82 replies to this topic

[sdixon]

DrP, on Jun 16 2009, 12:19 PM, said:

Let me know when you've departed fantasy dream land and made it back to reality and display devices and corrected the errors in the above quote (how can you fit so many errors in such a small space?).  When you do arrive back in reality world, would you mind answering the question raised elsewhere in response to another of your oddball statements - namely, how an end user would be able to select an incorrect colour matrix in the first place.... or is that question a tad too stressing for you?  As a last dig, why did you bring up colour matrixes in the first place?  Have you done a bit more reading since then and decided to try to back pedal a bit?  Do you need to 'clarify' your position as you did with your endless MPEG4 AVC progressive posts?  


As I've said before alanh is stuck in analogue days.  Not only in analogue days, but also in the days of vidicon tubes etc.  I hate to shatter your dream alanh, but I think you'll find CCDs are used these days.  You might want to look that up with google too.     Do some real research before you try to BS your way out of this one too.  You are now wandering into my field and I know all about the actual nature of 'leakage' when it comes to CCDs and the light I'm looking at you with makes your statement quite 'entertaining'.

...maybe you pair should get a room....

[kwarrior]

sdixon, on Jul 2 2009, 02:09 PM, said:

...maybe you pair should get a room....

No love lost here is there ? .....

[MarkTecher]

Just my $0.02 worth.  All video is supposed to be mastered to D6500K.  The "artistic" side of the creation however can be anything the studio wants.  The DVE disc does have some interesting information, however, it is simply a tool with limited use if you don't have a reference grey scale of 6500K to begin with.  Many video displays are preset much higher than 6500K.

[alanh]

Mark,
I agree that all TV has been balanced for D6500 from 1975 in Australia & Europe. The USA was using Illuminant C6770 but gradually changed to D6500.
Prior to that time the colour of the primary colours of Reg, Green and Blue (NTSC primaries) were unachievable in real life piture tubes.  When colour started in Europe the European Broadcasting Union specified realistic colour prmiaries. This is what we use for SD TV & DVDs. When the European primaries were specified the proportion of red, green and blue signals were left wrongly at the original NSTC values. (Luminance = 29.9 % R, 59.7 % G+ 11.4 % B ) With EBU primaries, this makes pale purple the sharpest image, since the luminance signal has the greatest bandwidth.

When the HD colour primaries were selected, it was decided to correct the proportions of red, green and blue to match the brightness of these primaries. (Y= 21.26 % R, + 71.52 G+ 7.22 % B ) This makes the shades of grey the sharpest image which is correct. These values are used in all HD originated DTV and for Blu-ray disks.

When the TV stations upconvert SD to HD they digitally decode the Y, C_r & C_b signals back to Red Green and Blue, they then rematrix the colours into Y, P_r & P_b. These signals are then "shapened up". The SD "Y" and the HD "Y" have different values except for black and white.

This is the reason why HD projectors should be adjusted using the Blu-ray DVE disc. Prticularly when using the physical colour filter and checking the colour of the display.

AlanH

[MarkTecher]

alanh, on Jul 5 2009, 04:36 PM, said:

This is the reason why HD projectors should be adjusted using the Blu-ray DVE disc. Prticularly when using the physical colour filter and checking the colour of the display.

It still does not solve the grey scale and the blue filter should be a "wratten 50" and I have read on the net that it is not quite correct.

[alanh]

Mark,
What is the problem with the grey scale?
The display has to be fed with various values of Y with the Pr and Pb @ 0 (digital level 128). Then you need to get the grey scale to appear grey against a grey scale card illuminated with light of D6500. The other way to do this is to use an Radiance meter (measures the radiated power from the screen and not the light from the screen) and measure each primary in turn. Each value should be identical. Very few people can use this method because of the cost of this piece of measuring equipment.

The coloured filters I was referring to are the ones provided with the disc.

AlanH

[DrP]

Holy hell.  alanh are you sure you want to recommend people use a meter to configure their equipment?  That certainly seems to contradict your previous statements.  Would you be willing to clarify your position on this matter?

[MarkTecher]

alanh, on Jul 5 2009, 07:52 PM, said:

Mark,
What is the problem with the grey scale?

Out of the box, my (all) BenQ is running about 8300K, not 6500K.  Red Green and Blue is not even aligned.  Some Sony's run as high as 9300K.  This means BLUE greys in video not grey greys in video and WILL affect every ithger colour we see.

Quote

The display has to be fed with various values of Y with the Pr and Pb @ 0 (digital level 128). Then you need to get the grey scale to appear grey against a grey scale card illuminated with light of D6500.

Does that card tool actually exist?  It may be useful on a CRT but not for a projector as you do not want to be adding light into the room.

Quote

The other way to do this is to use an Radiance meter (measures the radiated power from the screen and not the light from the screen) and measure each primary in turn. Each value should be identical. Very few people can use this method because of the cost of this piece of measuring equipment.

Is that the peice of gear with the "CYBERDYNE" logo on it?    

Quote

The coloured filters I was referring to are the ones provided with the disc.

Yes, and they are the ones said to be not accurate.

Edited by MarkTecher, 06 July 2009 - 07:11 PM.

[kathycoco]

hi all here:

Any one knows TI high-end multi-core TI OMAP3 Cortex A8 processor?

Which kind of electronic products adopting this processor?
What functions can the product Realize?


Regards
Coco

[Dacso]

This is a fantastic site. With plenty of useful information.

[MarkTecher]

Dacso, on Apr 5 2010, 09:21 AM, said:

This is a fantastic site. With plenty of useful information.

And lots for friendly members that like to contribute and help out where they can.

[jslayz]

Why is this unclear, debated and not very interesting or informative thread a sticky????

Anyone??????

J

[MarkTecher]

jslayz, on May 29 2010, 01:55 AM, said:

Why is this unclear, debated and not very interesting or informative thread a sticky????

Anyone??????

J

It was started with the best intentions, just was challenged and then went off course.

[himalj]

edited

Edited by himalj, 27 September 2010 - 02:50 PM.

[MarkTecher]

For the colour test patterns to work with the blue filter, the display must be running 6500K or the colour/tint will not align as intended.

[Yacano]

Hi, I was wondering if someone could help me with an issue I have found with my Projector.

I have noticed the image is not very sharp in the centre of the projected image and when I attempt to use the manual focus dial on the projector to tighten up the sharpness the upper or lower parts of the projection becomes blurry...

I noticed on the lense that there is a clouded section in the centre part and suspect this could be burnt.
is there a way to attempt to fix this without getting a new lense for the machine?

Thanks

[MarkTecher]

Yacano, on 09 January 2012 - 10:56 AM, said:

Hi, I was wondering if someone could help me with an issue I have found with my Projector.

I have noticed the image is not very sharp in the centre of the projected image and when I attempt to use the manual focus dial on the projector to tighten up the sharpness the upper or lower parts of the projection becomes blurry...

I noticed on the lense that there is a clouded section in the centre part and suspect this could be burnt.
is there a way to attempt to fix this without getting a new lense for the machine?

Thanks

What projector have you got?  If it still under warranty, sometimes you may get a lens replacement.  Many sub $10K projectors suffer from non uniform focus and sometimes it is a bad lens, but often the entire line have the same fault.  If your seeing softer parts of the picture and you can have the unit repaired or replaced, then do so.  If not, then you need to choose what is more important to you - a sharp centre or sharp edges.

The BenQ projectors seem to have a focus difference between left and right sides of the image, so you can have a sharp left to centre or a sharp right to centre but not both at the same time.   On actual video, it is not noticeable, but frustrating when viewing a test pattern or text.

[Yacano]

Thanks Mark,

I have a Benq MP515 DLP Projector. now 2 years old, on it's second bulb... So do you think this is a design flaw with the focus from Benq?

I was actually looking into upgrading to a Benq MX511 - 3D ready projector because it has HDMI input to try and get clearer text, but I'm not sure if this machine would have the same issue with focus and I can not find any reviews on this product.

[709er]

Has anybody used the Disney WOW disc to help calibrate their projectors?
Pros? Cons?
Any feedback would be appreciated.

[:)]

709er, on 10 January 2012 - 06:16 PM, said:

Has anybody used the Disney WOW disc to help calibrate their projectors?
Pros? Cons?
Any feedback would be appreciated.

709, have only used for checking white purity.

with friend helping me with calibration we used spears and munsil for brightness, contrast and sharpness. and pj was spot on on default settings. rest of calibration was with curt palm software which came with his meter.

[709er]

:), on 10 January 2012 - 06:25 PM, said:

709, have only used for checking white purity.

with friend helping me with calibration we used spears and munsil for brightness, contrast and sharpness. and pj was spot on on default settings. rest of calibration was with curt palm software which came with his meter.

Thanks for that.
After fiddling around today and doing side by side comparisons with my old (Sanyo Z2000) PJ, and noticing that the whites on the Pana 7000 seemed slightly bluish in comparison, I am inspired to spin up the "wow" disc, and take it through it's paces.
I easily removed the slightly bluish tint, but there is such a multitude of settings and combinations, I thought that I should check out somebody else's math!

[MarkTecher]

Yacano, on 09 January 2012 - 01:37 PM, said:

Thanks Mark,

I have a Benq MP515 DLP Projector. now 2 years old, on it's second bulb... So do you think this is a design flaw with the focus from Benq?

Sadly yes.  If you look at the history of the BenQ projectors going back to 8720 (720P) the units were expensive with full electric zoom and focus and really good optics.  As they progressed to 1080, the cost was still high and allot of that cost was the optics used in the units at the time of W9000 and W10000.  Suddenly the W5000 and W20000 are released at half the retial price iof the previous models.  How?  They lost some of the electronics (zoom/focus went manual) and they changed to cheaper lenses.  The PQ dropped as a result, but their sales went through the roof because they could now offer an affordable 1080 DLP.

Quote

I was actually looking into upgrading to a Benq MX511 - 3D ready projector because it has HDMI input to try and get clearer text, but I'm not sure if this machine would have the same issue with focus and I can not find any reviews on this product.

Even auditioning the projector yourself is no guarentee that the projector you buy will have a good lens.  I would still be using my older W5000 had it not developed a case of the dreaded vertical stripes.  I now own a W6000.  The W5000 I had was sharp, but the lens has a scratch on it that (program pending) was visible on screen.  I didn't exchange it simply because i was more concerned with getting a worse replacement.  I helped a forum member get his W5000 lens changed out unnder warranrty because it just would not focus any near as good as mine.

[MarkTecher]

709er, on 10 January 2012 - 06:16 PM, said:

Has anybody used the Disney WOW disc to help calibrate their projectors?
Pros? Cons?
Any feedback would be appreciated.

There are some good patterns on this disc and the disc is worth owning.  The point they make to set their disc apart from everone elses is the "level flash" where the producers claim (I got to meet one at CEDIA 2010) is to prevent "eye retention" where when looking at a static pattern one may lose the sense of where the level began when makinng the brightness/contrast adjustments.  The pattern will randomly "flash" at full intensity to show the difference between what you have set it at and where it was.  I found it a bit distracting.  The levels seem to be the same as those on the THX Calibrator disc which is really good if you can find one.

[Yacano]

MarkTecher, on 10 January 2012 - 09:09 PM, said:

Sadly yes.  If you look at the history of the BenQ projectors going back to 8720 (720P) the units were expensive with full electric zoom and focus and really good optics.  As they progressed to 1080, the cost was still high and allot of that cost was the optics used in the units at the time of W9000 and W10000.  Suddenly the W5000 and W20000 are released at half the retial price iof the previous models.  How?  They lost some of the electronics (zoom/focus went manual) and they changed to cheaper lenses.  The PQ dropped as a result, but their sales went through the roof because they could now offer an affordable 1080 DLP.



Even auditioning the projector yourself is no guarentee that the projector you buy will have a good lens.  I would still be using my older W5000 had it not developed a case of the dreaded vertical stripes.  I now own a W6000.  The W5000 I had was sharp, but the lens has a scratch on it that (program pending) was visible on screen.  I didn't exchange it simply because i was more concerned with getting a worse replacement.  I helped a forum member get his W5000 lens changed out unnder warranrty because it just would not focus any near as good as mine.

Thanks Mark,

RE: Benq W6000, I would love to get my hands on one of these, it's features look amazing but I'm kind of not sold on the lamp life of 3000 hrs on Eco mode at a cost of $450 - $500 for the bulb, why is the bulb so costly when it's only 2500 lumens... *stares* ...If mankind was at the point where we could revolutionise the humble bulb it would be more economical.

[Yacano]

...So can I put the question out there instead of trawling the internet looking at reviews.... I challege you all with this this question!!

What is the best projector on the market that has the following?

1. Unit cost is under $1000
2. has HDMI / VGA connections
3. provides sharp text on the "whole" screen via a PC connection
4. has a lamp replacement cost under $300
5. has a lamp life of around 4000 - 6000 hrs

Could this be like trying to find the perfect man or woman? ...There's too many shonky Projectors out there.