Pushing Dynamic Range to the limit

[steve green]

Hey guys,

I've got a challenging shoot coming up where I need to shoot a fountain at night which is backlit and under lit by bright tungsten lights. In the background is a dimly lit sculpture which needs to be seen in the final product. I cannot use any artificial lights at all to supplement the sculpture. My question is one of exposure and possibly HDRx. 1) Would it be better to expose for the dim sculpture and have say four stops of HDRx deal with the water (a lot of motion involved). 2) Use exposure check and not clip the water and deal with the sculpture in a color correction suite. 3) Set the exposure right in the middle, use a modest amount of HDRx (2 stops) and let the DR of the Epic and a powerful color correction balance it all out.

Any suggestions would be very much appreciated, I'm going to try and shoot some test the day before we shoot, but even with that I won't have the ability to take it into a post suite beforehand.

 

[John Marchant]

I would avoid relying on HDRx as the motion in the water will not look good with a narrow shutter, and its too random for post blur to work well.

Personally I'd shoot at ISO320 and expose as far to the right as I dared, with a single stop of HDRx to get me out of jail. If the main scene doesn't contain much motion I'd also consider a 360 shutter on the main exposure, so that the shutter angle on the water in the 'safety' hdr channel is normal.

 

[Mike P.]

Can you not shoot all three and use whichever one works best?

The problem is, if your goalposts are lit up it's either going to be noisy or completely gone. Something tells me because it's a practically lit night time shoot you're going to be running into underexposure more than overexposure (even with the lights on the fountain)... So with that in mind, I'd be exposing for the shadows and using hdrx to capture the highs. But again, testing should take no more than 5mins and you should be able to see what you can get out of the files in RCX right then and there (essentially realtime.)

 

[steve green]

I would avoid relying on HDRx as the motion in the water will not look good with a narrow shutter, and its too random for post blur to work well.

Personally I'd shoot at ISO320 and expose as far to the right as I dared, with a single stop of HDRx to get me out of jail. If the main scene doesn't contain much motion I'd also consider a 360 shutter on the main exposure, so that the shutter angle on the water in the 'safety' hdr channel is normal.

John,
Thanks for the suggestions, question though, doesn't Epic have a greater DR at 800 ISO? BTW, the main scene has a crazy amount of movement in the water so I'll have to go 180 degrees but I like the 360 degree idea for other possible applications in the future.

 

[John Marchant]

Changing the ISO just moves where your middle grey appears. Your overall dynamic range isn't affected by shooting at 320, but you will be balancing the image towards the shadows. Being very accurate to expose just to the very point of clipping in exposure check will give you the best possible clean image in the dark areas. HDRx of just a stop is enough to save you if something blows a tiny bit, without getting you into hot water from a grading point of view.

 

[steve green]

Can you not shoot all three and use whichever one works best?

The problem is, if your goalposts are lit up it's either going to be noisy or completely gone. Something tells me because it's a practically lit night time shoot you're going to be running into underexposure more than overexposure (even with the lights on the fountain)... So with that in mind, I'd be exposing for the shadows and using hdrx to capture the highs. But again, testing should take no more than 5mins and you should be able to see what you can get out of the files in RCX right then and there (essentially realtime.)

Mike,
I can test all three, but can't shoot all three as our needs dictate we shoot this from multiply angles. I'm concerned my basic ability in RCX won't really give me all the benefits of a final color correction in a proper suite with a knowledgable operator.

 

[steve green]

Changing the ISO just moves where your middle grey appears. Your overall dynamic range isn't affected by shooting at 320, but you will be balancing the image towards the shadows. Being very accurate to expose just to the very point of clipping in exposure check will give you the best possible clean image in the dark areas. HDRx of just a stop is enough to save you if something blows a tiny bit, without getting you into hot water from a grading point of view.

John,
I love that idea! I wouldn't have considered it but it makes perfect sense.

 

[Matt Ryan]

Rent a Sony F65

Troll. Every post is Anti-RED. Why are you on this forum wasting your life away?

 

[Marc-André Gray]

Rent a Sony F65

Great idea Steven... So are you going to mail him the money or wire transfer the difference in rental fee?

 

[steve green]

Changing the ISO just moves where your middle grey appears. Your overall dynamic range isn't affected by shooting at 320, but you will be balancing the image towards the shadows. Being very accurate to expose just to the very point of clipping in exposure check will give you the best possible clean image in the dark areas. HDRx of just a stop is enough to save you if something blows a tiny bit, without getting you into hot water from a grading point of view.

After further thought, won't that give me less highlight protection?

 

[John Marchant]

After further thought, won't that give me less highlight protection?

Less protection, sure. But if the exposure is stable, and it sounds like it could be, you don't need that protection. In that scenario highlight protection is just wasted empty space in your histogram.

 

[Timur Civan]

Rent a Sony F65

 

[steve green]

Less protection, sure. But if the exposure is stable, and it sounds like it could be, you don't need that protection. In that scenario highlight protection is just wasted empty space in your histogram.

Again, makes sense.

 

[Steven Veldkamp]

u mmad

Because the F65 offers a wider dynamic range where HDRx is no option.

Troll. Every post is Anti-RED. Why are you on this forum wasting your life away?

I own a Red Epic, that's why.

But let's not derail this thread with petty fanboyism. Any suggestion was welcome according to the OP.

 

[Matt Ryan]

I hate to tell you I'm not a fanboy....I don't own a RED camera and frequently use Alexa and other camera's. But every one of your posts is anti red, thus my comment.

He already stated what camera he was using so your suggestion was of no benefit to the OP.

 

[Hrvoje Simic]

I suggest dropping the 2)

If the statue is of any importance in the shot and you leave it for post to be digged out of the blacks, you are gambling with noise, especially with uncontrolled light factor.

The choice between 1) and 3) depends on priorities in the shot.

In any case, I don't suggest bothering with keeping all the data in fountain's highlights.

 

[steve green]

I suggest dropping the 2)

If the statue is of any importance in the shot and you leave it for post to be digged out of the blacks, you are gambling with noise, especially with uncontrolled light factor.

The choice between 1) and 3) depends on priorities in the shot.

In any case, I don't suggest bothering with keeping all the data in fountain's highlights.

There in lies the challenge, it's important to not have the water blow out.....I will have an opportunity of a test the day before we shoot so hopefully I can experiment with all the suggestions.

 

[Vance Colvig]

I would sure try to use a Dedo 150 (battery powered) to get some light on the statue from afar.

 

[steve green]

I would sure try to use a Dedo 150 (battery powered) to get some light on the statue from afar.

Nice try....not going to happen. No artificial light.

 

[Gavin Greenwalt]

Is this shot static? Move the camera so that you can see the statue. Shoot it with a lonnngggg expsoure so that it's nice and bright and clean. Shoot your FG water fountain. Composite the two together. Roto as needed.