CurtPalme.com Home Theater Forum

[dumalkin]

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Hi,
Yesterday at night I played with my new EyeOne Display 2 and projector.
Setup - projector is placed 4.5 meters from the wall and projects image ~ 3.6 meters diagonal (pretty big).
Room is dark (at night) but with bright walls and ceiling.
Projection is done on white-painted wall.
I used CalMAN free generator as image source.
I calibrated several projector modes, but the problem is the same and the curves look pretty similar, so let's focus on the one mode - Color1 (apparently calibrated by Panasonic to THX standard), and only on greyscale calibration (I'll try its CMS tonight).
Even before calibration things were pretty good (deltaE was around 10), using configuration suggested by some reviewers gave slightly better results (deltaE ~ 9).
After calibration I got the following (first line X, second y, third Y, fourth deltaE):
0.305043 0.308653 0.313421 0.312700 0.312530 0.313309 0.314053 0.313791 0.313028 0.311424 0.312632
0.332846 0.328357 0.331183 0.330146 0.328860 0.329495 0.331203 0.330294 0.329226 0.329594 0.332641
0.807606 1.586590 2.714053 4.089776 5.777388 7.796586 10.337400 12.739144 15.485907 18.626299 21.956169
8.8 3.6 1.7 1.0 0.2 0.5 1.8 1.2 0.3 1.5 3.1
Subjectively image looks slightly better if I compare old and new settings side by side.
So far so good.


But gamma is completely off - average 1.56 - it was so before calibration and almost didn't change after that.
Luminosity is around 6.4 ftL (Y=~22), pretty low, I know - but movies look alright and overall it doesn't give "too dark image" feeling. Also remember - I watch movies (and did calibration) in total darkness.

Luminance curve looks strange - it is over the reference, like I get too much output.
I tried to play with gamma controls but before going blind I'd like to get some advice:
I have simple gamma control and complex one.
Simple are just 3 sliders - allowing to tweak gamma low/mid/high channels. Complex method is 4 curves (R/G/B/Y) with 10 points each, that can be modified from their initial "straight line" position.
So - should I try to low everything (according to luminance curve) or raise everything (according to gamma curve) ?
Or I should give up and those low gamma values are due to wall (versus screen) and reflections - and to improve that I should redo my room ?
And - which parts of the image I miss by watching it on such low gamma - details on bright, mid, dark, overall contrast ?
Any help will be very appreciated.

BTW - great guide, 10x

[rjn24601]

My first question would be this- are you going to be watching movies on the projector from your PC? If so, great- if not, I would suggest using the DVD or Blu Ray player you are using with an appropriate test disc (such as AVS709- also free!). You will generally want to calibrate to the source you will be using as levels can vary from device to device.

I also have the Panny AE4000, and I ran a HCFR calibration last evening with my old Spyder II. Even with all of the inaccuracies of the Spyder I am still getting 10 ftL on Color 1 (and I do think that my particular Spyder's luminance measurements are quite a bit off the mark)- I actually think I am getting more than 10 ftL, but I won't know until my new meter arrives. My point is that you should be getting more than 6 ftL. Is your contrast set too low...? What sort of screen are you using?

The advanced gamma correction is pretty great for fine-tuning the greyscale. Focus on the RGB chart and look at the individual red, green and blue curves. If your greyscale is relatively accurate, you should only see a few bumps and dips around the standard for each line. Use the advanced gamma slider at the different input levels (ie: 50% = point 5 in the adjuster) to even out some of the bumps. You will not be able to effect 0% or 100% IRE, but you will be able to adjust everything in between. Very minor adjustments are all that should be necessary from 30 to 100 IRE.

I was able to get pretty remarkable results last night, though I do believe there are issues with my meter (being 3 years old). I am looking forward to having a go with the new meter. Hope this helps a bit!

[dumalkin]

Hi,
Yes, I am playing movies from the PC, and they are projected on white painted wall - simple paint, not GOO or something like this.
I got 6 FL in eco mode, don't remember what it was normal mode.

[ecrabb]

How many hours does the bulb have on it?

SC

[dumalkin]

Around 350, 90% in Eco mode.

[ecrabb]

Are you running cinema 1 color mode?

SC

[dumalkin]

I have Color 1 and Cinema 1 modes, they are different.
In Color 1 mode only greyscale settings can be changed, not individual colors.
And yes, most of the time I use Color 1 mode. When watching TV or in daylight I use Normal or Dynamic modes.

[ecrabb]

In this review:
http://www.projectorcentral.com/panasonic_ae4000_projector_review.htm

They're saying 550 lumens in Color 1 mode. They're also saying you lose 32% in Eco mode, putting you down around 376 lumens. Lose another 10% with bulb brightness drop, a little more if you're toward the longer end of the zoom range, and you could easily be below 350 lumens, which at your screen size, can easily end up sub-6 fL. Personally, I think that's too dim. Youre giving up on of the best things about digital - a nice, bright picture. I'd either turn off Eco mode or move the projector forward and use a smaller screen size.

I'm not sure whats going on with the gamma thing.

SC

[dumalkin]

My projector is about 4.5 meters from the wall, and projected picture is about 3.15 meters wide.
I tried to watch movies in Eco and Normal modes, and me, my wife and all my friends that were invited preferred Eco - Normal is too bright. May be it is due to reflections from the ceiling / walls, may be it is just matter of preferences, I don't know. I don't have problem with the brightness of the picture, only with apparently bad gamma.

[HogPilot]

Your average gamma and luminance curves completely agree with each other, which can be a bit confusing. Think of average gamma as describing how quickly the projector rises out of black. Here is a great depiction of various gammas:



Although it seems counter-intuitive, the higher the gamma value, the slower the projector comes out of black (depicted by the light blue line gamma = 2.2). The lower gamma value, the quicker the projector comes out of black (depicted by the dark blue line gamma = 1.

Your gamma and target luminance curve are directly tied together - the former dictates the shape and values of the latter, again illustrated by the image above. I would highly recommend downloading gregr's Display Calibration Calculator - amongst other nifty features, if you tell it what your target gamma and Y at 100IRE are, it will tell you the target Y at 10IRE-90IRE.

It looks like your greyscale is pretty decent - it's your luminance (and hence your gamma) that is off by quite a bit. I'd suggest using the Y control under PICTURE -> ADVANCED MENU -> GAMMA ADJUSTMENT -> ADVANCED to properly set the luminance at each IRE as close as possible to the target values spit out by gregr's calculator.

If you really want to gnat's ass things, you can use the individual R/G/B gamma correction (instead of the Y control) to tweak the greyscale and luminance at each IRE. This will be more time consuming but will essentially act as an 11-point parametric gamma/greyscale control.

[dumalkin]

@HogPilot:
Thanks, now it starts to make sense. I'll try it tonight.
So, if I get you correct, my projector comes out of black too fast (it is too bright ?). How it can be if total FL at 100 IRE is totally according to spec and is rather low ? It is device manufacturer defect, design problem or installation problem ?
Can projecting on the wall (as opposite to normal screen) can give such result ?
I thought this projector should work pretty close to "ideal" out of the box, without additional tweaking, and in greyscale department it did (deltaE < 9), and in gamma it is so off - strange.

[HogPilot]

[HogPilot]

[dumalkin]

As I wrote before, I have no problem with picture brightness.
I tried to get gamma to more "normal" values.
1. Although display calculator seems to be very handy, I can't get how to use it - every time I change gamma values of 10%-90% steps, maximal brightness at 100% level is changed as well, so I can't fix it in one pass, it is iterative process.
2. I got gamma values 2.18, 2.2, 2.26 and so on - first by lowering gamma settings in gamma Y curve, then by readjusting colors according to guide to keep deltaE small, and finally by adjusting individual gamma curves. In the end I got deltaE around 1.5, and gamma 2.18
3. Total maximal brightness increased by around 30% - don't know why.
4. Windows desktop looks more deep and in general - better.
5. But - when I play movie through player - I get no midlevel details, everything is too black. It looks like player doesn't use windows gamma settings (that was apparently way off, and was compensated using projector settings), and works with some other much more correct gamma - because when I use default gamma curves movies look very natural.
6. Conclusion - I shouldn't use software image generator but get calibration dvd instead, play it using the same player that is used for movies and retry everything.

Do you know any free downloable calibration dvd alternatives or I have to order commercial disks from Amazon ?

[rjn24601]

I think that is your best bet, for certain. The AVS709 disc is highly recommended. I have many calibration discs and this is the one I prefer. Do a google search and I'm sure you'll track it down. And it's 100% free! As long as you have a DVD burner. It even works for Bluray- which is sweet!

Hogpilot- terrific explanations, btw!

[HogPilot]

[dumalkin]

I repeated the whole calibration process using my player program and calibration disk from http://www.avsforum.com/avs-vb/showthread.php?t=948496 - "Patched" version. Can't understand the difference between all variations they have there ... I didn't burn it to DVD, just mounted .iso file on the file server and played it over the network - shouldn't matter for calibration purposes, I think.
Can't get menus to work, probably player problem, so I just played stream files (stream #11, if I remember correctly).
I proceeded as follows - first, set everything to "default", then made first measurement just to know where I am. deltaE was around 7-8, Gamma - 1.84.
Then I repeatedly played with Advanced Gamma curves (Y), to make gamma curve on HCFR as close as possible to 2.2
After several passes I got it pretty straight over all IREs. Then I took a look on RGB levels, and they were way off (just like they were before the calibration, may be even worse). Using the iterative technique from the guide I adjusted colors to give small (< 3) deltaE.
Obviously it messed up gamma again. So now I left gamma Y curve as is, and started to fix individual colors using color gamma curves. Stopped when I realized it is 2:30 am here, and I have better things to do - so 80/90 IRE are in rare (as opposite to "well done" conditions). Before they were "steak tartar".
Results - gamma 2.26, deltaE < 3 except 80/90 IRE where it is 3.6 and 4.9 respectively.
I watched several scenes in recently viewed movies and played with settings on the projector - comparing new and old versions. Difference is very subtle but clearly seen. Interesting theoretical question is why gamma has to be tweaked at all - due to projection surface imperfections, projector design / manufacturing defects, or something else.
I'll fix 80/90 IRE next time I have time, for now it looks good enough.

[HogPilot]

Dude, great job! You're definitely on the right track, and it looks like you'll have no problem getting those last two points to fall in line nicely.