The temperature is not terrible, but it could be a bit more linear. If course, the brightest areas are the most noticable and on my unit, they did indeed run a bit to the blue.
Luminance (Gamma)s>
Here is a graph of the luminance output when the projector is in 'Natural 1' mode. It could use a little tweaky-tweak, but looks pretty good.
The projector won't be able to do the deep, deep reds of a 3-chip DLP, but saving $25,000 in the price should make you feel better about that. There is plenty of saturation in the very slighty orange red, though.
I think that the biggest coloring concern is a deep green, which will come out a little on the pale side (towards yellow). The D-ILA has a green that is in the stratosphere due to the Xenon bulb.
I do understnad that some of these issues are not LT150 specific, but DLP specific. LCD projectors should be able to produce a somewhat more saturated green.
Anyway, enjoy the pictures! I probably won't have a chance to make any more for a little while, but I wanted to get these up while I could.
Mark
[This message has been edited by milori (edited 08-17-2001).]
I do understnad that some of these issues are not LT150 specific, but DLP specific.
Could please explain which issues you mean? I thought the color gamut, temperature and gamma were dependant on the lamp, color filters and firmware, not the technology?!?
Is it too early to tell yet if we can look forward to improvement in black level? Is it going to let you manipulate the bias voltage (or is that term used only with DILA)?
Bob
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~ The Sultan of Cheap ~
[This message has been edited by RobertWood (edited 08-17-2001).]
Sorry for the hit-and-run, but I won't have too much more time to spend on this for a little while. Here are the answers to your questions, though.
Arrow,
I am using a pre-release version of Colorfacts for the data.
Huckster,
You're probably right that it could be the bulb technology and not the DLP technology that causes the slightly yellowish greens, but I don't have a Xenon arc lamp DLP (i.e. 3 chip DLP) to compare. I understand that most (all?) single-chip UHP DLPs exhibit similiar characteristics.
Billy,
I haven't done anything more than above ('Natural 1'). Maybe this weekend I can try Natural 2.
Bob,
I just got my LT150 cable yesterday. I don't know anything about if this thing is 'Tweakable'...yet...
It may or may not make much of a difference, but the bulb assembly appears to have a filter on it that reflects purple, while the miiror itself seems to reflect a greenish tinge...
Colorfacts is a general purpose projector profiling package. You can use it on any projector you like and it will find the colour primaries, colour temperature, greyscale linearity, and all sorts of good stuff!
Kam is correct, there is nothing D-ILA specific about Colorfacts.
Apg, Interesting observation! So, do you think that the electronics/wheel put out too much green, and then the optics/filter try to correct for it? I hadn't heard that before, but that would be interesting.
I believe Bias Voltage is specific to DILA, and maybe LCD, because it is voltage which determines the LCD transmissiveness (reflectiveness, in the case of DILA). I know you know DLP uses mirrors, and thus, I don't think this applies to them.
Sorry, Arrow. I should have explained things a bit.
The first graph is the "Temperature Histogram" and displays how the grayscale tracks. Black is on the left, white is on the right, and grayscales are between them.
The goal of that graph is to get a flat line, right where the dotted line is displayed. Small errors are difficult to see by eye. This projector has a temperature that is low in the dark areas, but high in the bright areas.
In a nutshell, that means that darks images are a little too reddish and bright images are a little too bluish.
The second chart is the "Luminance Histogram", and follows the same basic pattern (black on the left, white on the right) except displays output luminance. This is mostly a function of the gamma settings in the projector.
The third chart displays a "gamut" of the colors that the projector can produce. Colors in the triangle are reproducible, and those outside the triangle are not. You can determine how closely a device adheres to standards (like NTSC) and find out where the projector will have difficulty producing accurate coloration (green, on this particular unit).
The best way to learn about this stuff is to read the Colorfacts manual <grin>.
I noticed something odd during the Colour Decoder check with Avia. Running the disc in interlaced mode the colours seemed pretty good. However in progressive mode with the same test - the green colour was about 15% to low.
Perhaps this corrobrates what Mark's tests have shown.
Puzzled as to why green drops in progressive mode though.
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Every man is my superior, in that I may learn from him.
Accordingly this test was done on factory default settings (out of the box) via component inputs. So, one can boost the green a notch or two in the gamma table to compensate? http://www.avsforum.com/ubb/smile.gif
Was this test done with the color wheel white segment disabled? If not, then it probably should be, since the colors should be much better with this white segment disabled.
Mark, I suppose that this lamp on that unit is new, new lamps usually are to much blue, it will be good to do the same test after running the lamp 60 to 100 hours.
it will be good to do the same test after running the lamp 60 to 100 hours.
Great idea, Federico. I will do exactly that. It will be interesting to see how the red burn-off affects the data.
Quote:
One question: when do you think I will have one of this Colorfact on my hands?
Soon. An announcement of general availability should be coming this week.
Noah,
Quote:
What are the temperaures at the low and high IRE's
Good (hidden) suggestion, there. The range should be marked on the graph for gauging relative distances. I'll put it on the list http://www.avsforum.com/ubb/biggrin.gif .
The bottom is 0 degrees and the top is 13000 degrees, so 6500 is right in the middle. Although this appears atrocious at first glance, a lot of devices plot off the chart completely (just a solid line spiked at the 13000 mark).
Quote:
Did you also take a look at the Gamma for Natural 1 versus Natural 2?
Unfortunately, I didn't really try much. I only tried Natural 1, and only with the white section off, and only with all end-user controls at the default.
I just wanted to take a quick look at it. I will do a more extensive study soon.
Looking at your Temperature Histogram, I wonder if tweeking the white balance controls of the LT-150 would yield a flatter line. Given that your LT-150 is more or less the same as mine, would reducing the "Red Bright" and the "Blue Contrast" accomplish this? If so, by how by much? Would I also need to increase the "Red Contrast" to compensate for less overall red loss?
Mark, are these measurements screen dependent? In other words, can the screen cause some additional nonlinearities that are not inherent to the projector itself?
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