Folks, I need a little help here.

This G70 is having a "flare problem" in the corners and sides. The dots everywhere are perfectly round (so I guess it is not a astig issue?) :confused:

The problem is that the dots in the corners and sides have flares. The end result looks like a comet. I have tried to depict that with this (crude) image I drew:

http://www.funkyhuman.com/hosted_images/side_flare_issue.gif

Seems like the electrons are behaving like a flashlight. When dead on center the flare is controlled by mag focus. But in the sides and corners the beam flares outwards.

I have adjusted the Mag Focus controls, the 2 P and 4 P ( AQP and DQP) controls.... but nothing helps for the corners and sides.

How to get them right?

You need to pick the right zone for the electronic astig. Sounds like you are only doing the centre.

No No... I have tried adjusting everything.. including the sides and corner zones..really! After all this time playing with CRT PJs I am not a newbie anymore ! :)

Note that only the center zone has the 2 and 4 pole adjustment. The sides and corners have only 2 pole adjustments.


You need to pick the right zone for the electronic astig. Sounds like you are only doing the centre.

My G70 has areas that flare can't be dialed out. At the most, the flare is 20% as bright as the dot, so you'll never see it in the picture. I wouldn't worry about it.

You have flare everywhere though, so yours may not be dialed in as good as it could be. Adjust the center with the dot pattern, then use the EM pattern for the perimeter. Crank the contrast wide open, adjust the for best focus and least amount of blooming (actually flare, but it looks like blooming). Also, as the the EM pattern gets in better focus, it gets dimmer, so look for that as well. This method is much easier than adjusting the perimeter with the dot pattern.

Raj,
Is the flare optical or electronic? If it is optical, you can move the projector back away from the screen and make it better. Sony provides a stop-down lens cap with a hole in it for adjusting electronic focus. Nobody I know uses it, but you can use it to determine if the problem is optical or electronic. I've got my PJ maxed out on raster usage and live with a bit softer corner focus than I'd like.

Raj,
I've got my PJ maxed out on raster usage and live with a bit softer corner focus than I'd like.

Same here.

It shouldn't bother you watching movies.

The corners on a Windows desktop will be soft though.

Same here.

It shouldn't bother you watching movies.

The corners on a Windows desktop will be soft though.

Ditto.
the old compromise between max image width vs shortcoming of the G70 LC's throw distance and lens characteristics.....

Double check the under/overfocus mechanically thou....instead of moving the actual projector, try the 'card' technique in the corners

Hmmm...
How do I determine if it is optical or electronic?
I guess I'd have to look into the lenses....right on the tube, right?

I'll do that ASAP and report.

Raj,
Is the flare optical or electronic? If it is optical, you can move the projector back away from the screen and make it better. Sony provides a stop-down lens cap with a hole in it for adjusting electronic focus. Nobody I know uses it, but you can use it to determine if the problem is optical or electronic. I've got my PJ maxed out on raster usage and live with a bit softer corner focus than I'd like.

Is this because the G70 has those cheap looking plastic lenses?

Even my lowly Ampro 4200 had bettter focus in the corners!

After three CRT PJs and years of troubleshooting and tweaking .........these days..... I am REALLY inclined towards digitals.
I think I am burnt out.

Ditto.
the old compromise between max image width vs shortcoming of the G70 LC's throw distance and lens characteristics.....

Double check the under/overfocus mechanically thou....instead of moving the actual projector, try the 'card' technique in the corners

How many pages and how long can we drag out this thread only to give up at the very end :D

Is this because the G70 has those cheap looking plastic lenses?

Even my lowly Ampro 4200 had bettter focus in the corners!

After three CRT PJs and years of troubleshooting and tweaking .........these days..... I am REALLY inclined towards digitals.
I think I am burnt out.

If your Ampro 4200 has better focus in the corners, assuming there's nothing wrong with the projector, you're not setting it up right. :rolleyes:

The ONLY time any of the issues you describe should even come into play, is when you are utilizing a raster size all the way out to the left and right edge of the tube face. On a raster size set by Sony right out of the box, you can adjust the flare virtually perfect to the edge of the raster.


And yes, the all glass and aluminum lenses that came on early G70's were better, however, the carbon fiber lenses shouldn't be a problem.

If your Ampro 4200 has better focus in the corners, assuming there's nothing wrong with the projector, you're not setting it up right. :rolleyes:

The ONLY time any of the issues you describe should even come into play, is when you are utilizing a raster size all the way out to the left and right edge of the tube face. On a raster size set by Sony right out of the box, you can adjust the flare virtually perfect to the edge of the raster.


And yes, the all glass and aluminum lenses that came on early G70's were better, however, the carbon fiber lenses shouldn't be a problem.

Oh...My...God... Look who crawled out of the woodwork to get a AmPro dig in. :D
Brucie, how the hell are ya bud? It's been awful boaring around here without someone to bust my klinkers :p

Oh...My...God... Look who crawled out of the woodwork to get a AmPro dig in. :D
Brucie, how the hell are ya bud? It's been awful boaring around here without someone to bust my klinkers :p


Just when I thought it was safe to go back into the water....... :D

What the hell is with the price of oil, Boilerman? :p

Hmmm.....
I AM maximizing the image size all the way out to the left and right edge of the tube face (I have left around 7 to 10 mm blank). Isn't that the right thing to do?? :confused:

Why is this that the Sony G70 cant run its rasters bigger than the factory set ? :mad:

Is the situation the same with the G90? :(

One more thing I just noticed..........if I reduce the brightness / contrast to (say) around 20/ 20 the flare goes away and the dots or EM pattern is very sharp......all over the screen! (including the sides and corners.) :)

So I guess the PJ is losing focus at high contrast settings.....but only in the sides / corners!


If your Ampro 4200 has better focus in the corners, assuming there's nothing wrong with the projector, you're not setting it up right. :rolleyes:

The ONLY time any of the issues you describe should even come into play, is when you are utilizing a raster size all the way out to the left and right edge of the tube face. On a raster size set by Sony right out of the box, you can adjust the flare virtually perfect to the edge of the raster.


And yes, the all glass and aluminum lenses that came on early G70's were better, however, the carbon fiber lenses shouldn't be a problem.

Hmmm.....
I AM maximizing the image size all the way out to the left and right edge of the tube face (I have left around 7 to 10 mm blank). Isn't that the right thing to do?? :confused:

Why is this that the Sony G70 cant run its rasters bigger than the factory set ? :mad:

Is the situation the same with the G90? :(

One more thing I just noticed..........if I reduce the brightness / contrast to (say) around 20/ 20 the flare goes away and the dots or EM pattern is very sharp......all over the screen! (including the sides and corners.) :)

So I guess the PJ is losing focus at high contrast settings.....but only in the sides / corners!

Yes, you CAN enlarge the raster out to 7-10mm from the edge, HOWEVER, it will be at the expense of "some" edge problems. Part of the reason is because the diameter LC lenses that Sony chose to use on the G70. The HD10 type LC lens that is used on 8" and 9" Marquees for instance, the diameter is better able to handle increased raster sizes. They even tailor the lenses on many projectors, like in the case of HD10 (small) GT17 (medium) and GT26 (large) etc. screens.

What you are seeing, when you reduce the brightness, is the reason that Sony suppled the lens cap with the pin hole in it. It was to enable the flare to ve setup at a HIGH contrast setting while allowing you to SEE the adjustment easily, which is VERY hard to do if you have a high contrast setting.

Like anything else, having experience with the particular projector you're setting up will ALWAYS result in a better resullt. If you got the projecotr used, you don't know where the settings are at to begin with. Once the tubes are changed, doing a reset mean NOTHING, because they were done at the factory for the ORIGINAL tubes and their particular setting.

In any case, you MUST foloow the factory manual to get a proper result. For instance, before you adjust the mechanical neck magnet, you must first set the 2 and 4 pole electronic adjustment settings to 128. When all these procedures are followed, without skipping any, the G70 can be setup and display one of the best pictures around. ........I sure there are other G70 owners that will confirm what I'm saying......right Phil, Tom, or Mark?

Not me man. While I'd like to pickup a G70 chassis one day, out of interest (I have XG tubes that will work), I'm an XG LC owner, not a G70.

I helped set one up a couple of times - so now I'm an "expert" ;)

Tricky projector to set up I found. Couldn't understand the whole Raster/Image/Pattern relationship/controls (or lack of them).

Not me man. While I'd like to pickup a G70 chassis one day, out of interest (I have XG tubes that will work), I'm an XG LC owner, not a G70.

I helped set one up a couple of times - so now I'm an "expert" ;)

Tricky projector to set up I found. Couldn't understand the whole Raster/Image/Pattern relationship/controls (or lack of them).

Yes it can be tricky if you're NEW to it, but, I thought at this point that you were experienced with it. ;)

Okay.....excluding Mark. :rolleyes:

Interesting… I was about to drop (not literally) my G70 from the ceiling and move it 8” closer to the screen in order to max the rasters.
I took what the latest version of PJCalc said when fitting it to the ceiling as gospel. So at the moment I have the G70 set up for a 2500mm wide 16x9 screen where the distance from the screen surface to the front of the G70 lenses (the point to be measured from as per PJCalc) is 3330mm. I had intended to move it 200mm closer.
I’m looking for an excuse to leave it where it is!

What would the G70 Gurus out there suggest?

I dont have the special lens caps. Any place I can get them?
What do they look like?

Maybe I can make one?

I do have the regular lens caps.



What you are seeing, when you reduce the brightness, is the reason that Sony suppled the lens cap with the pin hole in it. It was to enable the flare to ve setup at a HIGH contrast setting while allowing you to SEE the adjustment easily, which is VERY hard to do if you have a high contrast setting.

I think I received one of these when I got one of my G70s – It’s a regular cap with a hole cut directly in the middle. From memory, the hole diameter is about 40mm.

Yes, echoing barcoed's question: where SHOULD you set it up? Should you maximize the rasters, or should you just follow the guidelines in PJcalc and/or the manuals?

Interesting… I was about to drop (not literally) my G70 from the ceiling and move it 8” closer to the screen in order to max the rasters.
I took what the latest version of PJCalc said when fitting it to the ceiling as gospel. So at the moment I have the G70 set up for a 2500mm wide 16x9 screen where the distance from the screen surface to the front of the G70 lenses (the point to be measured from as per PJCalc) is 3330mm. I had intended to move it 200mm closer.
I’m looking for an excuse to leave it where it is!

What would the G70 Gurus out there suggest?

DON'T use PJCalc as the gospel.....or your raster might be too small. ;)

It's fine to increase the raster size on a G70....just don't over do it. Unlike a Marquee, if you go all the way out to the sides, you won't get the best edge focus. In addition, you put a strain on the deflection board.

That said, the raster size on a new G70 out of the box is TOO SMALL. Although you'll get perfect edge focus, you'll burn-in an overly small raster.

I normnally adjust the raster size using the average resolution and refresh rate that will be used on the projector and then I set the distance to that.

I believe it usually works out to between 8-10% closer than PJCalc says.

Hi,

from what I see the flare is symmetrical all around.
That points to a very good electronic and tube neck setup and is probably as good as can be.

When nearing the extreme edges of the phosphor some compromises have to be made, only reduced contrast settings will reduce this problem.

The only other reason this might be a bigger problem than usual would be an extremely close projection distance, I managed to get this problem even worse with an NEC PG extra on a ca 60" wide temporary setup and full raster usage :)
But in those cases you do not let the flare disappear by the lowering the contrast, so I would say this is not the case here.

Oliver

I dont have the special lens caps. Any place I can get them?
What do they look like?

Maybe I can make one?

I do have the regular lens caps.

All you need to do to make the "special" lens cap is punch a hole in one of your G70 lens caps about 2mm.

I never use them to setup a G70. I setup the flare, etc. with the contrast at the level that will be used for the particular installation and make the adjustment just like you would on any other CRT projector. Once you get the hang of what to look for, you'll find that you can get it even better not using the cap. When setting the flare, don't forget to adjust the focus so you can see the bright center of the crosshatch/dot pattern. Watch out for the interaction between the settings. Until you get used to it, you can get lost in all the adjustments. ;)

What's really needed is a step by step manual. Maybe someday when I'm feeling better I can make one. The G70/G90 really have a great set of controls compared to most projectors, but Sony service and instruction manuals SUCK. The service manual has typos that they've never corrected and they can really screw you up. :mad:

Hi,

from what I see the flare is symmetrical all around.
That points to a very good electronic and tube neck setup and is probably as good as can be.

When nearing the extreme edges of the phosphor some compromises have to be made, only reduced contrast settings will reduce this problem.

The only other reason this might be a bigger problem than usual would be an extremely close projection distance, I managed to get this problem even worse with an NEC PG extra on a ca 60" wide temporary setup and full raster usage :)
But in those cases you do not let the flare disappear by the lowering the contrast, so I would say this is not the case here.

Oliver

If the focus and dot roundness is setup with a low contrast level, when the contrast is raised to the normal operating level (or higher), the focus and dot shape WILL change when the contrast is increased. That's the reason that Sony supplied the cap with the hole, so that the contrast could be increased while allowing you to see properly while making the adjustments. Any projector can be made to "appear" to have a sharper picture by putting an iris over the lens and stopping it down to increase the depth of focus.

It's the same reason that movies made years ago appear sharper and brighter than todays film (even though the lenses are much better today). Years ago they used VERY bright lighting in the studios, which allowed them to use a very slow lens stop, which in turn increased the depth of focus. It's the same trick that is used to improve the look of cheap lenses today.

If the focus and dot roundness is setup with a low contrast level, when the contrast is raised to the normal operating level (or higher), the focus and dot shape WILL change when the contrast is increased. That's the reason that Sony supplied the cap with the hole, so that the contrast could be increased while allowing you to see properly while making the adjustments.

I see what you mean and I agree but Rajdud IMO is thinking that his projector is behaving strange when in fact this phenomen seems to be perfectly normal to me.

Oliver

That's the reason that Sony supplied the cap with the hole, so that the contrast could be increased while allowing you to see properly while making the adjustments. Any projector can be made to "appear" to have a sharper picture by putting an iris over the lens and stopping it down to increase the depth of focus.But that only affects **optical** focus. Aren't we talking about magnetic flare?

Or are you saying the pinhole iris gets rid of optical focus errors from the edge of the lens, so you wouldn't see the flare when you get too close to the edge of the tube?

t's the same reason that movies made years ago appear sharper and brighter than todays film (even though the lenses are much better today). Years ago they used VERY bright lighting in the studios, which allowed them to use a very slow lens stop, which in turn increased the depth of focus. It's the same trick that is used to improve the look of cheap lenses today.Hey Bruce! Good to hear from you! I hope you're feeling better.

That's interesting. I've noticed that older black and white movies, and even modern films that use hard lighting (few and far between these days), the picture seemed sharper. I thought it was due to higher contrast edges created by back lighting, but better sharpness due to the lens being stopped down makes total sense.

I had a Barco 1200 9" PJ with the big Delta lenses. They were easy to focus, and corner focus was very good with little effort. I've always struggled to get good corner focus on my G70. I use to think the reason was I sucked at mechanical focus. The Barco made me realize how poor the G70 lens' edge focus is. I'd sure like to have a set of the glass lenses.

That said, as already mentioned in this thread, the only time I'm aware of my poor corner focus is on Windows desktop. I never notice it during a movie. There's nothing in the picture composition that draws you eyes to the corners. I know for a fact in painting and photography, if the viewer's eyes are drawn to the corners, you did a bad job. :eek:

I am getting confused on this too!

Which of these statements are true?

Statement #1
I (also) understand that the pinhole iris gets rid of optical focus issues and lens abberations at the edges of the image.

That means that IF the strange "flare" like thing I see is actually optical......with an iris in place......I should NOT see it......right?


Statement #2
The G70 cant have round dots (without magnetic flaring) on the sides / corners IF we maximize the rasters.......right?


Are Both True? :confused:



But that only affects **optical** focus. Aren't we talking about magnetic flare?

Or are you saying the pinhole iris gets rid of optical focus errors from the edge of the lens, so you wouldn't see the flare when you get too close to the edge of the tube?

I am getting confused on this too!

Which of these statements are true?

Statement #1
I (also) understand that the pinhole iris gets rid of optical focus issues and lens abberations at the edges of the image.

That means that IF the strange "flare" like thing I see is actually optical......with an iris in place......I should NOT see it......right?


Statement #2
The G70 cant have round dots (without magnetic flaring) on the sides / corners IF we maximize the rasters.......right?


Are Both True? :confused:

In #1, the pinhole iris doesn't get rid of optical focus issues, it just "appears" that way.

In #2, The G70 "should" be able to be setup perfectly... or virtually perfect, since nothing in life is perfect. HOWEVER, while you CAN enlarge the raster, if you make it TOO LARGE, you will start to see edge problems as a result of the G70 lense's rear element diameter size being on the small side with respect to the FULL tube face.

Other than as noted above, you should be able to adjust everything to be "perfect enough" so that anything that might not be perfect will not be able to be seen when viewing under normal circumstances.

Unless some adjustment isn't working, you (or somebody experienced with a G70)should be able to adjust it correctly, which should produce a great picture. :)

So I guess what I take away from this is: don't enlarge the raster all the way to the edge of the phosphor. Keep it maybe 5-7mm (??) away from the edge on both sides, and that will let you keep the edges/corners sharp. Might have other advantages too (less stress on circuits?), but you do lose a few lumens.

Right?

So I guess what I take away from this is: don't enlarge the raster all the way to the edge of the phosphor. Keep it maybe 5-7mm (??) away from the edge on both sides, and that will let you keep the edges/corners sharp. Might have other advantages too (less stress on circuits?), but you do lose a few lumens.

Right?


RIGHT! :eek:

Umm.....
I think it has to be more than 5-7 mm.

You NEVER run the raster/image all the way to the ends of the tube. That is like suicide! You have to leave 7-10 mm unused normally.

In this situation (with the G70) this has to be more than this.....I am not sure how much....maybe someone more experienced will have real numbers.

Then again....how do you measure that? With LC (especially with the lenses on) you can only guess :(

So I guess what I take away from this is: don't enlarge the raster all the way to the edge of the phosphor. Keep it maybe 5-7mm (??) away from the edge on both sides, and that will let you keep the edges/corners sharp. Might have other advantages too (less stress on circuits?), but you do lose a few lumens.

Right?

Simple: you take the lenses off. One of the first things I figured out with my G70 was how to defeat the lenses-off-power-off interlock. Turns out it's simple -- just ground the lead that normally hooks onto the spade bit on one corner of the lenses. Then you can pull the lenses for some proper raster centering & sizing without having to peer through the lenses and guess.

Hey man, don't be so dramatic ;) We can do this without numbers and calulations. Decrease the raster size a few clicks and see if your flare problem goes away. If not... try a few more clicks.

Bruce, glad to see you on the forum again. Thanks for sharing this information. This is a new one for me too. Does this same problem exist on the G90? Or is the lens size more appropriate on the G90?

-Mark

In this situation (with the G70) this has to be more than this.....I am not sure how much....maybe someone more experienced will have real numbers.

Then again....how do you measure that? With LC (especially with the lenses on) you can only guess :(

I use to push the raster very close to the edge. You end up using the extremes of the lenses that were never intended to be used. Not only is focus bad, the corners get distorted.

Over time, I've gradually moved my PJ farther back from the screen to reduce my picture size. Now I'm running the picture at least 15mm from the edge, maybe 20mm. It makes dialing in the geometry much easier and focus better. Whatever you give up resolving power is well worth it.

While maximizing phosphor usage has many positives, there are certainly some negatives about it.

I see what you mean and I agree but Rajdud IMO is thinking that his projector is behaving strange when in fact this phenomen seems to be perfectly normal to me.

OliverDon't know about other PJs, but judging from my experience with my G70, I agree.

Now I'm running the picture at least 15mm from the edge, maybe 20mm. !!! 20mm is about .75" -- that means you're not using 1.5" of the ~6.5" width of the tube!?

With 7mm spacing you lose 0.5" of the ~6.5" of tube width. Your image is 1" wider, let's say 6" instead of 5" as an approximation. That's a 20% increase in width, 44% increase in area. Which translates to a 44% increase in lumens. That seems like an awful cost to pay for better corner focus...!

I'm not sure it's that much, but it's definitely more than it used to be. I'll look at it today when I get a chance. It wasn't really for corner focus, which is still not that good. It was to improve geometry.

Hey man, don't be so dramatic ;) We can do this without numbers and calulations. Decrease the raster size a few clicks and see if your flare problem goes away. If not... try a few more clicks.

Right! :p


Bruce, glad to see you on the forum again. Thanks for sharing this information. This is a new one for me too. Does this same problem exist on the G90? Or is the lens size more appropriate on the G90?

-Mark

It shouldn't be much of a problem on the G90 since they use the same lens element size and Panasonic tube face size like all the other 9" projectors. However, you will always introduce slight edge focus problems when you get right up there near the tube frame edge.

!!! 20mm is about .75" -- that means you're not using 1.5" of the ~6.5" width of the tube!?

With 7mm spacing you lose 0.5" of the ~6.5" of tube width. Your image is 1" wider, let's say 6" instead of 5" as an approximation. That's a 20% increase in width, 44% increase in area. Which translates to a 44% increase in lumens. That seems like an awful cost to pay for better corner focus...!

That might all be true if you could calculate lumens like that, however, I just read the light output on my Minolta meter and can tell you for certain that increasing the raster on the tubes face doesn't translate into an increase in light output like you're calculating it.

P.S. .....and as for resolution, even if the increased raster size should theoretically result in an increase in resolution, it can't be seen with the human eye, so I don't think squeezing the last mm out of the tube face area is worth the other problems that result.

Boy, I don't understand HOW it wouldn't increase the light output. You have more square mm of raster projecting onto the same screen area. Assuming the projector keeps the illumination per square mm at the same level, the light level HAS to go up.

You DID move the projector forward when you did this test, so you were still projecting on the same size screen?

With more raster area projecting onto the same screen area, you have to get either more light (if the raster brightness stays the same) or less phosphor wear (if the tube brightness goes down so the screen brightness stays the same). Can't work any other way, unless I'm more confused than usual...

Boy, I don't understand HOW it wouldn't increase the light output. You have more square mm of raster projecting onto the same screen area. Assuming the projector keeps the illumination per square mm at the same level, the light level HAS to go up.

You DID move the projector forward when you did this test, so you were still projecting on the same size screen?

With more raster area projecting onto the same screen area, you have to get either more light (if the raster brightness stays the same) or less phosphor wear (if the tube brightness goes down so the screen brightness stays the same). Can't work any other way, unless I'm more confused than usual...

I didn't say there's NO increase, however, you're calculating it as if it a linear formula, but it's not. ;)

The other factor to consider is that *for a constant screen size*, setups using more of the tube face will necessarily have the projector mounted closer to the screen than setups using less of the tube face.

Merely changing the raster size and testing at the same screen distance isn't telling you the whole story with respect to the illumination hitting the screen in the final setup.

The other factor to consider is that *for a constant screen size*, setups using more of the tube face will necessarily have the projector mounted closer to the screen than setups using less of the tube face.

Merely changing the raster size and testing at the same screen distance isn't telling you the whole story with respect to the illumination hitting the screen in the final setup.

Yes, that goes without saying. It's just that if for instance, if you were using a 2" square area of the tube face and then enlarged it to a 4" square area (allowing for the SAME picture size) it won't result in a doubling of the light output as though it was a linear formula.

Why not? Are you assuming the drive circuitry hits its current limit and the phosphor output drops off?

If you have 2 square inches emitting X lumens (or whatever is the correct unit) per square inch, and 4 square inches also emitting X lumens per square inch, the second case is emitting twice as many lumens. Twice as many lumens spread out onto the same size of screen will result in double the foot-Lambert reading. (ftL = lumens / area)

So assuming the illuminance of the phosphor stays the same, how could increasing the phosphor area by X **NOT** increase the resulting ftL by X !??