]

Knowing that ISO is metadata, i don't get how it protects your highlights... Maybe i'm missing something here. Stop lights are my best friend. Pushing ISO only gives me "virtual" noise. I keep shooting mostly at the native 800. In some cases, IF I DON'T HAVE lights or if i'm in a landscape situation with a huge DR need, i use HDRX. car shooting are good exemples of that type of HDRX use.

If you look at the RED article on the subject, you see that raising the ISO lowers where middle grey falls in the sensor range thus providing highlight protection. The article, an excellent one, is here:

http://www.red.com/learn/red-101/exposure-with-red-cameras

 

[Victor MOREIRA]

If you look at the RED article on the subject, you see that raising the ISO lowers where middle grey falls in the sensor range thus providing highlight protection. The article, an excellent one, is here:

http://www.red.com/learn/red-101/exposure-with-red-cameras

Hi Terry,

I read the article before and just went through it again and again. As i understand it, Shooting at higher ISO is a kind of "method" for protecting highlights. The Raw data is unchanged. Higher ISO will only affect the displayed images on your monitor or your recording if you use an external recorder (Samurai, Pix 240). Shooting at higher ISO will "force" you to lower your aperture, protecting your highlights. I understand it as a "shift" of the danger zone to avoid clipping.

Hope i'm not wrong on this. I'm starting to doubt. Anyone else's POV ?

 

[James T Mather]

If you're shooting the characters into the highlight then they will be silhouetted on this side (there's not much getting around that) - Ask to position them so they stand out against the background as silhouettes and expose for the sky. When you come over shoulder (presumably now with a wall behind them) expose for the lit (daylight) side of their faces - letting the dark side fall completely away (maybe a poly to lift the tiniest amount but keep it down - remember you're matching to silhouette). This will preserve lighting continuity in the edit.

If the director doesn't like the sound of this tell him you need 2 18ks, a generator and a shitload of poly. Such are the realities of low budget production. Use the limits as strengths. I only hope the film isn't meant to be a brightly-lit feel good comedy.

For an example of this technique - offhand Godfather 3 when Andy Garcia is in an abandoned NYC kitchen. Unfortunately the fairy lights don't sound like they'll do much in daylight.

Alternatively: To fill a bit - try and get your hands on a roll of hammered/battered silver gel - it reflects back a softer light but still may make little difference depending on conditions (Hot clouds being the most awkward with the sun behind you as you look at the clouds). If you can't afford that, get your hands on several rolls of tinfoil/aluminum foil and place them on poly boards to throw back some fill (placed around the camera as a start) - using the duller side of the foil will give a more pleasing light and might boost your shadows a bit. If it's too much (Harsh) then crunch it up a bit - this will scatter the reflections around more randomly but will take some of the bite out of it. If it's not enough, use the shiny side (before you crunch it). It might look a little strong but might work if low enough on the exposure curve. Also don't discount mirrors as an option for throwing some stray sunlight around into those dark corners (or shiny metal which will soften the light a bit).

 

[James T Mather]

Hi Terry,

I read the article before and just went through it again and again. As i understand it, Shooting at higher ISO is a kind of "method" for protecting highlights. The Raw data is unchanged. Higher ISO will only affect the displayed images on your monitor or your recording if you use an external recorder (Samurai, Pix 240). Shooting at higher ISO will "force" you to lower your aperture, protecting your highlights. I understand it as a "shift" of the danger zone to avoid clipping.

Hope i'm not wrong on this. I'm starting to doubt. Anyone else's POV ?

Yes, it's exactly the same as lowering your exposure in native 320 ISO. Boosting ISO/ASA is only a way of looking at the RAW (much like gain on Video cameras). The raw remains unchanged regardless of ISO and can be switched around in post. Only exposure effects the RAW image. It's inclusion on the Red (as a standard) may come to be seen as legacy backward compatibility with film in years to come. It's just boosting the image you are looking at, at the expense of noise floor. In short - changing your ISO only effects the brightness of the viewed image.

Mild ad hoc crash course: Protect your highlights by making sure they are not clipping at 320ASA using the histogram, zebras or FC. If they are, then iris down/IR-ND until they are not clipping at 320 and see how bright your image is - if it's too dark then boost the ISO and see if you are within acceptable tolerances (I would have said up to around 1000asa or so - opinions will differ, as will the nature of the scene - the more you have to boost the noisier it gets - at 2000 unless you like noise it's probably getting tight) - If the image at 800-1000asa is acceptably bright to your eye then you are probably OK (in other words the image will hold up through post with a reasonable range and moderate to little noise). In short, by boosting ISO you are simply underexposing the 320asa and counting on the noise floor to hold up. It will break up eventually (around 1600-2000asa according to your aesthetic).

If not, then it's time to pull out HDRx or get lighting. I usually do the latter.

I usually stick to 320ASA (if I have a heavy LUT) or look at RAW a lot. That's the baseline that the camera runs at. Everything else is like force developing a neg in principle.



To recap: Don't let the RAW image clip (or 320asa). That's it in a nutshell.

 

[Brandon J.F.]

I finished the scene. We staged the action in the brighter rooms. I tried to expose for the actors faces as best I could without blowing out the windows. I kept the ISO at 800. No reflectors or ND on the windows. After we shot I did some quick color correction and was easily able to bring the light coming in through the windows down. The results really are great.

Thanks for all the advice everyone.

 

[Mike P.]

No stills of the scene, brandon? Awwww c'monnnnnn.... please?

 

[Bob Gundu]

Right on the money in your explanation James. It takes a lot of self experimentation to see exactly what the sensor is up to, and then just as much at your desk playing with what you can squeeze out of the files. It's not like your average camera, but you sure can get amazing results if you put some effort into it.

If you're shooting the characters into the highlight then they will be silhouetted on this side (there's not much getting around that) - Ask to position them so they stand out against the background as silhouettes and expose for the sky. When you come over shoulder (presumably now with a wall behind them) expose for the lit (daylight) side of their faces - letting the dark side fall completely away (maybe a poly to lift the tiniest amount but keep it down - remember you're matching to silhouette). This will preserve lighting continuity in the edit.

If the director doesn't like the sound of this tell him you need 2 18ks, a generator and a shitload of poly. Such are the realities of low budget production. Use the limits as strengths. I only hope the film isn't meant to be a brightly-lit feel good comedy.

For an example of this technique - offhand Godfather 3 when Andy Garcia is in an abandoned NYC kitchen. Unfortunately the fairy lights don't sound like they'll do much in daylight.

Alternatively: To fill a bit - try and get your hands on a roll of hammered/battered silver gel - it reflects back a softer light but still may make little difference depending on conditions (Hot clouds being the most awkward with the sun behind you as you look at the clouds). If you can't afford that, get your hands on several rolls of tinfoil/aluminum foil and place them on poly boards to throw back some fill (placed around the camera as a start) - using the duller side of the foil will give a more pleasing light and might boost your shadows a bit. If it's too much (Harsh) then crunch it up a bit - this will scatter the reflections around more randomly but will take some of the bite out of it. If it's not enough, use the shiny side (before you crunch it). It might look a little strong but might work if low enough on the exposure curve. Also don't discount mirrors as an option for throwing some stray sunlight around into those dark corners (or shiny metal which will soften the light a bit).