Blue Focus on BG 808

[audimushroom]

I've been working on another setup of my BG 808, checked mech setup etc and I have my best geometry yet, 1st time I've got it square all round, so it does prove that practice really does help, if its not right do it again...

Anyhow it would be great except that the Blue focus in the top right corner is really off and adjustments don't improve it much.
Convergence at centre is great for all three.
The red on green is great but when I do the blue on green the right side and in particular the top right corner is fuzzy so blue bleeds over the green line rather than sit on top.
I also get a blue shift of colour on the right side of the image on a white screen(100ire from Lumagen) which also shows a blue patch in the top right corner and to a lesser extent the top left corner. I guess this is because of the soft focus leading to the bleed over the green?

I am wondering if there is an obvious error here ? or do I have a fault?

I did wait an hour to warmup before setting up so I know its not a warmup issue...

Resolution is 720p at 72hz from the Lumagen, nice smooth pans on motion...

HD-144 lenses 92" 16:9 screen and the PJ is 2.8 metres from the screen

 

[Barcoing Mad]

Is it mechanical or magnetic focus which is off?

 

[audimushroom]

Is it mechanical or magnetic focus which is off?

It does not matter which I adjust its still fuzzy....

 

[barcoed]

I recently acquired a BD808 which had a fuzzy focus on all tubes – slackening and moving the focus coils fixed it.

 

[Alaric]

Hi There,

Is this just one corner or all over fuzz....The tube focusing/astig etc would only work if an all over fuzzy picture.

I can't recall if i did a tube focus on that, though things can slip/drift in movement and interestingly the earths magnetic field also affects from what i've read

If its a corner i'd suspect the lens flapping ???

However i would also say that the edges are never as sharp as the centre, but the should all be uniform.

Blue is always the dimmest and least sharp. Red always seems to be sharpest, green is medium, blue is often soft and even then is also defocused to increase the brightness in a lot of cases. Blues suck

cya,
Lee

 

[Barcoing Mad]

If you look at your tube through the lens, is the image sharp over the area of the phosphour? (back off contrast or wear sunglasses).

 

[audimushroom]

If you look at your tube through the lens, is the image sharp over the area of the phosphour? (back off contrast or wear sunglasses).

Yes the Image is sharp when looking at the tube face and its not close to the edge...

 

[audimushroom]

Hi There,

Is this just one corner or all over fuzz....The tube focusing/astig etc would only work if an all over fuzzy picture

.

It is mostly the corner top right but there is blue tinge to very right side aswell which also shows as less fuzzyness than the corner

If its a corner i'd suspect the lens flapping ???

Ok will try this a bit later once I have a bit of time...

However i would also say that the edges are never as sharp as the centre, but the should all be uniform.

Agreed it should be uniform

 

[audimushroom]

I have tried adjusting flapping but it is not much help although it has reduced the effect a bit.

See pics if they help?

 

[Mad Mr H]

HI,

It might help if you took pictures of the four corners and center of JUST the Blue.


My initial thought would be "lens flaping" - Sometimes known as Scheimpflug adjustment


IF the tube face is "perfect focus" then the issue MUST be in the optical path.

That gives the options of LENS or Scheimpflug.

Try turning the lens 180 deg if the focus issue moves then its that lens, Also try moving the green lens to the blue - again if the green is worse and blue better its that lens.

YES - it can be the lens , Several members here have noticed that of their three lens that one is better than the others and so usually put on green, next best on red, worst on blue.

HD8 revB replaced with HD8 rev A usually show an improvement in both focus and stability (due to temperature changes)

Looking at your picture I see the following - as you go towards the top right dots and grid are extended in a diagonal (from the center point) - although this does look like an astig issue, it is out by so much that I feel Scheimpflug has a part in this as well as astig.


There is a "dynamic astig" menu - check that is not set way off for that section of the grid (top right).


Does your "+" in the "intallation" setup blue on green meet up ???

Hope that is of help, I do feel I have only gone over ground covered by others.

Andy H.

 

[audimushroom]

Hi Andy

Thanks for the advice, I've some response now..

My initial thought would be "lens flaping" - Sometimes known as Scheimpflug adjustment

Yep I had done some work with these adjustments but did not seem to help however....

IF the tube face is "perfect focus" then the issue MUST be in the optical path.

That gives the options of LENS or Scheimpflug.

Try turning the lens 180 deg if the focus issue moves then its that lens, Also try moving the green lens to the blue - again if the green is worse and blue better its th at lens.
YES - it can be the lens , Several members here have noticed that of their three lens that one is better than the others and so usually put on green, next best on red, worst on blue.

HD8 revB replaced with HD8 rev A usually show an improvement in both focus and stability (due to temperature changes)

Ok makes sense if tube face is sharp then must be optical..
Well it was quite good but not perfect...
Hmm I guess with the colour filtered HD-144 I'm using that switching them is not an option...

Looking at your picture I see the following - as you go towards the top right dots and grid are extended in a diagonal (from the center point) - although this does look like an astig issue, it is out by so much that I feel Scheimpflug has a part in this as well as astig.


There is a "dynamic astig" menu - check that is not set way off for that section of the grid (top right).

OK so I have now checked the Dyn Astig and yes all 4 corners were out so have now adjusted all 3 guns and the dots are now round but the blue was out the most, then went on to adjust flapping and can now converge the corners nicely, still not quite as sharp as the centre but I know thats not possible.
When fed a picture source there has been quitre a sharpness improvement..

Does your "+" in the "intallation" setup blue on green meet up ???

Yes no probblem with that one...

However the colour shift is still there, more red on the left side and more blue on the right side, any ideas on that?

 

[Mad Mr H]

You can check the "Blue" lens on ANY other tube.........its NOT colour filtered so will work OK on any tube .


Re "More red on left, blue on right" - focus magnets need to be correctly setup.

THEN if you still have this issue you will need to adjust the way to do your conv. to minimise this effect.

ALSO you might want to look at a red on blue cross hatch - that often shows up issues you dont see with red/green & blue/green.

So overall the picture is much better now ???

 

[audimushroom]

You can check the "Blue" lens on ANY other tube.........its NOT colour filtered so will work OK on any tube .


Re "More red on left, blue on right" - focus magnets need to be correctly setup.

THEN if you still have this issue you will need to adjust the way to do your conv. to minimise this effect.

ALSO you might want to look at a red on blue cross hatch - that often shows up issues you dont see with red/green & blue/green.

So overall the picture is much better now ???

Yes overall the picture is much better, sharper, thank you

Hmm focus magnets how would I know if they wrongly set ?

I will check into the red/blue cross hatch, I guess for that I turn off the green and use an external pattern such as from the lumagen? or is there another way?

 

[audimushroom]

Hello

Ok more pics attached and further improvements
I have re-adjusted the electronic focus which has helped all round, further tweaks to Dyn astig

Still have a pink bias on the left and blue on the right(although it is reduced) and I have tried looking at red on blue and there is some misconvergence almost a line width in places, what does this mean?

I have checked and all the lights are out for G2...