HD80 Calibration and Black Levels
Calibrating
this projector was essential. We were not pleased with the initial measurements
– especially with the high color temperature and excessively blue picture. If
all HD80s behave as this one, you will want to get your projector calibrated by
an ISF professional to get the optimal picture quality from it. After I tweaked
this unit, I was pleased with the performance, but initially there is much to be
desired.
We utilized datacolor’s ColorFacts Professional 6.0 software to calibrate and measure the grayscale response of the HD80. Starting positions were more than slightly off and we wondered if the unit would be able to be brought under control through calibration. For the ‘before’ measurements, Auto Iris was engaged and the settings were configured for best film response in a light-controlled room.
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Before Calibration |
After Calibration |
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You can definitely see the initial color temperature throughout the entire IRE range. I was skeptical if I would be able to fix it completely. |
I guess I should have more confidence in myself as the values came together and we received very favorable results. We did note, that the red curve held its shape, dropping off significantly after 80IRE. This left a rather unnatural cast to any solid white areas on the screen. |
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We have a somewhat S-shaped gamma curve that is not what we want in this projector. |
After measurements had the Auto Iris disengaged and we noticed a marked improvement. |
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Yech – color temp averaged around 8300K – ridiculously high and nowhere near the desired D65. |
After calibration, we scored 6500K +/-100 IRE for most of the practical luminance range. |
As you can see there are issues with the initial calibration of the HD80 and we had to really tweak it out (in the User menu) to get it into shape. If you're an installer, look forward to charging for an ISF calibration after you install this projector – it's all but required for best performance. Some interesting tidbits from my adventures:
My initial measurements were taken with the Color Temp set to 'Warm', the Irisz at Max (16), Cinema Mode, Film Degamma, ImageAI set to 'Off' and Brite and High Altitude modes set to 'Off'. With these settings here are the color temperature measurements:
- Warm = 8300K
- Mid = 9400K
- Cold = 11,400K
Wow, that's one cool projector – but not in the way that you want it to be cool. We proved that calibration can fix this, but Optoma should have better initial measurements on its projectors.
We measured around 21.5fL at 100IRE using our “best guess” Cinema settings. Here' is how the lumens looked through various modes:
- Cinema mode = 21.5fL
- Bright mode = 23fL
- TV mode = 27fL
- sRGB mode = 20fL
Now, Bright mode crept up to 31fL with the lamp's Brite Mode turned on. When I opened up the Iris (to 0) it fairly leaped to 51.5fL. That's bright!
Let's talk Contrast Ratio for a moment. I actually measured 1535:1 in Cinema mode, though this was based on a reported black level of 0.014fL. The Contrast Ratio went up to 1800:1 when I engaged the Auto Iris mode. In Bright mode with AI turned on we saw 2196:1 measured Contrast.
Note: Engaging Image AI (Auto Iris) negates the ability to disengage the Brite Mode lamp option. Image AI requires full lamp power in order to have the range of values it needs to alter the light output. As a necessary result, the fan noise increases. We recommend disabling Image AI and opting for the quieter low lamp mode and setting the Iris to 16 (closed) in light-controlled rooms.
