To get the best image from modern camcorders, you can't just set
exposure and focus and push the red button. Most camcorders offer you a
degree of control over their sharpness, colorimetry, and tonal scale
rendering, and some provide a staggering set of picture-painting
choices. With judicious use of these controls, you can get crisp,
pleasing images from almost any camera. Conversely, misadjusting them
may make your pictures disappointingly soft or irritatingly edgy; pale
and washed-out or garishly oversaturated; limp and lifeless or harsh and
contrasty with crushed shadows and blasted highlights.
The Panasonic HVX200 offers a high degree of tweakability. It has fixed
gamma presets for News, HD Norm, Low, SD Norm, High, Black Press,
Cinelike D, and Cinelike V. Four color matrices-Normal, Enhanced,
Fluorescent, and Cine-Like-complement the usual saturation, hue, and
color temperature settings. Most gammas let you set low, mid, high, or
auto knees, and you can dial in detail from -7 to +7.
In the "Texas Shoot-Out" (Sept. '06 DV, online at
www.dv.com/features/
features_item.jhtml?category=Archive&articleId=192501232), we shot the Panasonic HVX200
using the Normal color matrix, detail at -7, and Cinelike D gamma.
Although we loved the neutral, natural color of the resulting picture,
we found the highlight handling and apparent sharpness disappointing
compared with some of the other cameras. I vowed to explore the HVX200's
settings in more detail to see if I could get better looking pix out of
it-so here we are.
The IR remote is your friend
I set up a scene containing shadow detail, highlights, and everything in
between. A 1,000-watt Tota-light in a Chimera small-video
softbank located 60 degrees off-axis to the left of the scene provided a
soft key; I used a bare 500-watt Tota nearly 90 degrees to the right for
a raking sidelight. Three 75-watt PAR floods in overhead cans and a
large picture window behind camera right offered some fill. I opened the
door to get some bright 5600K exterior into the scene.
With the camera in 1080i60 mode, I exposed the middle gray in the chart
at 50 percent and measured various scene values with a Spectra Pro
meter. Incident readings outdoors in shade were 2 stops higher; full
sunlight was 4 stops up, referenced to incident readings at my seated
position indoors. Incident light on the grayscale in the cabinet was -2
stops, reflected readings from shadowed areas in the cabinet were -3.5
to -4 stops, and the dark area on the HVX200's lens barrel was -4 stops.
Skin tone read about +1 stop, the wall area was +2, and the splash of
light from the small halogen light topped out at +4 stops.
Lacking anyone foolish enough to model for me during the three hours I
spent running through the camera's settings, I wound up shooting myself,
using the HVX's infrared remote to navigate the menus and to trigger
recording-a great time-saver. I only had to get up to reposition a
tripod to block a specular highlight from sunlight bouncing off a car
window, which caused excessive flare.
I ran through the camera's eight different gamma curves, including News
gamma (which is available only in 60p and 30i frame rates). I left
detail at 0 and knee at auto, but also tried other knees in the HD Norm
and High gamma settings. I tried all four color matrices in HD Norm,
High, Cinelike D, and Cinelike V gammas. I ran through detail settings
from -7 to +7 with HD Norm gamma, low knee, Normal matrix, and also ran
15 combinations of color level and color temperature settings. Sample
frames from all these tests are posted at the end of the article.
I photographed a Stouffer Industries TLF4110, a 41-step transmission
grayscale with 1/3 stop steps (www.stouffer.net). I shot this scale with
all eight gammas, using low knee when possible (the Cinelike gammas
don't allow knee selection) because I'm interested in maximizing usable
dynamic range. I looped the clips on a CRT monitor, both as-is and after
applying a black-stretching gamma adjustment in Final Cut Pro 5, and
counted the number of distinguishable steps in the image to determine
each gamma setting's latitude. I recorded the output of a Magni MM400
rasterizing waveform monitor WFM to make the composite gamma chart shown
here.
Click To Enlarge
Three different gamma settings, and superimposed grayscale curve.
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Finally, I spent half a day looking at skin tone, glass, sunlit and
shadowed foliage, polished metal, hummingbirds, and other varied
subjects on a Panasonic BT-LH1700W HD LCD, while playing with gamma,
knee, and detail settings on the HVX200.
Detail and sharpness
The HVX200 has 960 x 540 CCDs, so its limiting resolution is low; adding
detail enhancement improves the apparent sharpness of the image. In
Texas, we used -7 (detail off) and the image suffered for it. Set detail
to +7, and everything picks up harsh edges. I usually use -2, which
crispens the picture without adding too many objectionable outlines and
halos, but others (for example, DP Chris Oben; see
www.chrisoben.com/hvx200article.htm) opt for higher settings like +2.
Why so different?
While repeatedly going back and forth between settings, I discovered
that the Cinelike gammas have roughly half as much enhancement applied
for any given detail setting as non-Cinelike gammas do. A detail setting
of 0 in Cinelike gammas is roughly the same as -3 in other gammas; +2 in
Cine gammas is like -2 otherwise (hence Chris Oben's +2 in Cinelike D is
about as "sharp" as my -2 in HD Norm); +7 Cine roughly matches 0
non-Cine. I've owned the flippin' camera for several months and never
noticed this until now... is my face red!
In general, I found that -2 (on the non-Cine scale) is a good compromise
between sufficient sharpness and excess edging for many subjects and for
my taste, but the ideal setting is very scene dependent. Contrasty glass
and metal that have specular highlights often looked better between -4
and -6; brightly sunlit scenes improved with a setting of -3 or -4,
whereas similar scenes in the shade might warrant a setting of 0 to +2;
+7 gives you an exaggerated "TV news" look.
Unfortunately, the camera's LCD and EVF aren't useful in picking detail
settings; higher-resolution HD (or SD) monitors are a necessity to see
these subtleties of the signal.
Highlight handling
The HVX's Texas overexposure test, shot in Cinelike D gamma and Normal
color, showed an unpleasant yellow hue in overexposed skin tones. I used
the same method as in the Texas test (neutral gray at 50 percent in
Normal gamma, fix exposure, set shooting gamma, shoot, open 2 stops,
shoot again), varying only the gamma. As luck would have it, Cinelike D
is the worst gamma curve for this case; the non-Cine gammas are all
nicer, and Cinelike V is the best of the bunch, comparable to the JVC
HD100's excellent performance.
Click To Enlarge
Normal exposure and +2 stops in Cinelike D and Cinelike V gammas.
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Gamma and latitude
The HVX's gamma curves offer different looks, but largely capture the same dynamic range, at
least with Low knee. I measured 8 stops for SD Norm, Low, Black Press,
and Cinelike V gamma, and 8-1/3 stops for News, HD Norm, High, and
Cinelike D gamma. With some fairly drastic black stretching in Final Cut
Pro, I could eke out 9-1/3 stops in all gammas, albeit with some fairly
severe noise in the shadows.
Setting a higher knee on gammas that allow it caused the loss of as much
as 1/3 to 1/2 stop in the highlights, but left the highlights less
compressed.
Fortunately, gamma setting changes and highlight handling are visible in
the camera's LCD and EVF, though a properly calibrated monitor still
does a better job of showing you what you've got.
Lessons learned
We always say you should shoot tests to learn how a camera works. I
proved that here: I should have shot these tests before the Texas
Shoot-Out. Had I done so, the Panasonic HVX200 would have turned in a
noticeably nicer performance. Its pictures would have appeared sharper,
and its highlight handling would have been more pleasing.
This exercise demonstrated the importance of a good monitor.
Successfully tweaking the HVX200's detail setting required it, and the
monitor more clearly showed the effects of other settings than did the
camera's LCD and EVF.
Finally, I learned that there are secrets beyond what the manual holds,
and beyond what one might reasonably expect. Even though I've been
shooting with the HVX200 for some time, it still surprised me with the
differing detail levels between cine and non-cine gammas.
You may find that spending a day or two just playing with your camera
may yield similar insights, allowing you to paint more elegant pictures
with your chosen tools.
HVX200 Parameter Settings
The different gamma settings of the HVX200
How the KNEE control affects pictures
Different gammas and how they handle overexposure
The different MATRIX settings
|
Norm Matrix |
Enriched Matrix |
Fluo Matrix |
Cine-like Matrix |
HD
Norm
Gamma |
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High
Gamma |
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Cinelike
D
Gamma |
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Cinelike
V
Gamma |
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The range of COLOR TEMP and CHROMA LEVEL settings
|
Chroma Level -7 |
Chroma Level 0 |
Chroma Level +7 |
Color
Temp
-7 |
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Color
Temp
-4 |
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Color
Temp
0 |
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Color
Temp
+4 |
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Color
Temp
+7 |
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