JVC DLA-RS640 ISF Calibration
LCoS – JVC DLA-RS640 Projector
Introduction
So after spending all that hard earned money and hours trying to make the image look just as I had imagined it, my patience was running thin. HD SDR looked exceptional in both THX and Cinema modes and with the available menu options, you could make the image look virtually anyway you wanted…..almost all of them outstanding. But 4K never ‘cut the mustard’. Yes, it looked good, after hours of tweaking, but not what I had come to believe was possible from this projector. I needed an experience ISF calibrator who knew this projector inside out!
I had already used one local ISF calibrator for my BenQ, but this time I was looking for personnel recommendations for one that was intimately familiar with the JVC projector, and how to set it up for both UHD and WCG. Also having knowledge about the required OETF (custom) curves, and what would look the best for MY room and screen. Unfortunately, it turns out, setting up a projector to produce a really good 4K images isn’t that simple.
So after talking to others in a similar situation who had contracted with various ISF calibrators, reading several on line reviews, and the associated AVS Forum thread, I finally selected ChadB from Ohio.
I contacted ChadB by e-mail, and within 24 hours was told that his next tour for my state would be in October 2018….could I wait that long? Well, I had no choice! Anyway, I had to put at least 100 hours on the bulb and that also gave me more time to familiarize myself with all the projectors menus. Continuing to experiment with various 4K menu options.
Weeks past, then the e-mail arrived. ChadB had selected the day he wanted to visit, and regardless of what that day was to be, I said yes.
The day arrived, and waiting patiently, my heart raced as I saw ChadB’s’ car pull up to my house, this was it, I was about to enter video Nirvana! Read on.
We’re Off.
Knowing approximately when he was to arrive I turned my projector on one hour in advance to ensure that it was well warmed up and settled down ready for the long haul. HT air conditioning on, and refreshment at the ready, I welcomed Chad into my home.
It took Chad about 30 minutes to set up all his equipment, the pistol trigger was pulled, and we were off to the races.
Chad was just fine about me ‘hovering’ around him as he executed the various calibration routines. I wanted to see what was involved in correctly calibrating HDR. I have calibrated SDR projectors before, but didn’t own any suitable equipment for 4K calibration nor did I have any experience in this area. I hoped that just a little of his knowledge would rub off on me so that when I purchased my own 4K calibration system I would be able to maintain what Chad was about to do, as the bulb gradually losses it brightness and color output with time and use.
The whole process took about 5 hours. Besides being a really helpful and friendly guy, Chad was unbelievably thorough and anal, not leaving anything to chance. He fully calibrated the base projector for both SDR (REC709) and HDR (DCI-P3), loaded custom gamma curves for HDR and calibrated all iris modes. The results below speak for themselves, just one word; Amazing.
This will be an annual event and I have decided that I do not need to buy any calibration hardware now!
Calibration Results
What follows are the before and after graphs for both HD standard dynamic range (SDR) and 4K UHD high dynamic range (HDR). Chad created an SDR and HDR selection. SDR was calibrated to REC709 and HDR was calibrated to DCI-P3. The HDR option also had three custom gamma curves providing different levels of brightens to suite the content.
Standard Dynamic Range – HD SDR
High Dynamic Range – 4K HDR
Review and Discussion
If you can in anyway fault any of the AFTER graphs please let me know. Gamma curves are a personnel choice and are optimized to provide the visual look that was felt optimum for both SDR and HDR. Other calibrated gamma curves can be selected for both SDR and HDR.
The entire calibration was performed with my Panamorph lens in the light path in order to compensate for any losses. The focus and convergence having perviously been optimized. The projector is now permanently operated in this mode because the lens uses the entire projectors light output giving approximately 30% more light and my screen is 2.35:1. The only minor disadvantage is that there is a very small amount of barrel distortion at the top and bottom picture edges that is moved off into the black surround. There is no observable deterioration of image focus. I have very few 16×9 movies but if required they maybe mapped to the screen by dropping the screen masks and selecting a different stretch mode in the player or projector.
Low Brightness Mode
In low lamp mode the SDR image provided a screen illumination of 17 Foot Lamberts with the fixed iris closed down by 10 clicks. The recommended viewing illumination is 16 Foot Lamberts. With the iris closed down there was no need to use the automated iris to improve blacks as they were superb without it.
The HDR image in low lamp mode with the manual iris set at 0 provided 98 lumens which is bright enough to create a stunning HDR image due to the black levels being so low.
High Brightness Mode
There is no reason to use high lamp mode for SDR as I can open the iris if I require any more brightness which I do not. More brightness simply causes me to ‘flinch’ when the image cuts between dark and bright scenes.
For HDR, high brightness certainly provides more punch for those bright scenes and specular parts of the image creating an illumination level of 130 Lumens. However, I felt that the wear and tear on the bulb did not warrant the improvement in the image impact……unless I was trying to impress somebody! It also raises the black level to a point that became a little distracting for very dark scenes.
Auto Iris 1 and 2
Both Auto 1 and Auto 2 were fully calibrated for both SDR and HDR. Activating either certainly improves black level but their action is observable on occasions. So with the current black levels I generally keep them off unless I am looking to improve the blacks of space in some sci-fi movies.
Colors
SDR REC709 provides a 98% coverage, HDR DCI-P3 provides a 98% coverage.
All I can say here is that I cannot imagine colors that could be both more saturated or pure. They come very close to what I see at the source in the professional broadcast monitors that I view in the 4K HDR broadcast and production facilities that I am involved with.
Contrast Ratio
Not directly measured for either SDR or HDR.
The on/off native contrast ratio of any projector cannot be altered through calibration. It is inherent in the design of the projector. So why bother measuring it if you cannot improve it. Maybe just for interest? I can add dynamic iris control to improve the dynamic contrast range but that improvement varies over a wide range depending upon how you set up the two iris’s and what lamp power is in use (and projector distance from screen). My two auto iris modes are fully calibrated to support the correct gamma performance as they operate. So I am sure that over time I will try both modes, but for now I do not feel that I require them, and you can occasionally see it operate on certain types of material.
In my case all I cared about was that the blacks were black, deep black…….and they are. That is one of the main reasons I purchased this specific model. So why ‘sweat it’ over a on/off contrast ratio that you cannot fundamentally improve and possibly make yourself unhappy.
The other issue for this projector is that the native black levels are so low that accurately measuring them can be difficult and tiny errors in the measuring system and technique can give rise to significant errors to the calculated contrast ratio. So I let my eyes be the judge.
Focus and Uniformity
Just one word, excellent.
In summary the images in both HD SDR and 4K HDR are stunning in terms of chrominance, saturation, black levels, shadow and skin detail and skin tone. With luminance levels that are more than sufficient to provide an excellent dynamic range. The focus and image uniformity are also quite excellent across the entire screen.
Very Happy that I choose HDTVby ChadB for my calibration.
