1. Join Now

    AVForums.com uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

My new H78 - Help with settings required.

Discussion in 'Projectors, Screens & Video Processors' started by Lobo, Aug 7, 2005.

  1. Lobo

    Lobo
    Active Member

    Joined:
    Feb 4, 2004
    Messages:
    219
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Ratings:
    +3
    Just picked up my H78DC3 unit through Joe Fernand (Media Factory). First of all, just like to say thanks to Joe for his excellent and very helpful levels of service and knowledge, both prior to purchase and now post-purchase. Highly recommended if anyone is looking to purchase one of these units (or probably any projection unit).

    My setup at the moment is very amateur while I get my kit together. Simply projecting onto a (slightly off white wall) with a picture approx 8ft wide. The room can be blocked of any external light, but the room itself has quite light walls. Im using a cheap DVD Pioneer DVD player at the moment with progressive scan component input.

    The picture Im getting is decent, however the colours, contrast etc is blatently wrong. With me being a total novice at this stuff (my first projector), I need a good deal of help getting this setup correctly.

    I know settings are totally individual to environment, source etc. However, would anybody be able to give me a starting point for setting contrast, brightness, RGB levels etc to get a better picture. I plan to invest in a Video Essentials DVD shortly.

    Any help would be appreciated.
     
  2. Gary Lightfoot

    Gary Lightfoot
    Distinguished Member

    Joined:
    Apr 6, 2001
    Messages:
    12,464
    Products Owned:
    1
    Products Wanted:
    1
    Trophy Points:
    166
    Location:
    Surrey. UK.
    Ratings:
    +2,114
    TV gamma 1, 2 or 3 give the best luminence curve for film, so use one of those. I think the colour temps are something like 4500, 6000 and 7500 but I can't really remember. Colour temp 2 was the closest to D65 of the 3 though IIRC. CT1 is too red and 3 too blue.

    Use DVE to set white and black levels, there is a sticky at the top of the page to help you set them.

    If the colours are that bad, you might need it to be colour calibrated by Gordon or someone. Give it at least 100hours before you do though to let the lamp settle in.

    Gary
     
  3. Gordon @ Convergent AV

    Gordon @ Convergent AV
    Distinguished Member AVForums Sponsor

    Joined:
    Jul 13, 2000
    Messages:
    14,011
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    166
    Location:
    Living in Surrey, covering UK!
    Ratings:
    +2,808
    GARY: The colour temp is dependant on sources I think. I was at a clients today doing a Lumagen DVI installation and calibration. With the Lumagens you can get them to auto calibrate their Analogue component inputs to be correct gamma and greyscale on input side from DVD player. By doing this you basically create a very accurate test pattern generator. With this clients H78 (brand new) on temp 2 it was not close to D65. It was around 8000K....The RGB was also not linear once 100ire was set to D65. We fixed that in the scaler though. Ended up with a nice looking image.....and I have to say that posterisation caused by temporal dithering was non existent on the test piece I use that usually floors all single chip DLP......good work Optoma!

    Gordon
     
  4. Gary Lightfoot

    Gary Lightfoot
    Distinguished Member

    Joined:
    Apr 6, 2001
    Messages:
    12,464
    Products Owned:
    1
    Products Wanted:
    1
    Trophy Points:
    166
    Location:
    Surrey. UK.
    Ratings:
    +2,114
    Hi Gordon,

    Thanks for that. It's been a while since I've fiddled around with the settings so my memory is pretty hazy. I'm pretty sure my CT2 was lower than 8000k though and it was slightly pink across the board. Maybe a new lamp is the difference?

    I think you're right about the inputs, but if you have various sources connected to the same input then it won't remember any settings changes for the different sources, IE PAL and NTSC black level settings from a multi-region DVD player. This may have been fixed in later models though and isn't a problem if you can set NTSC to output 0IRE for black.

    What do you mean about the RGB being non linear exactly? Did you set for maximum red contrast at 100 IRE and then bring green and blue to match, and then find that you couldn't get the lower IRES flat without effecting 100IRE? If that's what you mean then it rings a bell but I can't remember what the conditions were for it or how I fixed it (might have been on analogue inputs only). Would the gamma curve cause this? Using any gammas other than TV will give a hump at around 70/80IRE IIRC, which is why TV seems better as it's flatter - Gamma 1 gave a system gamma of around 2.26 and Gamma3 was 2.55 on mine. This was all via DVI from HTPC. Was this machine the newer DC3 version?

    I found that by using an FL-Day and a Skylight 1B together I could ramp up more green and blue to get 2707:1 CR. Originaly it was around 2400:1 but that was out of the box and not at D65 IIRC. Did you measure what you got with yours?

    How did you fix the RGB problem with the Lumagen? Was that via the gamma adjustments? Did you get it flat in the end?

    What was the torture test you use for posterisation? I use a combination of chapter 15 (IIRC) of U571 and a clip from a CGI movie called 'Reboot my two bobs' (from a guy over on avs) which highlights the panning artefact. There are others of course but I'd like to add yours to my little set of test clips if that's OK. :)

    Cheers,

    Gary.
     

Share This Page

Loading...