With regular non-HDR projectors, it depends on whether your room is a bat cave, has some ambient light or an open living room. For bat caves, you don’t need a high lumens projector. For some ambient light, a higher lumens projector with a grey screen will give you more contrast. For a living room, a light cannon with ambient light rejecting screen may give you satisfying results.
Does HDR make a difference? Certainly on my OLED with HDR, the whole room lights up when the scene has large highlights e.g., car headlamps. And in a way that is realistic, but almost painful to look at the screen. I think brightness for a projector is important, but only in a bat cave and the projector has to have a really high contrast ratio to achieve the dynamic range of OLED. I’m not sure projectors are there yet
Since Lumagen cannot process a Dolby Vision signal, the question for me for DV content:
Is Lumagen’s algorithm based DTM on the HDR10 layer better than Dolby Vision’s DTM, which is designed by the Studio.
It would therefore make sense to me to pass the Dolby Vision processed layer to the Lumagen to see if Lumagen can already improve on an image that is accurately tone mapped by the Studio
At the time of this writing, 4K projector itself is unable to process DV…the only thing we can test is the DV variant - i.e. LLDV (Player-led) but we also know that Standard DV (Display-led) will simulate as close to the studio and director’s intent. I do hope Lumagen is able to include LLDV capability in the next firmware update, provided the founder Jim Petersen and his team find there is value in it. But until then I am not convinced that this is the best way to test DV and HDR10 with Lumagen as the penultimate device in the video chain. It should be a one device performing the transition.
FWIW as previously mentioned, I will be happy to give it a try if anyone willing to t-loan me a unit of the Vertex 2 to see if there are any significant differences in the PQ with Vertex 2. Do drop me a PM
+1. Many tests conducted on various OLED TV provided anecdotal evidence that HDR10 layer usually provides a brighter image compared to DV when DTM is engaged. Why is that so, nobody really knows. For projector, DTM is definitely a must-have feature to have good overall image with a more consistent luminance output.
Watched the 4K digital streaming version of Monster Hunter in 4K HDR and I have to say, this is by the far the cleanest 4K HDR transfer I have seen so far…the stream is authored at 1,000 nits. So it can be dim in some scenes for those not using some form of DTM. But if watching on a OLED or LCD/LED display, you should see plenty of details in both the day and dark scenes.
The image is derived from the Tom and Jerry movie (in 4K HDR - processed by Lumagen Radiance Pro Dynamic Tone Mapping - shot using iPhone 12 Pro Max)
Which image do you prefer? The left side is using colorspace SDR2020 while the right side is using the DCI-P3 color gamut. All the colors fall within the BT2020 colorspace but you can see there is a difference in the way it is presented. The most notable difference is the change in skin tones and the change in the sconce lighting as well.
The left for sure, looks so much more natural. The one on the right has too much reddish tone, looks unnatural. Unless she has just finished from some sporting event under the hot sun, the face should not be so red…
I bet everyone will be surprised if I say the SDR 2020 color tones are very close to Rec 709 and that is actually correct. Your eyes did not deceive you. The difference between a Rec 709 and SDR 2020 is the colorspace that it occupies. For SDR 2020, it occupies BT 2020 color boundary while the Rec 709 is within this boundary as well. If you switch from Rec 709 to SDR 2020, you will not experience a significant change in color tones and hues during normal Average Picture Level (APL) scenes, the only difference will be the specular highlights that SDR 2020 are able to showcase because of its wider color gamut compared to Rec 709.
For HDR10 content, calibrating a 3D LUT colorspace using calibration s/w could be a challenge due to the limitations of the color probe (colorimeter). Since different probes have different degree of tolerence in terms of black and white levels, this make 3D LUT calibration (purely on colors) extremely difficult since it varies with light intensity and the placement of the probe also plays an important factor in getting accurate results. This is the problem I have had faced all these years…In the end, I usually resort to calibrating 1D LUT (for grayscale - getting the RGBCMY on a flat line) and do away with 3 LUT calibration altogether.
The only sure way to dial everything in place, is to use SDR-based calibration test patterns to work with your calibration s/w and this will usually provide very good results since most projectors (2K/4K) provide extremely good Rec 709 colorimetry out of the box. The great thing about Lumagen Radiance Pro is the ability to color correct it at BT 2020 boundary when a SDR test pattern is being used. This allows plenty of “headroom” for low-nit display like Projector to take advantage of all those precious nit levels that you desperately need for a proper calibration. This is the reason why I advocate for the calibration of Rec 709 over the HDR 10 calibration which requires a good 3 LUT measurements to truly reap the benefits of HDR. By having a good baseline - i.e. Rec 709, switching to a a wider color gamut like DCI-P3 or SDR 2020 will yield better colors.
May have to read that a few times to understand it, but your picture on the right definitely has the “red push” I see when I set my HD Fury Primaries to DCI-P3 instead of BT2020 in the Dolby Vision data block. My BenQ projector is set to BT2020 and cannot be changed. I know you can change it with JVC projectors.
So the question is what is your Sony projector set to. DCI P3 or BT2020?
Definitely BT2020…the picture I took is for comparison. The Lumagen allows DCI-P3 to be used but the Projector must have the DCI-P3 colors dialed in to get it right.
There may be a need to recalibrate. To date, I think only Sony and JVC projectors can do DCI-P3 colours. But before that, we will need to find the “right” color preset first that closely track to the P3 colors.
Yes correct Desray. That is how it is done now. Including dolby vision calibration for LG TVs.
What it does is it disables the displays PQ EOTF but maintains the display in Peak Luma Mode
One can then calibrate the screen to its Normal 2.4 or 2.2 gamma targets , Calibrate grayscale as usual and the Peak RGBW primary targets
These primary values are then uploaded into the tv. the TV’s processing , with the information available on these data, will now automatically map the displays HDR capabilities to the EOTF target and REC2020 colour space.
This is the best approach for HDR calibration or dolby vision . Simple and easy
Still cannot beat the 3D LUT calibration, but is extremely effective for manually calibrating the screen for HDR and dolby vision
no sifu la bro… lol