Posted on March 31, 2018 By Eric Pfoutz
BenQ HT2550 4K UHD Home Theater Projector Review – Calibration Settings: Calibration Presets Notes, Best Mode Calibration, Brightest Mode Calibration & 4K Calibration
Note: The projector had over 45 Hours on the lamp before I calibrated it and took the light measurements. A brand-new lamp will most likely have slightly higher measured lumens.
The HT2550 has 6 modes (Bright, Vivid TV, Cinema, Sport, User 1, User 2. I spent most of my time with Cinema, Vivid TV and User 1 & 2. The projector also includes the ability to create and lock ISF Day & Night modes. All of these modes have the same controls, what sets them apart is how these controls are preset. They all offer 4 color temperature options (Normal, Cool, Warm, Native Bulb), 2-point grayscale adjustments, gamma presets 1.6 – 2.8 and full CMS (color management system). Note: In order to change one of the 4 color temperature presets, you must first turn off Brilliant Color. After you select you preferred color temp you can turn Brilliant Color back off if you wish.
I preformed my best/dark room calibration using Cinema mode as a starting point. I was able to copy Cinema over to User 1 and rename it Night. Brilliant Color is off by default in Cinema mode and I left it off for my calibration.
Sharpness was defaulted to 8, I left it at 8. Pixel Enhancer 4K was set to 0. I found I could push it to 5 before seeing any objectionable artifacts when viewing 1080p content. There are 2 more enhancements called DCTI & DLTI, both are off by default and I kept them off. I kept Noise Reduction to 0.
Most of the time contrast set at its middle, default position is as high as you want to go, pushing the light output just before clipping. In Cinema mode I was able to push it 3 clicks to 53 eking out a few more lumens before clipping and leaving just a pinch of headroom.
Cinema out of the box performed decently but it did show 4 – 6 DeltaE between 10 – 100 IRE. Remember we want to be below 3 and I always strive to hit 1 or less if the projector is capable. The average color temp was 6850K range, a bit cooler than our target of 6500K (D65). After calibration, I was very pleased to hit 1 or less DeltaE across the entire grayscale (10 – 100 IRE)
I usually target a 2.4 (BT.1886) gamma for my best/dark calibration but found that the projector is really tuned to a 2.2 curve. When I tried to do a 2.4 I had issues with lower color saturation points (20, 40, 60, 80) being over saturated. Switching to a 2.2 gamma brought those mid-level measurements closer to their (REC.709) targets. After calibration I got an average 2.19 gamma.
Overall there were no real surprises with my best/dark room calibration. All of the controls work as there supposed to and yielded exceptional results with pleasing, natural colors and skin tones.
Measurements taken at Mid Zoom with Normal Lamp.
Average Gamma Pre-Calibration: 2.16
Average Gamma Post-Calibration: 2.19 @ 851 Lumens
White Balance calibration settings for Cinema (user mode 1).
For my bright room calibration, I used Vivid TV mode. The before calibration DeltaE was very similar to Cinema (user 1) with errors in the 4 to 6 range. After calibration, I was able to get DeltaE down to 1 or below. Brilliant Color was on by default and I left it on as it helps increase the white level output that were looking for in a bright room calibration.
Like with Cinema (user 1) I was able to push contrast to 53 before clipping and set sharpness to 8 and Pixel Enhancer 4K to 5. DCTI & DCLI are both on by default, I turned them off. Noise Reduction was set to middle, I turn that off too.
Default gamma in Vivid TV is set to BenQ which is also know as an ‘S’ curve that overly lowers the dark end and overly brightens the high end of the grayscale making for a more contrasty picture. I set the gamma to 2.2 which actually measured 1.95. My target for calibration was 2.10. After my grayscale calibration I got an average gamma of 2.11.
Average Gamma Pre-Calibration: 1.95
Average Gamma Post-Calibration: 2.11 @ 1394 Lumens
White Balance calibration settings for Day mode.
Finally, I did a 4k/HDR calibration. I used User 2 mode and renamed it 4k/HDR. I kept all of the basic controls at their default (50) values. With the white balance defaulted to Cool, average grayscale was 7500K. After setting it to Normal and performing a white balance calibration I was able to get it down to 6500K.
Brilliant Color was on by default and I left it om to help maximize white level output. Sharpness was defaulted to 9, I left it at 8. Pixel Enhancer 4K was set to 3 and I left it there. DCTI & DLTI, both are off by default and I kept them off. I kept Nosie reduction to 0.
When you feed the HT2550 a 4K/HDR signal it swaps out the Gamma control for HDR Brightness with values ranging from -2 to +2. HDR Brightness: -1 measured the flattest and closest to the EOTF target, however when watching various UHD blurays 0 seemed to fair better. Although I did not spend a lot of time viewing content I did notice that performance (i.e.shadow detail, muddy faces) varied a lot from scene to scene, some looked better at 0 (or even +1) and others at -1.
Pre-Calibration EOTF (HDR brightness 0): is overly bright from 0 to 60IRE.
Post-Calibration EOTF (HDR Brightness -1): is closer to it’s target @ 1554 Lumens
White Balance calibration settings for HDR mode.
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