JVC HD-750: mini-review, first impressions & calibration attempt...

Non of those appear to correctly track the reference gamma value you are targeting. looking at those I suspect A has a higher average gamma with B and C much being lower.

AVI

Thanks AVI, but I was only offering these presets to others users without a meter (or the will to tweak their own gamma), who may want to pick one of these presets not knowing which does what. ...

Simply by selecting them, I could see which one I preferred (none in fact) but I was curious to compare the graphs.

Once the work was done, I decided to share the results:D. By the way, did you have a look at the original gamma curves attached to my main gamma post above? They are much clearer than the luminance curves I just posted.

In my personal gamma experiment (I know, I sound like the Incredible Hulk:D), I was after a 2.3 average in my attempt posted above (the one that says "after gamma correction - 2.4 reference").

This is more or less what I got, and I'm going to try the same thing with 2.2, as 2.3 average may be slightly to dark to my taste (the blacks are slightly crushed).

So in my next attempt I'll set a 2.3 reference in the PJ, aiming for a 2.2 average/effective curve.

I'll post the results!
 
I intend to check the 10IRE, 20IRE and 30IRE with the Tecpel for luminescence as the targeted % of the 100IRE (the figures you can look up for the chosen gamma), have you done the same ?

I thought this might be more accurate ?
 
By the way, did you have a look at the original gamma curves attached to my main gamma post above? They are much clearer than the luminance curves I just posted.

Hi Manni01

No I was just commenting on the above graphs. :)

AVI
 
I intend to check the 10IRE, 20IRE and 30IRE with the Tecpel for luminescence as the targeted % of the 100IRE (the figures you can look up for the chosen gamma), have you done the same ?

I thought this might be more accurate ?

In my experience the Tecpel and the i1 can't measure the same as one is facing the PJ, the other one the screen. I fear it would create more problems than provide solutions, and frankly it is time consuming enough as it is:).

With the multiple dark readings enabled, I am more or less satisfied with the accuracy of the i1/HCFR/Calman. It's not perfect but it's good enough to reach a result that makes a difference to the eye;).
 
My only real concern was luminescence particularly at 10% my curve looked good at that point but because the value is so small .6% of 100IRE from memory, it looks good on the graph but when measured for absolute value was less an 70% of the value it should
 
Jeff and LovingDVD have both released new versions of their custom settings.

I tried them both and they have done a great job.
They have both fixed some minor issues which have brought their settings even closer to Rec 709, with all the added benefits of custom settings compared to THX: custom gamma, advanced sharpness controls, direct access on the remote;).

Upgrades and links to the most recent versions in this recap post, which I will try to maintain on AVS until Mark P produces a proper FAQ:

Official JVC RS20 / HD750 Calibration and CMS thread - Page 39 - AVS Forum

I will not post further updates - re third party custom settings - here, so please check this link from time to time for any updates. I will refer there back to the first post of the calibration thread when a proper FAQ is ready.

Many thanks again to Jeff and Ric for the fantastic work they've done:clap:.​
 
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Hi

I'm worried that something may be wrong with my 750. Stepping though the lens aperture control seems to have no affect at all? am i missing something?

P.S Thanks for the settings Manni:thumbsup:

Did you ever get to the bottom of this? As Manni mentioned you should definitely hear a motor clicking as you change the iris setting. I was wondering if your unit had gone bad, perhaps with the iris stuck in the closed or near closed position?
 
Did you ever get to the bottom of this? As Manni mentioned you should definitely hear a motor clicking as you change the iris setting. I was wondering if your unit had gone bad, perhaps with the iris stuck in the closed or near closed position?

Still waiting for my dealer to get in touch. Looks like the iris never worked as i have never heard anything when adjusting it. I do hope it is stuck in the closed position as i have lost alot of light output.

Thanks for your hard work and sharing your settings:thumbsup:
 
For those of you who are using an x-rite EyeOne Display 2 (or LT), I recently asked a few questions to Spectracal as I had a few teething problems when installing Calman 3.2 and Derek has sent me some really useful information, which I though I would share with you.

As I didn't experience an immediate and obvious improvement when I first used Calman, I expressed my concerns regarding low light readings and the lack repeatability when working on the greyscale with the i1, and asked whether reading from the PJ would help or not.

I'll split the info in Calman specific and non Calman specific, so that HCFR users are not confused:

Non Calman Specific:
1) Regarding accuracy in low light, in Derek's experience, the diffuser on the i1 (which you have to use when reading directly from the PJ and not off the screen) is not very accurate. Also in his opinion the i1 is accurate enough in low light to be able to read fine from the screen. So his advice is read from the screen rather than the PJ, with the i1 it's the best thing to do.
2) Regarding the repeatability issue, Derek said that "The D2 can be sensitive to placement. If you look on the bottom you will see 4 sensors. If one of those sensors is seeing a pixel structure or shadow and not seeing the same light as the others and you will get different light. One way around this is to pull the D2 back a bit more or try a different position". I found this very interesting, and had definitely not noticed/paid attention to this. I will be more careful in the future that I am no too close to the screen, as it may help (my tripod had the i1 about 2-3 inchs from the screen). I did try to find the best orientation to maximise fL at the beginning of each session, but I will try in the future to be sligthly off-axis to make sure that when I aim at the centre of the window, the shadow can't be in the sensors window at all.

Calman specific:
1) I was wondering why the "low trigger" function was not available when the i1 is used. Derek explained that "the low trigger for the Display2 is not necessary, it has an exposure control so you can set the exposure from 0.5 to 4 seconds. In testing we have found 1.5 to be a good exposure time. You can extend it to 2-3 seconds if you like but the accuracy will be about the same. As for the low light handler in HCFR all they do it take multiple readings and a simple average because they don't have access to the exposure control like we do".

The following are just a few additional notes/tips from me, so take them with the usual pinch of salt:).

HCFR Specific:
1) Regarding Derek's statement above in case you've missed it in my last list of tips, selecting "average many reads on dark measurements" (in Measures/sensor/configure) greatly improves HCFR's accuracy and repeatability at 0-30 IRE, at a very reasonable cost of speed. I didn't have time to compare with Calman's method yet, but I'll let you know because one of the main reasons why I bought Calman was to see if a different handling of the hardware would save me buying an i1 pro right now. I do plan to buy an i1 pro at a later stage (when my i1 will start to drift), and plan to train the i1 to the i1 pro to get the best of both worlds (speed and accuracy), so I will need both licenses anyway.
2) I have also realised that if you don't check "use gamma reference to compute greyscale dE" (in Advanced /Preferences/Advanced), well, you imagine the consequence: you think your greyscale is great but in fact your luminance can be quite off the gamma value you are targetting at each IRE level, even if you average gamma is spot on, which is related to my earlier post re gamma.

So to summarise past tips with recent ones, in order to maximise the accuracy/repeatibility of the i1, I am doing the following:

- Always give at least 15-20mn for the lamp to warm up before starting measurements (standard practice)
- Measure off the screen - rather than off the PJ with the diffuser - as it seems preferable with this meter (apart from the fact that doing so takes the screen into account, which is of course generally preferable)
- Set the i1 slightly off-axis on its tripod when pointing at the centre of the window to make sure no shadow can affect one of the four sensors.
- Make sure I set the iris of the 750 at the same setting if I plan to compare with previous measurements (if you need proof of this, close/open the iris while you are doing a continuous reading, and you'll see the RGB values drifting accordingly. Not by much, but enough to make a difference when reading a greyscale).
And, if using HCFR:
- Check the "average many reads on dark measurements" (to improve low light accuracy)
- Check the "use gamma reference to compute greyscale dE" (to make sure my dE reflect gamma as well as RGB)

Again, apologies if this is obvious to everyone, it definitely wasn't to me:D... As usual, comments and corrections if your experience is similar/different are welcome.

I plan to work on my greyscale targetting a 2.2 gamma (although I like the deeper black levels I get with 2.3, I lose too much detail to my taste in dark scenes), so I'll keep you posted if I see any improvement using this methodology, and also re using Calman versus HCFR.
 
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Sorry slightly OT

Anyone know if the Isco 2 will work on the HD750 at 18 foot throw on to a 117.9" wide 50" high 2.35 screen

cheers
 
Manni, just to pick up that you said the diffuser isn't very accurate, then you seem to say to use it when measuring off screen.:confused: I've been struggling to get consistant readings one day to the next, but I think this is due to imperfect uniformity and even a slightly different position can pick up an area that has slightly more red or green....probably not such a problem on the HD750. :)

Just looking in as I still hope to get one of these machines at some point in the future. :thumbsup:
 
Manni, just to pick up that you said the diffuser isn't very accurate, then you seem to say to use it when measuring off screen.:confused: I've been struggling to get consistant readings one day to the next, but I think this is due to imperfect uniformity and even a slightly different position can pick up an area that has slightly more red or green....probably not such a problem on the HD750. :)

Just looking in as I still hope to get one of these machines at some point in the future. :thumbsup:

Always nice to see you're still with us!

I've added punctuation to clarify my sentence, I definitely didn't mean to use the diffuser when mesuring off the screen, hope it's clearer.

Uniformity definitely not an issue on the 750 (at least on mine:D). If you're using window patterns and not full fields to calibrate, it shouldn't be such an issue on the AE-3000 either, or is it?
 
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Sorry slightly OT

Anyone know if the Isco 2 will work on the HD750 at 18 foot throw on to a 117.9" wide 50" high 2.35 screen

cheers

This works out to a throw of just over 2.4 so you should be OK with the ISCO II. It will be worth taking as much as time as possible to ensure correct alignment so that you minimise pin cushion and get good focus. The pin cushion was the biggest weakness of the II and one of the main reasons it is discontinued.
 
CraigR, an experienced installer/calibrator, has posted on AVS a link to a very detailed calibration/setup review of the RS-20 (HD-750), along with details of results obtained with a Radiance XE (beta), and a comparison with THX and RecLDVD.

He confirms (using professional equipment) the findings regarding the limitations of the CMS already observed here and on AVS in the calibration thread. Although one should keep in mind that he is a reseller and installer for Lumagen, his description of the limitations of the internal CMS are very accurate, and backed-up with graphs and data.

His post can be found here: http://www.avsforum.com/avs-vb/showthread.php?p=15820551#post15820551

It would be nice to hear soon from JVC about the CMS.
The last we heard was from Elliot in the firmware upgrade thread over on AVS about a week ago (JVC RS20 Firmware Upgrade Request List - Page 5 - AVS Forum), where he confirmed JVC was working on revised CMS settings:smashin: and was mentioning a possible visit in the UK from the head designer, who kindly offered to meet some UK members to discuss the CMS issues.

Let's hope GaryB or Elliot will chime in soon with some more encouraging news:)...
 
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CraigR, an experienced installer/calibrator, has posted on AVS a link to a very detailed calibration/setup review of the RS-20 (HD-750), along with details of results obtained with a Radiance XE (beta), and a comparison with THX and RecLDVD.

He confirms (using professional equipment) the findings regarding the limitations of the CMS already observed here and on AVS in the calibration thread. Although one should keep in mind that he is a reseller and installer for Lumagen, his description of the limitations of the internal CMS are very accurate, and backed-up with graphs and data.

His post can be found here: Official JVC RS20 / HD750 Calibration and CMS thread - Page 47 - AVS Forum

Manni

Thanks for the link. A great pitch for the Radiance.

Quick question re "colour decoding" -

"Fortunately the RS20 has no such errors. With color and tint set to zero in the JVC color decoding is correct. This projector has no red push or any major errors in its color decoding when feeding RGB or 4:2:2 HDMI into the RS20"

I thought (maybe wrongly?) that colour decoding related to chroma subsampled signals not RGB. Does this also apply RGB ?

AVI
 
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I thought (maybe wrongly?) that colour decoding related to chroma subsampled signals not RGB. Does this also apply RGB ?

AVI

I'm afraid you'll have to ask him (he's monitoring the AVS calibration thread and his replies to our questions are very detailed). He's the engineer, not me:)
 
Using the feedback from Craig in the link above, I have produced some new settings (which I called RecJVC as they are pretty much a reductiong of the original gamut) and would be interested to get some feedback from those who have the time to try them out.

The idea is to use only the controls that are linear in the CMS (saturation) and the general color control to try to correct the oversaturated gamut.
It is a compromise regarding accuracy between red and green, but there is no clipping and it seems to track very well between 75% and 100%.

It is definitely not as close to Rec709 as THX with color=5, but I find it much more pleasant to watch, with a lot of depth and pop, and pretty accurate skin tones, especially with color kept close to 20 to 22.

If you'd like some detailed explanation, please have a look here http://www.avsforum.com/avs-vb/showthread.php?p=15826533#post15826533 and in the following few posts (preferably after having read Craig's review), but if you just want to punch the numbers in, here are the settings I used:

Contrast:0
Brightness:0
Color:22 (adjust to taste between 15 and 30. Best skin tones for me were around 20, better green/yellow/cyan will be around 25-30. More than that and other colors suffer too much. To date the compromise I prefer with most material is 22).
Tint:0

Custom settings for Color Temp just for reference (please do not use as it's unlikely to help unless you lamp is close to 300 hours like mine). Unhappy with my 100 IRE as it's a bit off, but that wasn't the topic of the day
smile.gif
.
Gains:
R=0
G=0
B=-54
Offsets:
R=0
G=-2
B=-1

Custom gamma with a 2.3 ref that tracks at 2.2 (didn't have time to really work on it, but it's close enough as all dE are <4).

CMS:
All values for hue and brightness at zero (to minimise clipping and keep linearity).
All values for saturation at -30
(I know it sounds too simple to be of any use, but please be open minded, and try it with your eyes
biggrin.gif
).

Please let me know what you think (positive or negative, if you like RecJVC, thank Craig, if you don't, blame me:rolleyes:)
 
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Using the feedback from Craig in the link above, I have produced some new settings (which I called RecJVC as they are pretty much a reductiong of the original gamut) and would be interested to get some feedback from those who have the time to try them out.

It is a compromise regarding accuracy between red and green, but there is no clipping and it seems to track very well between 75% and 100%.

It is definitely not as close to Rec709 as THX with color=5, but I find it much more pleasant to watch, with a lot of depth and pop, and pretty accurate skin tones, especially with color kept close to 20-22.

Manni

Did you record any dE94 data on the new setting at 75% and 100% ?

AVI
 
Manni

Did you record any dE94 data on the new setting at 75% and 100% ?

AVI

To be honest I'm not very interested in comments on the numbers (they are off, although not more than other custom settings, and better than ootb especially at 100% stim), but if you want to have a look at the raw data please follow my link above for a more detailed explanation, I have posted a zip with all the HCFR measurements on AVS. The most relevant files in the zip are the one called RecJVC, with all the data at 75% and 100%.

What RecJVC does basically is move some of the error on x,y (gamut) to Y (luminance). So you get a gamut closer to Rec709 (although far from hitting the reference, I am very well aware of it), with more error on Y. But because there is no clipping or undersaturation at 100%, it may be an interesting compromise. Also the fact that green is still oversaturated compensates the lack of brightness compared to spec, and vice versa for red. So the numbers don't look great, but I find the results visually interesting enough to ask for some subjective feedback.
 
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I've slightly revised my RecJVC settings to try to address a slight undersaturation of blue, improve yellow and balance colors a bit better with a general color around 15.

Here are the settings for RecJVC v2:

If you want best skin tones, color=10 to 15
If you want richer colors, color=15 to 20
Anything in between according to taste as usual. Below 15 will make green/yellow really dull, above 20 will start to make skin tones clownish.
I calibrated with color-15, and this is my prefered setting atm.

CMS settings:
Hue and Brightness at zero for all colors
Saturation:
Red=-28
Yellow=-20
Green=-30
Cyan=-24
Blue=-24
Magenta=-30

I tried to find a better balance between red and green by lowering color to 15 (from 20 to 22) and red sat to -28. This gives lower dE at 75% and 100%, and avoids being at the extreme of the controls which I noticed is better for some colors.

I didn't have much time to test these revised settings with real material, but I quickly watched a couple of clips and they looked ok.

More details (and HCFR files at 75% and 100%) in the calibration thread on AVS here Official JVC RS20 / HD750 Calibration and CMS thread - Page 49 - AVS Forum

It would be nice to get some feedback (positive or negative) if anyone has tried these.

The feedback on AVS is quite positive, especially from users with a higher gain screen, who may benefit the most.

RecJVC is slightly darker than other settings, but with the benefit of richer, more vibrant colors, without any clipping.

So you get much more detail, especially on green, and opening the iris slightly (one notch) is enough to compensate for the slight loss of brightness.
 
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For those who are not monitoring the Firmware upgrade thread over on AVS, here are some good news: a firmware upgrade for the 750, which will hopefully improve the CMS, is finally confirmed.

I just heard from my dealer (Elliot from PJ Hifi in Guilford) who has "been in discussion with Alex (Head designer in Japan) on many points", and who confirms he'll "have a beta firmware *soon*".

A trip to the UK from Japan for Alex is still on, they are just waiting for a date from him.

A date for the firmware itself wasn't confirmed officially, but I would say weeks rather than months (call it my own guesstimate). Remember this is beta, so wide availability may take a bit more time.

I'll let you know as soon as I hear more (if I'm allowed to, which was the case this time!:)).
 
Excellent news thanks for the info Manni. Hopefully this will resolve the cms difficulties as you say and tweak all the other things on the wishlist as well :thumbsup:
 
Manni, Hi

Wow 300 hours :eek: I'm only on 344 with my 'old' 100. How is the brightness holding up ?

I am due to e-mail Steve Carter as I spoke at the Bristol Show, last night measuring the contrast I was only seeing 58 Lux.......... on the ANSI grid
 
Manni, Hi

Wow 300 hours :eek: I'm only on 344 with my 'old' 100. How is the brightness holding up ?

I am due to e-mail Steve Carter as I spoke at the Bristol Show, last night measuring the contrast I was only seeing 58 Lux.......... on the ANSI grid

300 was a few weeks ago... I've reached 368 now:D. I guess it's because watching films is part of my job...

Brightness seems to have stabilised since I hit 300 hours, but I haven't measured it recently. I can, however, open the iris wide without being blinded, so I'm sure it's a bit down. I'll do take some measurements when the firmware upgrade arrives and I get the meters out for a new round;).
 
300 was a few weeks ago... I've reached 368 now:D. I guess it's because watching films is part of my job...

Brightness seems to have stabilised since I hit 300 hours, but I haven't measured it recently. I can, however, open the iris wide without being blinded, so I'm sure it's a bit down. I'll do take some measurements when the firmware upgrade arrives and I get the meters out for a new round;).

Great, good to hear from you :smashin:
 

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