Should convergence rectangles be the same size?

Discussion in 'Archived Threads 2001-2004' started by Greg_Ritchie, Oct 12, 2002.

  1. Greg_Ritchie

    Greg_Ritchie Stunt Coordinator

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    Hi,
    I've been trying to diagnose what the problem is with the convergence I've done. I brought up the convergence grid and measured the distance between each of the grids. The distance horizontally (left to right) between the boxs seems to be close to the same all the way across. Vertically however the boxes are drastically different, they seem to be largest in the center and then taper off in size to the top and bottom of the screen. Is this correct? Could this account for my squarish, squishy picture? The boxes in the center are about 4cm tall whereas the ones close to the top or bottom shrink down to between 2.25-2.5cm. If anyone knows if this is a problem it would be a great help.

    Thanks,
    Greg
     
  2. Gregg Loewen

    Gregg Loewen Video Standards Instructor, THX Ltd.
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    Gregg Loewen
    hi Greg, you again?? lol [​IMG]
    Yes, on the Tosh all the boxes should be the same size
    Write down the geometry settings then adjust one at a time to see if your image can be adjusted for better linearity.
    Last resort, is using the template and adjusting each green line.
    Best of luck!
    Gregg
     
  3. Allan Jayne

    Allan Jayne Cinematographer

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  4. Greg_Ritchie

    Greg_Ritchie Stunt Coordinator

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    Hi Gregg,
    Thanks again for your help, I called the store and talked to the person I bought it from. I guess I move some of the lines out instead of in, effectively I squished everything at the bottom and top and stretched the center. It's quite an entertaining picture, I'm just glad there are people in the forum to help me. I'm sure after people read my problems they don't feel half as bad about their own mistakes.

    Greg
     
  5. Bill Slack

    Bill Slack Supporting Actor

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    Greg_R...
    It's an easy thing to overlook. I did it once, heck, the first time I did my HD input I accidentally used the FULL grid (since the set said it was in FULL) and my set has a separate scanrate for HD... That turned out nicely! [​IMG]
    I've done much worse than that... even recently:
    The last few days I noticed 'streaks' across bright portions of the screen. I've seen it before (not on this set) and have attributed it to a failing power supply. But I was pretty sure it was something I did as I had been screwing around a lot with the set lately (re-setting all 3 gray scale settings to be the same and calibrating the bright/cont/tint/color for the different scan-rates, and finally (!) making my LD player look it's best...)
    But as everyone says 'RIGHT DOWN YOUR ORIGINAL VALUES' -- including me... but I only right down the ones I'm playing with and occasionally even forget that or hit a wrong button.
    So, after a few minutes of playing with any electrical settings and the peak white level setting (not sure if that helped, but it was wrong) based on default settings I found on the web, all was good.
    I was quite worried about doing permanent damage to the set if I couldn't clear things up. One wonderful thing about by set is the fact it has separate settings for multiple scan rates. I generally teach myself about the set in HD mode, as I can deal with having that screwed up for a little while more more comfortably, and by switching to DVD mode and NOT seeing the same problem, I can safely assume that it's my fault, and try to fix it! [​IMG]
    I need to get Gregg (Loewen) there to help me with my geometry when he gets back. I simply can not get my HD input to be really satisfactory, and am not sure why... I have the grids and have tried strings, but 1-2mm is all it seems to take... Also, not having HD test patterns is a killer! You're lucky in that way since there aren't separate scan rates...
    I must say though, having the control (and knowledge...) to make all these changes on consumer sets is just fantastic. I'm a total hack at it though! [​IMG]
     

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