The search for a S35 frame

[Sean Porter]

Hey all,

So it may just be a legacy thing, but I've always wanted to get an actual S35 frame out of the Red. I like the idea of my lenses giving me the same FOV as they do on a film camera. The R1's sensor was a little too small, so with the Epic it seems like I could finally get there.

I did a bunch of research and the hardest thing was actually figuring out what, exactly, a S35 frame is. I was able to get the gate dimensions (24.9x14) but once the image is scanned, it seems the standard frame size is actually 24x13.5 (thanks to David Eubank)

I think there are two major benefits to setting up the camera this way:

1. Your lenses and your mattebox should behave as you expect, no vignetting.

2. When recording full 5K for S35, you end up recording a look-around which can be used to stabilize or repo shots later without eating into your resolution. I think this is one of the biggest advantages of shooting 5K.

After doing the math, to get the standard S35 frame size (24x13.5) the pixel resolution is 4444x2500. Seems like enough to get a good looking 4K finish.

I made this chart to be used as a reference when making custom framing guides in the camera. I wish Red would let us store more than one user frame guide!

As you can see the S35 frame barely fits into 5K 2:1. Personally I'd rather have the extra wiggle room in the recorded image, but if you need higher frame-rates...

Disclaimers:

I tweaked the full-gate frame size slightly (less than a .01%) to get a nicer pixel dimension.

pCam / David Eubank stated that the 1.85 extraction of S35 had a frame height of 12.980. My calculations gave me 12.972. I went with David's numbers =)

Anyway here is the chart if anyone is interested. Please post feedback or any errors you find.




Cheers,

[William Albertini]

Thanks for posting this...

[Chris Sharman]

This is really useful Sean - thanks.

For me I'd much rather work with a S35 sized sensor so that I know I will get what I expect out of my lenses. All the speculation of a full frame (35mm stills) Dragon sensor is a little bit worrying to me, hopefully they can cram the resolution into a S35 sensor so that we can keep using all our old lenses.

Cheers,

Chris

[Björn Benckert]

The Dragon and such will most likely have both higher pixel density and larger sensors. It's nothing to worry about. You can still shoot with the same poor quality as you do today. But I doubt that you would not like to shot larger formats if they where available. Just as any major DP or director would say no thanks to shoot on 65mm instead of 35mm film.

Very few people choose to shoot on 8mm if they got the money to shoot 35mm. Even less people shoot 35mm and zoom into the neg to make a 8mm crop. So when the dragon resolution is available to us then you will think the MX sensor is a bit small, does not give you the same nice DOF and so on. If red does not release the dragon somebody else will, when we get the 65mm sensors the smaller sensors will be seen as a second choice cameras. It already happen to Alexa, here in stockholm there is a few Alexa studio cameras available. And even for small commercial work DP's that likes the arri cameras demand the Studio version and only accept the regular Alexa if there is no studio version available. The same theory will apply to red cameras.

So RED please, let us order the dragon around NAB time. It would be perfect timing.

[Sean Porter]

Just as any major DP or director would say no thanks to shoot on 65mm instead of 35mm film.

Bjorn I hear what you are saying, and on some level sure, why not shoot 65 if you have the choice, but I think it's more complicated than that. Also major directors & DP's still choose S16 when they think it's the best fit for the story or their workflow, even if 35 (or even 65) is available to them. Big directors still have that choice even on film, and often choose 35 because it's right for the project. Shooting your ultra-wides on 65 or certain sequences as Christopher Nolan does makes sense. But even if he had the money to shoot 65 all the time, I don't know that he would? Back in the day 65 was used for pictures with big landscapes with lots of detail at a deep stop, ironically not for ultra-shallow DOF medium shots =)

With budget shrinking, on a 65mm sized-show almost everyone will be dependent on still lenses, so you'll loose the control and functionality of cine lenses, save a few rehoused Leica lenses out there. And if new full-frame lenses do come out, they'll be new and probably costly. You're 4x5 mattebox wont work for much wider than a 24mm, so you'll have to upgrade everything to 6x6. Not going to hand-hold that very easily. And since it's still low-budget, you'll most likely be shooting wide open a lot (or because you want the shallow DOF) and your AC's are going to be pretty beat up after every day, not to mention the risk of shots being unusable due to focus will be more of a problem. Getting a nice look is part of the DP's job, I think the other part is protecting the film's success and the directors choices in the edit room.

People are making movies every day on the 5D, so I'm not saying it's impossible, I just I'm just wondering if bigger is always better. Personally I'm more than happy with S35 for narrative work, and heaven forbid, I'm actually happy shooting mediums at a 2.8-4 split =)

Cheers,

[David Mullen ASC]

That's interesting... but I'd be more interested in the opposite, if someone would make some groundglasses for lens finders that actually match some of the recorded areas of the Epic so when I line up a shot, I don't have to ballpark the camera placement.

The fact that using a S35 area of the sensor gives you exactly the same view as on a S35 film camera to me seems less important, there is nothing magical about the S35 view of a 50mm lens, for example, compared to seeing bit more or less. But I do understand the value of lookaround and the ability to reposition a shot in post, though personally I like the compositional discipline of not having too much flexibility there, which is one reason I liked shooting 35mm anamorphic.

[Jon MIchael Puntervold]

It's nothing to worry about. You can still shoot with the same poor quality as you do today. But I doubt that you would not like to shot larger formats if they where available. Just as any major DP or director would say no thanks to shoot on 65mm instead of 35mm film.

I have a project coming up that I would like to shoot at Super-16 size, but no less than 3k resolution... Large formats does not fit all projects, and it does not fit all esthetics... sometimes a small sensor gives you a lot of benefits... Personally, super-35 feels perfect for most of projects I'm working on, but would it be cool to do something on a larger format, sure... maybe a western or a film about Zeppelins. It would be great in 65mm, but kitchen realism, no thank you, rather s16 than anything bigger...

[Sean Porter]

there is nothing magical about the S35 view of a 50mm lens, for example, compared to seeing bit more or less.

Thanks David for your thoughts, and your right there's nothing magical about it, except it's a standard that AKS and lens manufacturers have been using for a long time and something they could depend on. Once I had those guides set up, it was amazing to see how tight all the tolerances really were. But right at that the guide, the image works.

here with a 18mm speed panchro and an o-box:



I think they were heavily depending on that 27.536 diagonal =)

edit: as a side note, I was amazed how little the old 18mm vignetted at 5K. In this case the O-box is doing most of the dirty work.

Cheers,