The Look of the Primo 70 Series of Lenses

The “Look”
The “Look” 1 of 3 / 2015
CONTENTS
SPECS
PRIMO 70 - IMAGE QUALITIES
A Taste of 70
Natural Sharpness
Pristine Image
Panavision Look
Out of Focus Quality
PRIMO 70 - TECHNICAL DESIGN
Technically Superior
Designed for Digital
Aspheric lens elements
Floating Focus
Short Flange Depth
Compact & Light
Fast & Consistent T-Stops
CAMERAS COMPATIBLE WITH PRIMO 70S
CAMERA MODIFICATION: LENS MOUNT
CAMERA MODIFICATION: ADDING A GLASS PLUG
THE WIDE ANGLE ISSUE
APPENDIX: 70MM GLASS GLUG FOR PROJECTION
The “Look” 1 of 3 / 2015
SPECS
Panavision Primo 70 Series
Focal Length
T-Stop
Close Focus
Primes
4P24*
24
T2
12”
.30m
4P27
27
T2
14”
.36m
4P35
35
T2
14”
.36m
4P40
40
T2
14”
.36m
4P50
50
T2
16”
.41m
4P65
65
T2
20”
.51m
4P80
80
T2
24”
.61m
4P100
100
T2
30”
.76m
4P125
125
T2
36”
.91m
4P150
150
T2
48”
1.2m
4P200
200
T2.8
48”
1.2m
4P250
250
T2.8
48”
1.2m
Zooms
4PZW
28-80
T3
33”
8.4m
4PZM
70-185
T3.5
60”
1.5m
4PZT
200-400
T4.5
78”
1.9m
*4P24 in prototype stage, available early 2015
All front diameters: 4.44” / 112/8mm (except 4PZT which is 4.98” / 126.5mm)
The “Look” 1 of 3 / 2015
Page 3
PRIMO 70 - IMAGE QUALITIES
Cinematography is a technological art, and the description of Primo 70s
necessarily combines subjective characteristics that attempt to describe
the look and feel of the image with objective characteristics that can be
measured and analyzed.
Let’s start with aesthetic image qualities a cinematographer might notice at first:
A TASTE OF 70
While the Primo 70s are designed for 70mm image size, their quality is quite
evident with the smaller Super 35 formats of the Arri Alexa, Sony F55 and
Phantom 4K Flex, and with intermediate formats like the Red Dragon 6K.
Although the Primo 70s offer optical qualities that go far beyond the resolution
of these sensors, these lenses can givefilmmakers “a taste of 70” with
intermediate formats. This taste of 70 is also linked to angle of view and
perspective, and we return to this theme in detail at the end of the third paper.
NATURAL SHARPNESS
The Primo 70s are designed for the very demanding high-resolution
requirements of large sensors. Many Cinematographers are wary of “too much
sharpness”, especially on actors’ faces, but after testing the lenses, they may
discover the Primo 70s offer an optical clarity that is neither harsh nor “clinical”.
The optical fidelity of the Primo 70s is created by contrast and definition from
low, medium and high frequency details in the image.
PRISTINE IMAGE
The Primo 70s offer a clean image without many of the optical aberrations that
other lenses have. There is very little color fringing, coma tails, or distortion.
The edges are not very different from the center. This lack of aberrations make
the image easier on the eye, and feels more natural.
The “Look” 1 of 3 / 2015
Page 4
One cinematographer referred to this effect as a “no stress image”. The clean
image of the Primo 70s can also allow cinematographers to dig into the shadows
and pick up details that might be lost in aberrations with other lenses.
PANAVISION LOOK
The 35mm Primos revolutionized cinema optics in the 1990s, by offering low
veiling glare, uniformly matched lenses, faithful color reproduction and sharp
images with a gentle focus fall-off. The Primo 70s continue this tradition of
innovation and quality for large sensors with state of the art optical materials and
designs. They have very few of the chromatic aberrations that can color a lens,
and combine both sharpness and roundness.
OUT OF FOCUS QUALITY
For Panavision lens designers, the out of focus image is as important as the
focused one. While the Primo 70s are undeniably sharp, the fall-off from focus
is gentle and smooth, with an organic quality to it. Out of focus highlights of the
Primo 70s remain round, unlike the “cat-eye bokehs” of other lenses, which
vignette the pupil.
The “Look” 1 of 3 / 2015
Page 5
PRIMO 70 - TECHNICAL DESIGN
The aesthetic qualities of the lenses listed earlier result from choices in the design
and construction of the Primo 70s.
Here are some key technical design features.
TECHNICALLY SUPERIOR
The Primo 70 Series lenses are designed to have better technical performance
and higher quality than any other existing motion picture lenses, in terms of
resolution, colorimetry and illumination across the entire frame.
The Primo 70s MTF numbers for high frequency detail are unequaled, both in the
center and at the edges of the frame. But even more important, the large area
under the Primo 70 MTF curves denotes a natural sharpness that includes the full
range of high and low frequency components.
MTF is not just about the number
measured at a high frequency. Perceived
sharpness is a function of the area
(in beige) underneath the entire MTF curve
(see Otto Schade)>
The shape of the “belly” underneath the
MTF curve is far more important than the
measurement of a single point.
The “Look” 1 of 3 / 2015
Page 6
DESIGNED FOR DIGITAL
The Primo 70s are designed for digital. They won’t fit on film cameras: because
of theirshort Flange Depth, they would bump into the shutter. Their design takes
into account the low pass and infrared cut-off filters in digital cameras.
These filters can diminish performance on other lenses, notably:
• On other lenses creating softness on the image edges due to coma and
astigmatism,(especially with short focal lengths and apertures wider than T2.8)
• Creating over-correction in the image center, adding spherical aberrations on
axis(on all focal lengths)
THE OPTICAL PATH
The optical path for digital cameras has additional elements not present in film
cameras. The Primo 70s are designed for an extra 7mm of glass behind the lens
of a digital camera to account for:
• Infrared cut-off filter
• Optical low-pass filter
• Sensor cover
The “Look” 1 of 3 / 2015
Page 7
ASPHERIC LENS ELEMENTS
Like the Zeiss Master Primes, Leicas and other contemporary lenses, the Primo
70s include aspheric elements. Unlike spherical elements, the contour of these
elementschanges, and is different for light rays on the edges than for center rays.
A singleaspheric element can correct errors that would take several spherical
elements to correct.
This is one reason the Primo 70s are lighter than 35mm Primos.
ANOMALOUS DISPERSION GLASS
The Primo 70 design includes elements with anomalous dispersion, which
have different refraction characteristics than normal glass. This allows for
finer correction of chromatic aberrations.
INTERNAL FOCUS
In a traditional lens like the 35mm Primo, the entire lens head moves with focus.
This means that the lens is optimized for a certain distance, with a slight
reduction in performance at other distances, and in particular at close focus.
The Primo 70 floating focus elements allow for very good performance at all
distances, including remarkable performance at close focus. In addition, the
lenses act like very “weak zooms” that change the focal length just enough
to eliminate breathing (framing change) due to focus change.
SHORT FLANGE DEPTH
The Flange Depth is the distance between the lens mount and the sensor.
Because the Primo 70s are designed for digital cameras, they can utilize a short
flange depth, and are “closer” to the imaging sensor than traditional motion
picture lenses.
The Primo 70 flange distance is a nominal 40mm to the sensor.
By comparison, the 35mm Panavision flange depth is 57.15mm and the PL
flange distance is 52mm.
The “Look” 1 of 3 / 2015
Page 8
Traditional PV and PL mounted lenses include a retro-focus design to enable
the lens to back away from the spinning mirrors of film cameras. The Primo 70
lenses do not face this restriction and can have larger diameter elements closer to
the image plane, improving performance.
The short flange depth opened up new approaches to Panavision lens designers.
The Primo 70s design does not require as much retro-focusing, which makes
for more efficient designs, and more compact lenses.
COMPACT & LIGHT
The Primo lenss are designed to be practical on the film set. The use of aspheric
elements allows for a 70mm lens to be the same size as a Primo 35mm,
but lighter.
FAST & CONSISTENT T-STOPS
The Primes from 24mm to 100mm open to a fast T2 stop. The 200 and 250mm
are T2.8, while the two zooms open up to T3.5 and T4.5.
The “Look” 1 of 3 / 2015
Page 9
COMPATIBLE CAMERAS
Although the Primo 70s are designed for the 70mm format,
they are also compatible with some digital cameras with smaller sensors.
To date Panavision engineers have adapted the Primo 70s to 5 cameras
• Arri Alexa (recommended for Open Gate)
• Phantom Flex4K
• Red Dragon (recommended for 6K mode)
• Sony F55
• Panasonic Varicam 35 (4K)
• Phantom 65
Note that the Sony F65 is not compatible because of its mechanical shutter.
This is not a definitive list. Panavision continues to look at adapting other
cameras to accept the Primo 70s.
The cameras above need 2 modifications before the Primo 70s can be used:
• Lens mount change
• Glass plug Insertion
Primo 70 lens mounted on a Red Dragon camera
The “Look” 1 of 3 / 2015
Page 10
LENS MOUNT MODIFICATION
To use the Primo 70s with a digital camera like the Dragon, Panavision changes
its lens mount to a PV 70mm mount. As noted above, the PV 70mm lens mount
is designed for a 40mm Focal Flange Depth, shorter than the flange for standard
PV and PL mounts.
PV 70mm mount
PV 35mm to PV 70mm adaptor
Panavision has developed a PV 35 to PV 70 adaptor that will allow you to use
35mm lenses with PV mounts, but this may raise two issues:
• The lens will not match the quality of the Primo 70s.
• The lens characteristics may be altered by the Glass Plug inserted into
the camera.
The “Look” 1 of 3 / 2015
Page 11
ADDING A GLASS PLUG
As noted above, digital cameras have an infrared (IR) cut-off filter, an optical
low-pass filter (OLPF) and a cover in front of the sensor. The total thickness of
these behind-the-lens elements varies from camera to camera, and has an effect
on the optical path.
The Primo 70s are optimized for a 7mm thickness of the glass components in
a digital camera. When the lenses are mounted on another camera, we may
need an additional Glass Plug to obtain an optical path behind the lens equivalent
to 7mm, For example, the Red Dragon has roughly 3mm of glass in front of its
sensor, so Panavision inserts a 4mm glass plug to get to 7mm.
4mm Glass Plug
Dragon Sensor
The addition of a Glass Plug into a digital camera is not always straightforward,
and Panavision engineers are working closely with other camera manufacturers
to arrive at the best optical and mechanical solutions.
Also, if the filmmakers use lenses other than the Primo 70s on a modified
camera, the Glass Plug may alter the optical characteristics of these lenses,
notably in the corners.
The “Look” 1 of 3 / 2015
Page 12
THE WIDE ANGLE ISSUE
-- See white paper 2 in this series for an explanation of Crop Factors & Fields of View -The Primo 70s are designed for a 70mm sensor, which has a Crop Factor of
about 2. So the widest lens in the Primo 70 series, the 24mm, has roughly the
same Field Of View as a 12mm in Super 35, which is plenty wide.
However when using the Primo 70s with smaller sensors, the 24mm may not be
wide enough. When shooting 2:39, the 24mm has the same Field Of View as:
• 19mm on a Dragon 6k
• 21mm on an Alexa Open Gate.
• 24mm on a Sony F55, the same as Super 35.
This may not be a wide enough angle for many filmmakers, who will expect to
see lenses with Fields Of View roughly equivalent to that of a 14mm in Super 35.
Filmmakers are used to having these wider focal lengths in their package, and
they’re especially useful in interiors, when the camera is up against a wall.
If we apply the crop factors for these smaller sensors this implies that we are
missing wide lenses with focal lengths around 18 millimeters. Panavision is
working on manufacturing some as soon as possible.
In the meantime, Panavision technicians are assisting filmmakers in selecting
and adapting existing lenses to cover the wide end. The difficulty is to find lenses
that can intercut with the Primo 70s. The wide-angle lens selection is an ongoing
process.
The “Look” 1 of 3 / 2015
Page 13
APPENDIX. 70mm PROPRIETARY GLASS PLUG FOR PANAVISION PROJECTION
Hooked 7mm glass “plug” inserted behind Primo 70 lens on PV projector system
The “Look” 1 of 3 / 2015
Page 14
Acknowledgements
A white paper by Benjamin B
Thanks to Dan Sasaki for defining key concepts for this paper
Special thanks to Jim Budd and Andrew Young
Thanks also to:
Dominick Aiello, Judy Doherty, Alan Gilson, Jamey Jamison, Dave Kenig, Lee
Mackey, Christian Malone, Laurence Nunn, Jim Roudebush, Haluki Sadahiro, Tony
Samuels, Peter Swarbrick, Charlie Todman, Sharon Walker
The “Look” 1 of 3 / 2015
Page 15
Download PDF