No really... Overexpose or Underexpose the Red?

[Erick Stoll]

Having done significant amounts of reading on the subject of properly exposing the read, I have seen wildly different opinions, sometime within the same article! I've read all the threads, yet I can see no consensus. What is the best way to achieve a safe raw image that can be manipulated in post!? Inversely, what if one is looking to do the least amount of grading in post as possible?

 

[Evin Grant]

Both
You should give as much exposure as possible without clipping highlights.
You can get away with underexposure in 5600k light, but be more conservative in 3200k or use a CTB (1/4 blue) filter.

 

[Dominic Jones]

I would certainly steer clear of underexposure, as pulling the image up significantly will get very noisy results.

Ideally you want to:
* Shoot as close to 5000K as possible (daylight is fine)
* Not shoot for "printing up", but rather, in a low contrast scene, expose to the right, at least a little
* Avoiding compensating for exposure using the ISO settings if possible

Some will champion exposing to the right as a general rule, however, my personal preference is to attempt to expose the scene as you would like it to look after post, but to err on the side of over exposure, whilst of course protecting your highlights.

If you want to reduce noise as much as possible, make sure you've got adequate amounts of fill to allow you to crush the blacks down with a curve in post whilst still retaining shadow detail, as this will eliminate the majority of the noise in the image...

Happy shooting!
Dom.

EDIT: Lol, nice answer Evin - but a lot of sense there along with the humour!!

 

[Brandon Kraemer]

I can report that footage shot exterior (5600k) underexposed and transcoded full debayer from Redcine had plenty of detail and latitude when brought into Color. It was easy to expand the exposure range into a beautiful image, risking no loss of detail in the highlights, and not revealing much in the way of noise at all. In fact I saw less noise in the Blue shadows and highlights on the underexposed clips than I did in shots that would have been considered normally exposed.

 

[Brandon Fraley]

I would certainly steer clear of underexposure, as pulling the image up significantly will get very noisy results.

Ideally you want to:
* Shoot as close to 5000K as possible (daylight is fine)
* Not shoot for "printing up", but rather, in a low contrast scene, expose to the right, at least a little
* Avoiding compensating for exposure using the ISO settings if possible

Some will champion exposing to the right as a general rule, however, my personal preference is to attempt to expose the scene as you would like it to look after post, but to err on the side of over exposure, whilst of course protecting your highlights.

If you want to reduce noise as much as possible, make sure you've got adequate amounts of fill to allow you to crush the blacks down with a curve in post whilst still retaining shadow detail, as this will eliminate the majority of the noise in the image...

Happy shooting!
Dom.

EDIT: Lol, nice answer Evin - but a lot of sense there along with the humour!!

while I myself am not the most knowledgeable cinematographer, this would have been my answer as well. Try not to shoot above 320 ISO, add fill so you can crush, and if you're unable to add enough light to balance the picture, let your pings and windows blow out. Every situation is different, but these are my usual guidelines. ie, don't underexpose

 

[Erick Stoll]

Thanks for the info...
What is the deal with blue? Blue light often underexposes or overexposes? Thanks

 

[Jeff Kieffer]

Thanks for the info...
What is the deal with blue? Blue light often underexposes or overexposes? Thanks

Hi,

The blue channel of the RED is the weakest as the camera works best under Daylight. If you shoot 3200°K the blue noise will come up first in the dark areas.

By adding a 80 series blue filter, your just help the camera to perform best.

Cheers,

Jeff

 

[Brandon Fraley]

Thanks for the info...
What is the deal with blue? Blue light often underexposes or overexposes? Thanks

the blue channel is the most light hungry, so if you shoot under tungsten, the blue channel won't get enough blue light, and will be the first channel to show noise. Always remember to make sure your blue channel is getting enough light.

Some people use a filter, I'm not sure what the consensus is on this, but to me it doesn't make a lot of sense, since a filter simply "filters" out that color, so your cutting out orange light, not producing more blue light. Either way you're going to need to add more light. Doesn't really make a lot of sense to me to use a filter.

 

[Harry Lipnick]

the blue channel is the most light hungry, so if you shoot under tungsten, the blue channel won't get enough blue light, and will be the first channel to show noise. Always remember to make sure your blue channel is getting enough light.

Some people use a filter, I'm not sure what the consensus is on this, but to me it doesn't make a lot of sense, since a filter simply "filters" out that color, so your cutting out orange light, not producing more blue light. Either way you're going to need to add more light. Doesn't really make a lot of sense to me to use a filter.

If the choice is between having a decent exposure with noisy blues, or having a fully underexposed image, I think it's a fairly obvious choice. The time to use the blue filter is when you can afford to cut a stop or so while maintaining a healthy exposure. Of course you are cutting out orange light, not adding blue, but by doing this, you are balancing the light to better suit the needs of the RED's chip. Essentially, the filter brings each channel's "ISO" to the same rating, so to speak, if that makes any sense.
Peace,

-Harry

 

[Alex Curran]

So if the blue channel is not getting enough light and your shooting 3200k, does it help if you add CTB(1/4 or 1/2) to some(not all) of your lamps?

 

[Harry Lipnick]

So if the blue channel is not getting enough light and your shooting 3200k, does it help if you add CTB(1/4 or 1/2) to some(not all) of your lamps?

Not exactly. When you gel only a couple lights, you're changing the relative temperatures between sources in the scene. What your attempting to do, at least insofar as noise is concerned, is trying to change the "white" for the sensor. So by using a blue camera filter on the lens (or the same exact gel on all the lights, if you wanna go that way) you're basically optically changing the camera's white balance. This will leave your blue light energy alone, but cut down red and green wavelengths, which will balance the exposure of the channels. Your shot may then be a bit underexposed, but then this will allow you to open up another stop, without blowing anything out. Hope this helps.
Peace,

-Harry

 

[Kevin Wild]

If that is the only choice, I say overexpose a bit on your hightlights. I have done a TON of correcting run and gun stuff this past week, where lighting was not possible (shot at a hospital). While it does have a ton of latitude, the RED still does not do that great with little light. I was surprised how much grain we are getting by bringing the ASA/ISO up to 500, exposing up a bit in post and tweaking ever so slightly the lowest curve. Obviously, all of these induce noise and together induce a LOT, but I had to do it to get any type of picture some times.

(Some shots were of nurses visiting patients at home. NO lights! Just a lamp in a room or something. While I'm not sure any camera would be able to do "great" on this, I was suprised how much grain was there when I got it to a view-able level.)

 

[Brandon Fraley]

So if the blue channel is not getting enough light and your shooting 3200k, does it help if you add CTB(1/4 or 1/2) to some(not all) of your lamps?

the best thing to do is have a daylight balanced kit (what I've done) and get some daylight balanced screw in bulbs to replace bulbs in desk lamps or other lights. Remember that gelling fixtures or using a filter in front of the lens FILTERS the light to just the blue spectrum, causing you to lose a lot of light. Using a naturally daylight balanced fixture means you get the same amount of watts, and as is usually the case, the fixtures are much more energy efficient (flos, LEDs, etc.)

 

[Daniel Browning]

What is the best way to achieve a safe raw image that can be manipulated in post!?

• What is the best temperature to cook a meal?
• What is the best speed to drive a car?
• What is the best amount of time with a friend?
• What is the best exposure for RED ONE?

It depends. It depends. It depends. It depends.

More heat for steak. Less for ice cream.
More speed on the race track. Less in a school zone.
Hours with one friend. Days with another.
Underexposure in one shot. Overexposure in the next.

It depends. IMHO, the best advice is:

Simple: ISO 320.
Simple and best: ETTR.

Every camera has a certain amount of dynamic range. For the best results, you must choose how much highlight headroom you need for the shot and expose accordingly. More highlights ("underexposure") means less shadows. More shadows ("overexposure") means less highlights.

Dark gray subject on a gray set with gray props and a gray background and soft lighting? Overexpose (even ISO 50) for less noise, more dynamic range, and more footroom.

White subject on a white set with white props and a white background and harsh lighting and shadows? Underexpose (ISO 640 if needed) for more highlight headroom.

Again, it comes down to ETTR.

 

[Erick Stoll]

• What is the best temperature to cook a meal?
• What is the best speed to drive a car?
• What is the best amount of time with a friend?
• What is the best exposure for RED ONE?

Is 320 the answer to all of these questions?

But seriously, I understand the relevance of your answer, I just don't have my hands on a Red, and am going to be shooting on one in June without having more than a day with my hands on it. Just trying to get direct answers!

 

[PatC]

My simple addition is don't clip your highlights.

 

[Raul Gonzo]

the best thing to do is have a daylight balanced kit ...

Yes, this has helped me tremendously...

 

[Shane Smith]

A lot of great info here. Thanks guys, will help as I get ready for my first real shoot with the red in a week.

 

[Brandon Fraley]

Just trying to get direct answers!

don't interpret his response as condescension there's strong info in the second half of his post.

 

[Pietro Impagliazzo]

Is everyone shooting with RED rating the camera as ISO 320? Anyone rating at ISO 500?

I don't think the noise would be that bad, specially downscaling from 4K to SD or even 1080p.

I've read that rating the meter at 320 would not give the right exposure in the RED One, is that because of all the color space problematics?