Confusion regarding full frame, half frame, ect
Posted 05 February 2009 - 02:08 AM
With all the talk of the upcoming "full frame 35mm RED EPIC camera" and everything, and the super35mm sized sensor of the RED ONE, I started doing some research and got confused..
I see there is full frame 35mm, 24x36mm
and then there is half frame, 18 × 24 mm
When researching super 35mm, I realized the height of the film was still only 18mm high and I got confused; I expected it to be 24mm high because thats how high I thought film was supposed to be.
So my question is, which format is more wide used, and what is the difference? are special cameras for half frame and others for full frame? Is this difference in frame size indicated when you buy film stock? Are the number of perfs different
is there a Super Full Frame type of film that offers the height of full frame, yet wider?
I'd appreciate some clarification from the more knowledgeable members here. I'd love to learn.
Posted 05 February 2009 - 02:38 AM
24mmx36mm full frame is the standard 35mm size for stills that your Leica or SLR takes. There is a MP format that uses this frame size and it's called Vistavision. It's mainly defunct, but is still used for some effects work.
All of these can exist on the same film stock. They just orient the picture differently and use different bits of the space between the perfs. Still film uses different perfs than MP film.
Posted 05 February 2009 - 04:38 AM
Can spherical 35mm Cine lenses cover a still Full Frame?
Or are they made to only cover a Cine full frame?
Did vista vision use longer focal lengths? Would it be considered somewhere between 35 and IMAX?
Which frame size is used for Panavision Primo Anamorphics? Super35 or Academy aperature? (assuming academy aperature is 18x24..which i'm sure im wrong)
Posted 05 February 2009 - 10:54 AM
4-perf 35mm Academy is 22mm x 16mm
4-perf 35mm Full Aperture (Silent) is 24.89mm x 18.67mm
4-per 35mm Anamorphic is 22mm x 18.59mm
3-perf 35mm Full Aperture is 24.89mm x 13.87mm
8-perf 35mm (Full Frame / VistaVision) is 37.72mm x 24.92mm
5-perf 65mm is 52.63mm x 23.01mm
15-perf 65mm (IMAX) is 70.41mm x 52.63mm
The RED ONE sensor is 24.4mm x 13.7mm, but that's for 4520 x 2540 -- "4K mode" uses 4096 across, so it is more like 22mm wide.
Lenses made for 35mm cine are designed to cover 4-perf 35mm Full Aperture, which is 24.89mm across. They cover more than that, but generally you can't expect the shorter focal lengths to cover the 37.72mm width of 8-perf 35mm, but some longer lenses might. For example, someone over at RedUser said that his wide-angle Zeiss Master Primes create an image that is 31mm across, so that would be short of covering FF35.
There is a magnification factor of 1.5X to cover the difference between 24mm wide and 36mm wide, so to match field of view, you'd have to use a lens that was 1.5X longer in VistaVision compared to S35.
Primo Anamorphics are designed to cover the 4-perf 35mm anamorphic aperture (22mm wide), but they cover the slightly wider Full Aperture (24mm wide) as well.
Keep in mind that a spherical lens creates a circular image and the camera aperture crops this to a square or rectangle.
Posted 05 February 2009 - 12:42 PM
Just one more question...
If an anamorphic image is captured on a wider format, say super 35, will the de-squeezed projected image be much wider than 2.40:1??
Do anamorphic lenses create a circular image circle as well? Do they have the ability to cover wider formats, creating ultra wide panoramic images?
Posted 05 February 2009 - 12:54 PM
The standard anamorphic lens used mostly commonly today has a 2X squeeze, so the aspect ratio just depends on the shape of the camera gate and the projector gate.
The 4-perf 35mm anamorphic camera aperture is 22mm x 18.59mm (1.18343 : 1), but the projector gate is 20.96mm x 17.53mm (1.19566 : 1).
Once you unsqueeze by 2X, the aspect ratios therefore become 2.36686 : 1 for the camera gate and 2.3913 : 1 for the projected image.
Since 4-perf S35 / Full Aperture is 1.33 : 1 (it's the same as the original Silent Era aperture) therefore the image would be 2.66 : 1 if you used a 2X anamorphic lens on the camera.
In fact, originally that was how CinemaScope was supposed to work -- shoot and project Full Aperture, unsqueeze to 2.66 : 1, and put the soundtrack on a separate interlocked mag, like how Cinerama was projected (which was also a 2.66 : 1 format). But that plan was killed even before the first CinemaScope move was finished. They used a print stock with smaller perfs ("CS" perfs) in order to fit mag stripes on each side of the frame, shaving the width of the projected image down to 2.55 : 1.
Later they dropped that idea and put an optical track on the left side only, just like for all other 35mm prints; this shaved the width of the image to 2.35 : 1 and shifted the optical center over to the right.
Then in the early 1970's, the shaved the top & bottom of the projector gate to hide frameline splices better. This changed the shape from 2.35 to 2.39... : 1, often rounded up to 2.40 : 1.
Posted 09 February 2009 - 11:47 AM