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(pag 48)
In these tests we have tried to determine the quality
of the Angeniux Zoom for its use in electronic cinematography,
comparing it with the ENG type HD Canon Zoom to make
the results clearer. The Angenieux Optimo Zoom was used
during practically the whole shoot of La Flaqueza del
Bolchevique produced by Rioja Audiovisual and directed
by Manuel Martín Cuenca.
The shots of the faces were taken on HDCAM to be later
studied on a high resolution monitor. The stills that
appear are copies of the originals, limited by their
CMYK processing and the different resolutions.
Technical information
Sony F-900 camera, all the parametres set to preset
Angeniux Optimo Zoom, 12x9.7 HD
Canon HDHJ18x7.8 Zoom
Wave monitor/vectorscope AstroLC
ESSER TEST CHARTS TE 125 TE 166 TE 222 TE 223 TE 106
( some cards are transparencies lit with a spherical
holder LV5).
The cards we used for this test are resolution cards,
grey and coloured for HD.
The tests are done with the support of Info TV, ImagenLIne
and Molinare.
The shots were taken with Arrilaser on Kodak Premier
positive
Homogeneous Luminosity
The first step was to check the luminous uniformity
of the lens across the whole focal plain. We did this
with different focal lengths as well as three different
exposures over a homogeneously lit white surface. With
the Optimo Angenieux zoom 12x9.7 HD we can see that
the loss of luminosity around the edges is hardly noticeable,
Angenieux Zoom Optimo 12x9.7HD
Shortest focal length 9.7mm / Mid-wide angle12mm / Medium
lens 40mm / Longest focal length 116mm
whereas the Canon HDHJ18x7.8 zoom does show a visible
loss of luminosity, specially with the longer focal
lengths with the same exposure.
Canon HDHJ18x7.8
Zoom
Shortest focal length 9.7mm /
Mid-wide angle12mm / Medium lens 40mm / Longest focal
length 116mm
(Pag.49)
At an exposure of 5.6 the response of the Optimo zoom
is completely homogenous with the different focal lengths
Angenieux Zoom Optimo 12x9.7HD
Shortest focal length 9.7mm /
Mid-wide angle12mm / Medium lens 40mm / Longest focal
length 116mm
As we can see, the Canon zoom continues losing luminosity
around the edges with the longer focal lengths.
Canon HDHJ Zoom 18x7.8
Shortest focal length 9.7mm /
Mid-wide angle12mm / Medium lens 40mm / Longest focal
length 116mm
The response of the Optimo zoom at the largest exposure
(F:1.6) was quite homogeneous up to relatively long
focal lengths, however the luminosity around the edges
dropped slightly at the largest focal length.
Shortest focal length 9.7mm /
Mid-wide angle12mm / Medium lens 40mm / Longest focal
length 116mm
(Pag 50)
Lens luminosity
On a grey 18% Kodak card homogeneously lit we observed
that the Angenieux zoom was up to half an F-stop more
luminous than the Canon zoom.
Sharpness
We then tested both lenses’ sharpness, at the
centre of the image as well as the edges. At the centre
of the image *
(ej.6). we see how the Optimo zoom offers a greater
sharpness
*
(ej.6).
This difference in sharpness was even more apparent
along the edges *
(ej.7).
*
(ej.7).
(pag 51)
Resolution
As we can see in*
(ej.8) the difference in resolution between the two
zooms is quite noticeable. Its clear that the Optimo
zoom has a greater resolution, essential quality for
images destined for cinematic projection. Although we
could not obtain the MTF cards for either zooms its
clear from our observations in the HD monitors that
the Canon zoom, just like most zooms conceived for ENG
projects in HD, offers a greater contrast
at the expense of resolution, whereas other zooms like
the Angenieux, created for projections on a cinema screen,
need a greater resolution, which comes at the cost of
reduced contrast.
*
(ej.8)
We have found that the Angenieux zoom maintains the
sharpness and resolution at different focal lengths
and exposures.
Colour
In the HD colour resolution cards *
(ej.9), we again see the loss of sharpness and luminosity
with the Canon zoom, and how the Angenieux maintains
them. The resolution in the centre of the image is good
with both zooms.
*
(ej.9)
The Angenieux zoom responds correctly to standard colours,
although the image as a whole is slightly warmer ( yellower
) than the image obtained with the Canon zoom. The tendency
we observed of the magenta towards the red was also
present with the Canon zoom. We are not sure of why
this is caused, we think that it might be caused by
the card itself or the way that the camera treats this
colour.
*
(ej.11) was projected on a cinema screen. We can see
the warm tone of the visuals, as well as the excellent
resolution, and the soft contrast without losing sharpness.
Skin tones are ‘pleasant’ with a good level
of detail. We also observed that in exteriors skin tones
were not as cold with the Canon zoom, although when
lit with tungsten skin tones became excessively warm.
As always, beyond technical considerations, personal
taste comes into play when choosing which equipment
to use. Personally, I favour soft lenses, which reproduce
shades in transitions from light to shadow.
*
(ej.11)
((Pag 52)
Contrast
The response in the grey scale is homogeneous, correctly
representing the scale and the values of each grey.
Geometry
We have also observed a noticeable barrel distortion
with the longest lens. We can observe the distortion
of the horizontal lines and the circles towards the
edges of the frame.
During the shoot
With the fill lights the zoom has a fantastic behaviour,
with little flare, maintaining soft outlines without
losing sharpness ( pool and office images ).
It was very important to have a lens that maintained
a constant luminosity at different exposures and with
different focal lengths, given that we wanted to shoot
the film without using too much lighting equipment and
the smallest depth of field possible without losing
resolution and contrast, capturing all the details equally
well in shadow as well as in highlights.
Furthermore, the Optimo zoom hardly “breathes”,
not varying in framing when changing the focus.
Focus pullers found problems if they had to change the
focus in a small movement of the actor, which in the
zoom’s scale was quite large, making it hard to
hit the marks.
The accessories to the zoom were all from Arri: parasol
6x6, focus controls, remotes, etc.
Conclusions
From the tests and the experience on the shoot we conclude
the following:
1- Excellent luminous uniformity with all the different
focal lengths and exposures. No notorious spherical
anomalies, such as vignette halo or the like. Only at
the maximum exposure (F-stop 1.6) and with very large
focal lengths there was a slight increase in such anomalies
(Pag 53)
2- Very high resolution, even above that of the camera.
No problems of astigmatism.
3- Excellent RGB resolution although with the warm tones
characteristic of the Angenieux zooms, with very minimal
chromatic anomalies, both axial and transversally, although
these anomalies are more notorious with strong backlights.
4- High sharpness with moderate contrast and little
flare.
5- Excessive barrel distortion wide angles.
6- Excellent field curve correction.
7- It’s a large and heavy zoom which requires
good support and manual hot head or fluid head
Due to the zoom’s size we used the Digiprime lens
by Zeiss, for the hand-held shots and the shots inside
cars. In the next article we will approach these lenses
using test cards and images from the film. The quality
of this zoom justifies its considerable price, although
its use is restricted to films and projects which demand
images of a superior quality for either digital or analogue
projection and viewing on HD screens.
Characteristics of the Angenieux HD Optimo Zoom
Formato: 2/3 (16/9 ratio )
Zoom range: 12x
Focal length: 9.7mm to 116mm
Exposure: F/1.6 – F/16
Back focus EN EL AIRE(????): 42mm
Minimum distance to MD: 0.80 mm ( from the frontal element)
Minimum Area to MD: 54.6 x 72.1 mm
Horizontal coverage angle: 52.7º - 4.7º
Zoom length: 465mm
Weight: 11kg.
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