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JVC® DLA-RS2U 1080p D-ILA® Front Projector
THE ROGERS REPORT .
adjustments, I was able to calibrate the gray scale within 1 dE of D65
from 5 to 100 IRE.
Brightness And Contrast Ratio
I made light output and contrast measurements using the HDMI
input with the gray scale calibrated to D65, as indicated above. I
took initial measurements at about 12.8 feet from my new 87-inch
wide, 16:9 Stewart Filmscreen StudioTek G3 screen. In the High
Lamp mode, the projector produced 603 lumens, which is equivalent
to 26.4 fL from the 1.3 gain screen, and an extraordinary full-field (on-
off) contrast ratio of 25,200:1. The projector produced about 502
lumens in the Normal lamp mode from the same throw distance.
With the exception of expensive “constant aperture” zoom lenses,
the variable f-number of a zoom lens significantly changes the bright-
ness and contrast ratio as the throw ratio is changed. Brightness is
maximized, and the contrast ratio is minimized at the short throw end
of the zoom range, and conversely brightness decreases, and the
contrast ratio increases toward the long throw end of the range.
At the zoom lens’s minimum throw ratio, the RS2 produced 661
lumens in High lamp mode and a still extraordinary 19,200:1 full-field
contrast ratio. At the maximum throw ratio it produced 473 lumens
and an astonishing 30,900:1 contrast ratio. This is an incredible
achievement. Not only have the contrast ratios been dramatically
improved to unprecedented new heights for a lamp-based projector,
the light output is also impressive. The best DLP projector contrast
ratio I’ve measured was 7260:1 at 402 lumens, or 7920:1 at 330
lumens.
Another important performance parameter is intra-image contrast,
which describes the ability to differentiate contrast differences when
there are bright areas near darker areas in the same image. The
intra-image contrast ratio is much lower than the full-field contrast
ratio because light from bright areas will be scattered over the image,
obscuring darker areas. The light scattering occurs within the lens
and the optical system of the projector, but it may also occur within
your theatre as light reflects around the room and back onto the
screen.
My modified “ANSI” contrast ratio is a figure-of-merit to character-
ize intra-image contrast performance. It is designed to minimize the
influence of room reflections and other variables that would affect
measurement accuracy. The modified “ANSI” (m-ANSI) contrast ratio
measured 310:1. That is good performance, but virtually unchanged
from the RS1, and considerably less than the best 1080p DLP projectors.
Gamma
The RS2 has a large set of new, highly flexible gamma features. It
has four preset gamma modes (Normal, Theater1, Theater2,
Dynamic) and a Custom mode. The new Custom mode provides
additional preset gamma values from 1.8 to 2.6 in 0.1 increments.
Those gamma values can be used without modification, or a custom
curve can be created using one of those values as a reference
gamma curve. The Custom Gamma Adjust function provides an on-
screen graph to modify the reference gamma curve at 11 points from
5 to 95 percent signal levels. The R, G, B signal components can be
adjusted individually or simultaneously. The former can be used to
optimize the gray scale tracking, and the latter used to produce an
overall custom gamma curve for the projector.
The accompanying charts show the measured results for most of
the predefined gamma curves. The extraordinary full-field contrast
ratio allows one of the higher gamma values to be used without
obscuring near-black shadow detail. I used the 2.4 and 2.5 gamma
curves, which produced images that are more CRT-like than other
lamp-based projectors. The higher gamma values substantially
increase the perception of image depth in most films. That is also
why CRT projectors produce satisfactory image depth, despite their
very low ANSI contrast ratios.
White Field Uniformity
Brightness uniformity on a white field test pattern varied by only 4
percent at the sides and 3 percent at the top and bottom of the
screen. Color uniformity varied by only 3 dE at the top and bottom of
the screen, and by just 4 dE at the sides of the screen. The color
variations were smoothly distributed across the screen and not
noticeable in any films.
“Black field” color and brightness uniformity was visually insignifi-
cant and not an issue while viewing films. I could just barely perceive
a slight brightness elevation in the corners if I allowed my eyes a
minute or so to adapt to a black test field. That was a big improve-
ment over the RS1 that I previously reviewed, which displayed annoy-
ing bright corners during fade-to-black frames. There was some
minor light spill above and below the screen, which is easily dealt
with by placing dark masking around the screen.
Lens Quality And Convergence
All three-panel projectors are susceptible to convergence errors
from panel misalignment. The RS2 includes adjustments to horizon-
tally and vertically align its red, green, and blue images, but the
adjustments are limited to full-pixel increments and affect the entire
image. Panel mounting tolerances in multiple axes can result in sub-
pixel misconvergence that isn’t uniform across the screen, so some
residual misalignment can remain. Misconvergence can produce
color fringing on bright edges, and reduce sharpness and resolution.
Widescreen Review • Issue 129 • March 2008
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GAMMA MODES
#129 JVC REPRINT:Layout 1 2/7/08 1:54 PM Page 5