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Jon O'Brien

Super 35 35-III

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Posted (edited)

Hi, anyone know if Arri 35-III cameras with Super 35 gates are optically centred - eg. the optical axis is dead-centre with the mid point of the Super 35 - eg. perf to perf - film frame) or if the axis is slightly off-centre due to the lens port positioned according to the dictates of the academy frame, wherein the lens is slightly offset because of the old-fashioned optical soundtrack? Sure, doesn't matter if you're going to be doing a DI or total digital post production but what if you were thinking of maybe shooting anamorphic and doing contact prints. Let's not even get into the economic madness of such an idea. I just want to know. Thanks!

Edited by Jon O'Brien

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21 hours ago, Jon O'Brien said:

Hi, anyone know if Arri 35-III cameras with Super 35 gates are optically centred - eg. the optical axis is dead-centre with the mid point of the Super 35 - eg. perf to perf - film frame) or if the axis is slightly off-centre due to the lens port positioned according to the dictates of the academy frame, wherein the lens is slightly offset because of the old-fashioned optical soundtrack? Sure, doesn't matter if you're going to be doing a DI or total digital post production but what if you were thinking of maybe shooting anamorphic and doing contact prints. Let's not even get into the economic madness of such an idea. I just want to know. Thanks!

Considering Arri 35III's are a very old and well used camera, I bet it would be hard to find one that hasn't been modified to run open gate super 35mm. Generally this is done by drilling new pilot holes into the housing that are slightly lower or higher then the stock holes with an offset. Thus, the lens mount can be adjusted between the two holes. With that said however, having had quite a few of those cameras brush through my hands recently at auction, I have noticed many were setup for normal 35mm. Remember, super 35mm can only be used for anamorphic without an optical reduction of some kind. For a digital workflow, Super 35mm is what you'd want to use because all of the scanners are designed for open gate super 35mm scans. 

You can shoot super 35mm with standard 2x anamorphic lenses. What ya get is 2.55:1 aspect ratio and it would be easy to take a pencil and lightly mark the are on the ground glass that would be over the 2.40:1 aspect ratio of release prints. When you make a contact print with no sound, of course it could be projected normally. The machine that makes the contact prints with the soundtrack, I don't think has a matte in it for the picture side.. it may, but I've never checked. This is why people who are doing an optical workflow, generally shoot NORMAL 35mm rather then super 35mm. Otherwise, why bother?  This maybe a question for Robert at Cinelab honestly, he can probably set the record straight on this one. 

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On 4/28/2019 at 9:30 AM, Jon O'Brien said:

Hi, anyone know if Arri 35-III cameras with Super 35 gates are optically centred - eg. the optical axis is dead-centre with the mid point of the Super 35..

If a camera has been converted to S35 (which should be noted on the camera or lens mount) it will have had the lens mount re-centred, but just because the gate is full aperture doesn't necessarily mean it's a S35 camera. At the last rental house I worked for, I think all of the 35-3s we had were fitted with full aperture gates, even though most of them were Normal 35. I was told this was because producers liked to have the ability to adjust framing when Cineon scanning and digital effects became more common in the 90s, and the soundtrack area could be masked out later if required.

I think only one of the half-dozen 35-3 cameras in the fleet was converted to Super 35. It wasn't a good camera to convert because the viewfinder didn't quite cover the enlarged frame, even with modifications to the ground glass holder and prism baffles. I believe P&S Technik did our conversion, which basically involved fitting an offset PL mount, modifying the ground glass holder and opening the viewfinder as much as possible to cover the new frame. The gate was already full aperture.

I have no idea about contact printers or whether they can mask the soundtrack area, but it wasn't a problem having full aperture gates in N35 cameras shooting anamorphic here in Australia.

 

4 hours ago, Tyler Purcell said:

Remember, super 35mm can only be used for anamorphic without an optical reduction of some kind. For a digital workflow, Super 35mm is what you'd want to use because all of the scanners are designed for open gate super 35mm scans. 

Every Scope ground glass I've ever seen is centred for N35,  I don't see any advantage to shooting anamorphic in Super 35,  just the hassle of having to mark a custom ground glass. The extracted 1.2:1 frame is no bigger, since with Scope the frame height is the restricting factor not the width, and a scanner will scan the full gate regardless of where your scope frame sits within that. So why use Super 35?

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10 hours ago, Dom Jaeger said:

Every Scope ground glass I've ever seen is centred for N35,  I don't see any advantage to shooting anamorphic in Super 35,  just the hassle of having to mark a custom ground glass. The extracted 1.2:1 frame is no bigger, since with Scope the frame height is the restricting factor not the width, and a scanner will scan the full gate regardless of where your scope frame sits within that. So why use Super 35?

Well yea, if you're extracting a 2.40:1 image, you'd use an academy ground glass. 

La La land used the full super 35mm width of 2.55:1 for their release. 

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1 hour ago, Tyler Purcell said:

Well yea, if you're extracting a 2.40:1 image, you'd use an academy ground glass. 

La La land used the full super 35mm width of 2.55:1 for their release. 

Given that the original 2.55 Cinemascope aspect ratio that La La Land paid homage to was shot on Academy cameras, there’s no need to use Super 35 for that either.

Academy is 1.37 so you could extract up to 2.74 from N35 with 2x anamorphic lenses.

La La Land would have required custom ground glasses marked up whether shot in N35 or S35, the choice was probably based  on what ground glass blanks were available.

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I’m sure La La Land extracted 2.55 : 1 from a Super-35 gate. The standard 35mm anamorphic gate is basically Academy in width but Full Aperture / Super-35 in height for a 1.20 : 1 area that is similar to the pre-Academy Fox Movietone aperture, before the Academy decided to trim the top & bottom. So sure, you could get 2.55 : 1 by cropping the top & bottom... but the original 2.55 : 1 CinemaScope format used the full height of the 4-perf negative and a bit more width than Academy. There would have been no reason for La La Land to not use a Super-35 gate since they were doing a D.I.

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So are you saying that in normal anamorphic mode with the lens mount centred to N35, Millenium XL2s are fitted with anamorphic gates that hard matte the exposure area to 1.20:1, rather than having a full aperture gate?

It's been well over a decade since I worked with Panavision film cameras, so I don't remember if we swapped out gates when we converted cameras between Super and Standard. I remember we had to swap fronts and mirrors, but I didn't think the gate was changed. 

Modern Arris all have full aperture gates whether set for N35 anamorphic or Super 35, the only time gates are changed is for 2 or 3 perf.

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Most modern 35mm cameras just have Super-35 / Full Aperture gates and if you order one set-up for standard 2.40 35mm anamorphic 4-perf, then the gate is centered (or offset) for Academy (sound projection).  So in theory you are exposing a 2.66 : 1 image on the negative but you are only composing for and using a 1.20 : 1 area to get a 2.40 image.  If you want, you can insert a 1.20 : 1 mask into the gate on a Panaflex or some Arris.

What I'm saying is that "La La Land" wanted a wider image than 2.40 so they were more likely to extract 2.55 from the Full Aperture gate than extract one from within a Normal 35mm / Academy gate or area, which would have meant both cropping the sides of Full Aperture but also the top & bottom of Full Aperture to get 2.55. There's no reason to do that if the gate is exposing Full Aperture, you just need to crop the sides from 2.66 down to 2.55.

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Yes, that's all I was saying too - they may well have used cameras set to S35, but given most if not all modern film cameras now are fitted with full aperture gates anyway, they could have used a camera with the mount and viewfinder frameline centred to Academy (as is the norm with 4 perf anamorphic) and still extracted a 2.55:1 frame.

Sorry, I was confused that you were saying La La Land would choose S35 because N35 anamorphic would use an anamorphic gate that would crop the exposed area to 1.2:1. I don't think anamorphic gates are even available anymore, there are just optional gate masks, as you say.

The most likely reason La La Land would use cameras centred to S35 in my mind would be because it makes more sense to have equal wiggle room on both sides, and given the ground glass had to be custom marked anyway they weren't locked in to the normal anamorphic camera set-up.

 

 

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You said “Academy is 1.37 so you could extract up to 2.74 from N35 with 2x anamorphic lenses.” Which implies they would extract 2.55 from within Academy, but you meant you could extract 2.55 from a full aperture gate even if centered for Academy, not that they’d extract 2.55 within Academy or within N35.

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Posted (edited)

How might a camera technician decide the case, with an older camera like a 35-III? A complete layman might perhaps attempt something like a plumb-bob dangling down through the lens mount, the string centered by eye in the approximate mid-point of the lens mount, and see if the point of the weight was in the center of the gate (assuming a S35 gate), or off-set. Forgive my inexperienced ruminations on how one could figure out by eye where the optical axis fell on the frame area. I suppose really all you could do is shoot a short test strip with a zoom and see if the image behaved off-axis during zooming.

Edited by Jon O'Brien

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There’s a better method. You set the camera up with a lens attached and shine light from behind the gate through the lens to get a projection of the aperture on a piece of paper or carton. A torch light, maybe a mirror, and a snippet of clear film that you have matted on a pumice stone (and well cleaned before inserting it in the canal) complete the action. Now you draw out the frame on the carton, draw the measured center lines of height and width, and after having pulled away the curtains for light on the carton you have a look through the finder. The Arriflex 35 III being a reflex camera you will see whether aperture, lens, and finder align. The best way is to film a reference chart, reinsert the processed film heads up and project it back onto the chart. That will reveal an off-axis lens.

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The lens mount or camera should be marked as Super 35 if it has been converted. 

To accurately check centring, many rental houses had a Bayonet or PL or PV mount borescope that would allow you to focus on a test film placed in the gate with a centre cross hair marked. If you worked on film cameras you often needed to adjust the floating inner midrib relative to the mount. The borescope tool would have optics with it's own crosshair showing the centre of the lens port. 

At a more basic level, the ground glass fitted should match the centring, so if it's a N35 ground glass fitted you can assume the camera is not set to S35, or has not been converted. With 35-3s, the original N35 ground glass was not as wide as a S35 one, and the whole ground glass holder assembly needed modification to accept the wider S35 ground glass. 

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One could make a tool that could check the lens centering pretty easy out of plastic bits and a drill press. Ya just need to make sure it's perfectly centered. 

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Thanks guys. That's true Tyler - I imagine a perspex 'lens mount' piece, with central hole and a stick/pointer glued into it at exact right angles. Fit the gadget into the camera lens mount and look through the perspex.

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25 minutes ago, David Mullen ASC said:

Shoot a framing chart and look at the negative, you will see whether it is centered or not.

Since you are framing through the viewfinder, that will only tell you where the ground glass frameline is positioned relative to the gate aperture. You can roughly check that by inching the mirror in and out of position while looking through the lens port and comparing the reflection of the ground glass frameline in the mirror to the gate behind it.

It won't tell you where the lens mount (optical) centre is, relative to the gate aperture. If the mount is offset from the centre of the gate aperture and the lens vignettes you might see more vignette on one side, or if it has distortion you might see more of that on one side, but it's not an accurate gauge. 

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If you center the crosshairs in the viewfinder and zoom in and out with a zoom lens, you’d find out how the lens mount is centered.

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