Ground Glass

November 5, 2004

So the viewfinder won't be far out then, can it be adjusted to align with what your really shooting?

Phil Rhodes · November 6, 2004

Hi,

Drastically? Well, that would depend how far you zoom in, fairly obviously. Bear in mind also that some telecines and scanners can optically zoom in, ergo you don't lose resolution digitally, although of course you're still reducing the negative area and increasing grain and any optical aberration due to the camera lens.

Yes, the position of the groundglass can usually be adjusted.

Phil

GWilliamPatrickB · November 7, 2004

It's mainly because 35mm 2-perf Full Aperture is 2.66 : 1, so there's no need to use anything wider than Academy.

<{POST_SNAPBACK}>

This is about ground glasses but a little off topic. I just had a GG sent to me by Arri. It was the wrong one! It is a 185 / 137. Now, I have known that 137 was out there but in all my years I have never used one or knew what I would want one for. After going through all my CSC manuals, I still cant find what reason it has to exist. All I get is the acnowlegment that it exists. I want to know WHY. And why on my 185 GG.

It is the same width and is higher and lower / equally top and bottom.

GWPB

Edited November 7, 2004 by GWPB

David Mullen ASC · November 7, 2004

Academy is 1.37 : 1. In a pinch, it can be used as a 4x3 TV framelines (1.33 : 1) if you keep overscan in mind plus a little more trimming on the sides.

GWilliamPatrickB · November 7, 2004

Academy is 1.37 : 1. In a pinch, it can be used as a 4x3 TV framelines (1.33 : 1) if you keep overscan in mind plus a little more trimming on the sides.

<{POST_SNAPBACK}>

Thanks, but why wouldnt it just be called Academy to end confusion?

GWPB

Christian Appelt · November 7, 2004

David Mullen wrote

Historically, the forerunner to Super-35 was SuperScope, which involved extracting a 2:1 image from inside Academy and blowing this up to CinemaScope with side mattes to preserve the 2:1 image. This was improved two years later with SuperScope-235, which involved extracting a 2.35: 1 image from inside Full Aperture.

David, is it absolutely sure that the did use the full frame for Superscope-235?

I always assumed it until I read somewhere that the area extracted was even smaller (lower) than with "original" 2:1 Superscope, the only reason for doing so was to compete with the (optical sound) CinemaScope format of then 2.35.

I checked all vintage trade papers and manual I could find, but nowhere a word about using a larger aperture for Superscope-235. Do you have a source where I could find the exact specifications. At www.widescreenmuseum.com I found this illustrations:

SuperScope AWSM

I doubt it is correct because in all publications I know the standard Academy aperture is mentioned and the advantage of using standard lenses and cameras (without recentering lens mounts) is stressed.

Martin Hart writes (referring to projection format):

The need to readjust projector or lens alignment was solved by shifting the frame to use a common centerline with CinemaScope, and finally the system evolved into Superscope 235. Here the extraction area was further cropped down to yield a 2.35:1 aspect ratio and the prints were made using CinemaScope compatible specifications. This further exaggerated the problem of film grain which was considered to be excessive even in the older format.

The American Widescreen Museum has a process demo with film strips examples, but they also show full frame.

Superscope demo

The positive print has the asymmetrical matting that made it necessary to recenter lens mounts on the projectors before screening a Superscope print, but I am somewhat puzzled about what kind of aperture did they really use?

:(

Edited November 7, 2004 by Christian Appelt

David Mullen ASC · November 8, 2004

All I really know about the SuperScope 235 format is off of the BKSTS Widescreen Formats poster. It clearly was hardly used. I wouldn't be surprised that they played around with extracting 2.35 from Academy and then from Full Aperture but hardly anything was shot either way before the whole process was dumped in favor of standard 1.85.

Tony Brown · November 23, 2004

They all look a mess to me :blink:

Is it really beyond your means to buy seperate ground glasses for each format? I shudder to think about the confusion such a ground glass will cause with Directors / Agencies etc.... Its all going to look a bit Mickey Mouse is it not? You'll spend more time sticking bits of tape on monitors than concentrating on the shot.

Laurent Andrieux · November 23, 2004

I would like better draft #2. I defenetly think it's better to center the image. Not only for zooms, but also because the eventual residual aberations would be better distributed (vigneting, aplanetism...) Also you d get a better distribution of the off frame limits (boom are more often on top...)

I agree the best would be to have 2 different ground glasses... )I actually don't remember well how you remove it on this camera)

Another point is that if mixed with other images (A cam...) the guy at the telecine might forget sometime to top align your image and just do the scope format centered as usual...

Edited November 23, 2004 by laurent.a

John Sprung · November 23, 2004

...the guy at the telecine might forget sometime to top align your image and just do the scope format centered as usual...

<{POST_SNAPBACK}>

At least here, a dailies colorist who failed to notice that kind of gross error in headroom for an entire camera roll would soon be seeking some other kind of employment. ;-)

-- J.S.

Nate Yolles · November 24, 2004

It happened that the selling camera house came across a prestine glass with Academy, TV safe and 1.85. So that's what I have and I'm extremely happy with it.

Edited November 24, 2004 by Nate Yolles