| |
It seems necessary
to define the term ‘professional’ with regards
to the kind of cameras we will be testing in this article.
Professional video products achieve this status by adhering
to a series of conditions regarding quality and versatility,
conditions which are the result of years of study of those
professionals who dedicate themselves to use, experiment with
and improve these cameras.
DoP’s, colour-graders, film colorists, engineers, postproduction
artists, etc. are the people who should decide whether a product
is really a professional tool or if it is just a marketing
strategy by manufacturers to attract the prosumer market,
without reaching sufficient quality standards. As professionals
it is our obligation to be honest about a product’s
real capabilities. Otherwise we run the risk of lowering our
standards so much that any image will be good enough as long
as it can be seen, reducing costs in such a way that considerations
such as professionality, craft and quality will be secondary.
It could be easy to be swayed by manufacturers marketing machinery
but we should ask ourselves whether the definition offered
by a 1080i HDV camera is enough to consider it a professional
piece of equipment or even if it has enough quality to be
considered High Definition. To decide whether a camera deserves
the tag of ‘professional’, it has to be measured
against the standards valued by the kind of professionals
mentioned at the beginning of this analysis. Following is
an analysis of Sony’s HDV HVR Z1E.
Sensitivity:
On an 18% grey card we have seen that the camera's
sensitivity on automatic is of 125 Asa, showing a value on
the wave monitor of 55%, a rather high value which does give
a slightly overexposed image, therefore one should underexpose
slightly to achieve a value of 50% or 45%, leaving the camera's
relative sensitivity between 160 and 200 Asa. This aspect
of the camera is surprising, having 2 less F-stops than the
DVX100 and 1 1/3 less than the HDCam f/900, taking into account
the markets it is attempting to target; for domestic use,
where consumers only use available lighting, it will offer
very low levels of lighting. For professionals it is
also clearly inadequate; not good enough work with available
light in interiors, requiring artificial lighting and therefore
more time during shooting.
Latitude / contrast:
The camera offers the typical latitude values for video, that
is, very low, around 5 F-stops (a contrast ratio of 32:1),
2 stops over the median grey and 3 stops under, taking into
account that loss of detail in high lights is already considerable
over 1, being specially noticeable when one views the recorded
footage.
Compare this latitude with that of the F/900/3 with more than
8 F-stops in aperture latitude ( a contrast ratio of 500:1)
It should be noted that what we see on the screen or the monitor
is not what the camera is recording, since that image is compressed
in a 47:1 ratio through the MPEG-2 system.
The compression system affects specially colour and detail.
MPEG-2 compresses the image by making the camera capture a
full frame out of every fifteen; the frames in between are
put together discarding the peripheral information and unifiying
the values which are similar or repeated. This compression
is very effective but it involves a significant loss of detail
and sharpness specially if there is camera movement. A Standard
Mpeg sequence is composed by I-frames, P-frames and B-frames:
I-Frames: Intra-frames are frames that contain all possible
video information
P-Frames : Predictive frames are created with the precedent
I or P frames
P frames are more compressed than I-frames and provide a reference
to calculate B-frames
B-Frames :Bi-directional frames use the precedent and the
following frames as reference to calculate the compression
of the information on the frame.
In this image we can confirm the camera’s
low latitude. The skin tones have disappeared, in the face
as well as on the arms.
Its worth noting that whenever a frame drops on a fifteen-frame
MPEG sequence, the whole sequence will be affected, meaning
half a second of footage can be corrupted, making a shot useless.
The camera offers in its menu two alternative gamma curves
to the preset curve called Cinematone 1 and 2.

As we can see in the wave monitor these
curves 'collapse" the blacks giving more contrasted images
and with less detail in the shadows. The intermediate tones
are also darkened and need to be colour-graded during post-production.
The recovery of detail in the highlights is virtually unnoticeable
(it barely reaches 1/2 stop)
Resolution / sharpness
The interlaced system offers a far better resolution than
any MiniDV on the market. In the cards we can see how the
resolution offered by the interlaced system is similar to
that of the HDCAM.
HDV resolution card
HDcam resolution card
In the zoomed image we can see how the HDcam has slightly
more resolution. We can also see how the quality of the HDV
camera is far above that of the DVX100 miniDV

The camera offers the possibility of shooting in cinema mode
with the cineframe function. Its worth noting that this mode
does not record with progressive scan; instead the camera
eliminates a field in the image and uses a copy from the following
frame. This implies reducing by half the resolution of interlaced
mode recording, which results in loss of information specially
in vertical resolution and diagonal lines may appear, creating
a see-saw effect. It goes without saying that the quality
this offers is in a different league to that of the real progressive
scan offered by professional HD systems. It is also surprising
to see that this camera does not take into account the needs
of professionals, who would prefer progressive scan systems,
and offers the poorer interlaced system instead.
This is an enlarged view of some columns
in a panoramic shot. We can notice the interlaced effect compared
with the cineframe mode, in which we can see the loss of definition
and the effects of compression. Chromatic aberrations are
present in both of these systems.
Colour reproduction
In this department the camera proves to be a completely inadequate.
The sampling format is 4:2:0 which means that for every four
times that luminance gets registered the red component and
blue dominance are registered alternately red twice, causing
a significant loss of colour tones. Combined with the Mpeg
compression, where similar colours tend to blend (see the
following still life images and the cards), the colour reproduction
ends up being poor, with shrill colours and few tone contrasts.
In the zoomed image we can see the effects of compression,
specially in the magenta/cyan stripes, we can also see the
black edge in areas of high contrast to simulate better sharpness.
The camera does allow for some colour adjustments but these
are clearly insufficient, basically offering the possibility
of adding colour dominances to the image (warmer / colder)
and effects such as preserving a single colour of an image
and turning the others into B&W. for example.

In this comparison we can see HDV's
lower latitude, lower level of detail in the blacks and harsher
whites. We can also see the loss of colour detail in yellows
and greens. The area with the carrots, apples and eggplant
we can see the superior colour tones of HDcam whereas in the
HDV image they tend to merge into a similar tone.
In the Macbeth card as well as with
the bars we can see the tendency of yellow towards red and
Magenta. Cyan also tends towards blue tones.
The lens body (the lens and the prism).
The lens is a Vario-Sonnar® T* High Definition Carl Zeiss
lens with a 12x optical zoom T 1.6-2.8 (4.5 - 54mm)
We ascertained the total absence of vignette halo, maintaining
a uniform luminosity over the whole surface of the image on
a wide angle as well as on tele. Notice the barrel distortion
and the lateral chromatic aberrations that manifest themselves
in the typical colour stripes on edges with very high contrast.
We have also seen how it produces a noticeable flare in high-lights.
Barrel distortion at the widest angle
The camera works with native 16:9 and three CCD, we have seen
how when confronted with intense lights we can see the typical
vertical smear line
Viewfinder / LCD Screen:
They are both excellent as far as sharpness and resolution
goes far better than their competition in the miniDV market
but it was very disappointing to find that both the screen
and the viewfinder do not show a full image, cutting the image
around the edges, which can ruin a carefully framed composition.
The red box is the image shown in the
viewfinder. The remaining part of the image is not shown.
Postproduction:
There is very little that can be done in postproduction with
such a compressed image. We saw when working with Mistika
that the colour correction is very small due to the little
information available and very soon the image is BROKEN UP
with ARTIFACTS. Given that its an 8bit image and that it’s
compression is very high it is very hard to manipulate it.

We can see how a slight adjustemnt of
the contrast causes a loss of colour to the sky in the image
Conclusions:
In my opinion this camera belongs to the high quality pro-sumer
camera and can be a useful tool for those projects which do
not require a high standard in terms of image quality, specially
of colour and in low- light situations. This camera is still
far from Hdcam or any other professional HD format and therefore
cannot substitute these in any case, which does not mean to
say that it should not be used if a project demands the kind
of image quality it can offer. It is not particularly suited
for either documentary work, due to its low sensitivity and
latitude and poor chromatic reproduction, or for fiction,
given that it does not offer a real progressive scan.
Characteristics:
Capture resolution: the CCD captures at 960x1080, which is
transformed to 1440x1080
Output resolution: 1440x1080 is the resolution at which the
footage is recorded to tape, when played back the resolution
is converted to 1920x1080
Colour depth: 8 bit
Sampling format: 4:2:0
Compression range: 25 Mbits/sec = 3.125 MB/sec, around 47:1
Technical info:
Sony HVR Z1E HDV camera.
Wave Monitor / Vectoscope AstroLCD
Sony HD Monitor
ESSER TEST CHARTS TE 105 TE 125 TE 166 TE 222 TE 223 TE 106
(Some cards are transparencies lit by an LV5 spherical format)
The still life images were shot at the Parque del Retiro in
Madrid
The tests were done in the test lab at INFOTV.
The postproduction was done on MístiKa with the help
of SGO. The HDV footage was captured on Premier using Firewire.
Detailed specifications for this camera can be found in bssc.sel.sony.com
|