Posted on July 29, 2018 By Eric Pfoutz
Optoma UHD51A A Smart 4K UHD Projector Review – Calibration Settings: Calibration Presets Notes, Best Mode Calibration, Brightest Mode Calibration & 4K Calibration
Note: The projector had over 76 Hours on the bulb before I calibrated it and took the light measurements. A brand-new bulb will most likely have slightly higher measured lumens.
The UHD51A has 8 picture modes: Bright, Game, Cinema, Reference, User, HDR, HDR Sim & 3D. I spent most of my time with Reference, User and HDR. For reasons I don’t understand Cinema, Game, Reference & HDR Sim all have their default picture settings at crazy levels. Contrast as high as 30 (50max), Brightness -15 Tint -16, color 25.
Brightness set to -15 effects peak whites, and it shouldn’t. At -15 not only are the blacks crushed, the peak lumens drop also. For example: Reference mode loses 110 lumens with Brightness at -15 vs 0. Contrast set to 30 does not increase peak whites at all, it just causes major clipping. If you’re not going to adjust any settings then at a bare minimum put the projector on User mode because it’s the only mode other than Bright mode that has the default picture setting at 0.
All modes default with Brilliant color set to 10 except for Reference mode which is set to 1. When settings setting the picture controls to the same values, Cinema, Reference and User modes all measure the same. During my calibration of UHD51A I experienced an issue with white level clipping. Basically, no matter what mode I was in the whites would clip at 232 no matter where or how low I set the contrast.
I preformed my Best/Dark Room calibration using Reference mode as a starting point. Brilliant color is set to 1 (out of 10) by default and I left it there for my calibration. Sharpness was defaulted to 8, I set it to 3. I kept Dynamic Black off for the calibration but turned it back on when I was finished. I left PureMotion off.
As I mentioned earlier, Reference mode out of the box performed poorly due to the fact the basic picture controls were set far from their ‘0’ (normal defaults). Just to make sure someone didn’t set these values be for I got my hands on the projector, I did a reset on all of the modes and they always went back to these over/under driven values. DeltaE ranged from 7 on the bright end of the grayscale to 2 on the lower. Gamma was crazy bright going off the chart at 1.6 at 90IRE with an average of 1.92. Grayscale was average at an 7300K average. White clipping was off the chart due to contrast being set to 30.
Once I set the basic picture controls (contrast, brightness, color, & tint) to ‘0’ the images improved a bit and got brighter (834 lumens) too. After white balance calibration I was able to bring gamma very close to my 2.4 target with a 2.35 average. White balance dropped to a 6500K average and the resulting DeltaE lowered to excellent .5 to 1.5 across the entire IRE range. After my CMS calibration (see advance cal page) I’d say the UHD51A performance is similar to other 4K DLP projectors in its class.
Measurements taken at Mid Placement with Normal Lamp.
Average Gamma Pre-Calibration: 1.92
Average Gamma Post-Calibration: 2.35 @ 834 Lumens
White Balance calibration settings for Reference mode.
Delta E is a metric for understanding how the human eye perceives color difference. The term delta comes from mathematics, meaning change in a variable or function. The suffix E references the German word Empfindung, which broadly means sensation. Simply put, look at Delta E as a measure of grayscale/color accuracy. 3 and under is considered ‘Excellent’ and imperceptible by the human eye.
Next up I did a Brightest calibration using User mode. The pre-measurements were a bit better than Reference mode because the basic picture controls were defaulted to ‘0’. Because I’m trying to get the brightest acceptable image as possible I left Brilliant Color set to 10. After calibration, both the gamma and the grayscale hit their respective targets of 2.2 and 6500K (D65) with a DeltaE of 1 or lower from 10 – 90IRE, 100IRE hit 2.
The overall results were much like what I got from Reference mode with the only real difference of a slightly lighter 2.2 gamma target and brighter image at 1195 lumens.
Average Gamma Pre-Calibration: 2.17
Average Gamma Post-Calibration: 2.05 (target 2.10) @ 1195 Lumens
White Balance calibration settings for User mode.
Lastly, I performed an UHD 4K/HDR calibration using HDR mode. Contrast default was 25 and Brightness was 2, I left them both there. White balance averaged 7500K with Color Temp set to the D65 preset. Color was set to -19 which seems very odd, however I discovered that I actually had to lower it to -22 because I it was over saturated at -19. Problem is the lower you set color it reduces the outer 100% saturation points shrinking the color gamut, but it does help improve the mid saturation points (80%, 60% etc) as they tend to be over saturated at -19 color and improve a little bit at -22.
After calibration, I was able to get the DeltaE down from 6-10 range to about 2-4 except 60IRE that hit 11. Brilliant Color is set to 10 by default and I left it there as it increases the white lumen output and we want as much as he can get for HDR.
The UHD51A has 4 HDR presets found under Dynamic Range (Standard, Film, Bright & Detail) The default is Standard and it’s the 2nd brightest with Bright about the same. Film and Detail are the closest to our ETOF target with Film slightly brighter. Turning gamma down from the default of 1.8 to 2.0 put Film dead on target except for running out of gas around 50IRE. Unlike other UHD projectors, here you can mix and match gamma and HDR modes.
I recommend trying setting Gamma to 1.8 & HDR Picture Mode to Film or set Gamma 2.0 & HDR Picture Mode to Standard. I think overall, I prefer 1.8 & Film because it has a richer more film like appearance. With UHD disc’s I found sharpness at the default of 14 over processed so I turned it down to 1 and left PurMotion off. Peak light output measured slightly higher than my Brightest mode at 1254 lumens
Measurements taken at Mid Placement Normal Lamp.
ETOF (gamma) Post-Calibration: Film tracked fairly flat rolling off (dimming) around 50IRE @ 1254 Lumens.
White Balance calibration settings for HDR mode.
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