a cinematography question

[Shapour Daneshmand]

need enlightenment from some of you great cinematographers.
i believe that in order to get best performance from a lens, we need to put the iris around 4.5 , 5.6. is that right
i also believe that to get the best image from RED sensor is to expose it for ISO 250. is that right?

if both these assumptions are right but the amount of light only allows you to choose one of these options, which one would you choose?
thank you in advance for the time you will be taking to respond.

 

[Michael Lindsay]

From a dry techniclal pov the 2 stops down lens rule (...where your 4.5, 5.6 suggestion comes from) is nearly usefull if you want sharp contrasty clean images.... that is often not the case.

Even on the 1st Red camera Red 1 (old chip early build) many have created interesting/beautiful images at much higher Iso settings...

Post some images/links/refs you like and many here will jump in with 'how to' suggestions...

PS Many here like to shoot wide open and some love deap stops.... some lenses perform well wide open and some lenses perfrom 'interesting' wide open

PPS

I mostly rated the Red 1 at 320asa (@4k 4500-7000kelvin)
I mostly rated the Red 1 MX at 500 asa (@4k 4000-7000kelvin)
I mostly rate the Epic MX at 640 asa (@5k 4000-7000kelvin)
I currently working with the Epic Dragon V2olpf at 500 asa (@5k 3800-7000kelvin)

 

[Michael Tiemann]

need enlightenment from some of you great cinematographers.
i believe that in order to get best performance from a lens, we need to put the iris around 4.5 , 5.6. is that right
i also believe that to get the best image from RED sensor is to expose it for ISO 250. is that right?

if both these assumptions are right but the amount of light only allows you to choose one of these options, which one would you choose?
thank you in advance for the time you will be taking to respond.

The answer is simple: swap out your under-powered lights for more powerful ones ;-)

More seriously...

If by "performance" you mean maximizing the information you can record from a lens test chart, then, generally, stopping down two stops from wide open yields the highest contrast (or MTF )modulation transfer function)) at both lower and higher spatial frequency ranges. And if shooting a resolution chart is your objective, you can lower your frame rate to 1fps, shoot with a 360 degree shutting, and ISO 250 should be plenty of sensitivity.

However, most great-looking scenes do not come about because of great MTF specs alone. They come about because the selective focus, composition, lighting, and imaging all work well together. You anticipate this answer by asking which compromises to choose, so here are some of the considerations:

A shallow depth of field can make the in-focus image look *very* in focus because it contrasts so strongly with all the out of focus stuff. On an absolute level, a wide-open lens may resolve fewer lp/mm than a stopped-down lens, but on a relative level, there's nothing like a good wide-open lens to focus the eye on the detail you want the viewer to see.

On the other hand, there are times you want to have a lot of the frame in focus--especially for an establishing shot. Stopping down is one way to get there. Shooting with a wider angle lens and cropping the sensor is another. Both can be used in conjunction. Red cameras have plenty of resolution to make that work.

Shutter angle is another variable. Most of the time this is 180 degrees, or 1/48th of a second at 24 fps. But open it up to 360 degrees and you get another stop of light, at the cost of different motion characteristics. This might be OK, or it might be a problem. But it's part of the mix.

As for the RED sensor, I'm really only familiar with DRAGON, which, paraphrasing Phil Holland, works more like film than film. If you don't mind a little "grain", then you can push it. If you want it really clean, then rate it low and hit it hard. Again, while one can argue about absolute levels of resolution, the real question--which is suggested by your appeal to cinematographers as opposed to lab-bench scientists--is what is appropriate/not appropriate for your subject. Great cinematographers make art from the limits imposed on them. A movie that works at ISO 250 but would fall apart because of the increased noise of shooting ISO 500 is probably not a very strong movie.

And finally, don't be fooled into thinking that everybody else is getting great results just by having a good sensor and fast lens. Cinematography is as much about lighting as it is about shooting. Buying a RED camera without a suitable lighting package is like buying a Ferrari without budgeting for gas.

 

[Hal Long]

Good responses from Michael and Michael. Not much to add there.

ISO: Red MX sensor (Epic, Red One MX, Scarlet) is native 800. If you rate it at 320, expect your latitude to shift. Unlike some other cameras, there's not really a gain applied to the image by the ISO setting. It's merely shifting the center of your exposure up and down the curve. It's the same thing as opening up a clip in RED-Cine X and sliding the ISO at that stage. The image captured is the same, it's just how you decide to push or pull the exposure and once you're off the native iso much of the ISO changes in camera is a latitude adjustment.

Lenses: The sweet spot in most lenses is two stops from open. Michael nailed it. Subjectively, this is because many lenses have more "issues" wide open (sharpness, aberrations). So with most sub-premium (MPs, S4/5s, Leica) many DPs stop down at least a stop from wide. That said, wide open (WFO) sometimes just looks just right and often it's because of the issues, especially when dealing with super speeds.

Cheers,

H

 

[joey richey]

"Great cinematographers make art from the limits imposed on them."

such a great piece of information. thanks guys, for your insight!

 

[Noel R.]

One difference I've noticed between iso 320 and 800 besides less noise is that at 320 you get an image that has more contrast and saturation. Some people like that while others prefer the look at 800 with less contrast and saturation. That's also another factor that can affect your look and can sometimes be used creatively rather than which is better. Just be careful underexposing at iso 800 in low light. It leaves you little room to push the image in post.

 

[David Mullen ASC]

There are times when the concept of "best" becomes overly reductive. With many sensors, "best" for minimal noise is not "best" for highlight latitude. The best image is the one that accomplishes what the artist hoped to achieve with that image, and that doesn't always mean the sharpest or cleanest.

 

[George Butterfield]

need enlightenment from some of you great cinematographers.
i believe that in order to get best performance from a lens, we need to put the iris around 4.5 , 5.6. is that right
i also believe that to get the best image from RED sensor is to expose it for ISO 250. is that right?

if both these assumptions are right but the amount of light only allows you to choose one of these options, which one would you choose?
thank you in advance for the time you will be taking to respond.

Put the lens aperture at the middle setting. Put the iso at 800. Add or take away light as needed. Then make corrections in RedCineX.
if you don't want to do it that way ... put iso at 800 and set lens aperture as desired.
(make a fat negative between the goal posts)
if it's T&A none of this matters ...

 

[Phil Holland]

I find the key to success in creating expected image quality is knowing the camera system and the lenses.

Technically speaking, yes, at about 2 stops in you're looking at the "sweet spot" on a lens. However, that means you are ignoring creative possibilities that can be unlocked by shooting and exposing wider open or more stopped down.

The same can be said about rating your ISO as it can influence the feel of the material and of course general captured dynamic range and workable latitude.

For me personally, testing has yielded the most useful information about how to proceed with any camera and lens. This is also true for lighting, though we don't talk too much about it round these parts. I do actually spend the vast majority of my free time exploring lighting and the possibilities it presents to apply it on future shoots.

For Red cameras, testing and getting very familiar with the in camera exposure tools will save your sanity and provide predictable results. My last half a dozen shoots had nearly zero exposure compensation in post because exposure was nailed on the day. The workable latitude was merely explored in adding tone and manipulating color slightly. Shooting carefully allows for more possibilities in terms of general image quality and further manipulation in post if you desire it.

 

[Max Lapointe]

800 ISO and two stops from WO is the sweet spot. Read some MTF charts and sometimes, that sweet spot on a lens will be 3 stops from WO. Really depends on the glass. Great information all over.

 

[Nick Morrison]

The best image is the one that accomplishes what the artist hoped to achieve with that image, and that doesn't always mean the sharpest or cleanest.

Love this. So much.

 

[Robert Ruffo New]

One difference I've noticed between iso 320 and 800 besides less noise is that at 320 you get an image that has more contrast and saturation. Some people like that while others prefer the look at 800 with less contrast and saturation. That's also another factor that can affect your look and can sometimes be used creatively rather than which is better. Just be careful underexposing at iso 800 in low light. It leaves you little room to push the image in post.

You can get that saturation back with a quick grade

 

[Daniel Reed]

The best image is the one that accomplishes what the artist hoped to achieve with that image, and that doesn't always mean the sharpest or cleanest.

Great comments by all, especially the quote by David - i may have to borrow it!

Buying a RED camera without a suitable lighting package is like buying a Ferrari without budgeting for gas.

I completely agree about the importance of lighting; however; I'm not sure if buying lights makes a lot of sense if you live anywhere remotely near a rental house.

Lights, grip and electrical gear are big, heavy, take up space and can be quite expensive.
If liability/inland marine insurance is purchased, which it seriously should be, equipment can be rented for dollars on the hundreds.

Unless you're shooting for pay most days of the week, do you really need a dozen C-Stands?... Do you need to own a handful of HMIs... what about that $3K hazer you use once in a blue moon?!

Just thinking out loud. For me, I like the flexibility of trying out and mixing as many lighting options a rental house can offer - feels creatively liberating :thumbsup:

 

[Michael Tiemann]

Daniel, what I should have said is "Buying a RED camera without using a suitable lighting package is like buying a Ferrari without budgeting for gas." I don't care whether you buy or rent lights...but it annoys me when I see so many people naively believing that 16 stops of DR means that suddenly lighting is irrelevant, and we can get everything into the sensor that our notoriously lying eyes tell us they are seeing when we look at the scene in available light.

 

[Lakis Amarantithis]

I like to compare everything to cars some times as it's easy to understand because all of us drive.
Saying shoot with this ASA and this speed is like saying go 55mph under the sun and you'll be ok. Generally is true.

I agree 100% with David and Phil.

You need to learn the camera really good then the lenses even better as each lens has a different personality (if you are like me who likes to play with all kinds of lenses).
Some times you want 1000iso and some times 50iso, some times you do want a blurry pic and other times a super sharp. As the script demands the camera should create.

 

[Noel R.]

You can get that saturation back with a quick grade

You can increase saturation in post, yes, but it usually doesn't look the same. There is a difference between saturating you image in post and feeding your sensor light. It's not the same look. Not saying either way is right or wrong but I feel it's better to get as close as you can to the final image you want in camera than in post.