1. Join Now

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

Lens Shift help

Discussion in 'Projectors, Screens & Video Processors' started by Oldgold, Mar 26, 2005.

  1. Oldgold

    Oldgold
    Active Member

    Joined:
    Feb 16, 2005
    Messages:
    169
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Ratings:
    +3
    Can someone please help me with a query over optical lens shift?

    I am currently saving for my first projector, which I am 90% certain will either be a Hitachi PJTX100 or Panasonic PTAE700. However, I have a query over the manual lens shift. My room is quite small, and quite narrow. I would be looking to project an image of around 78" wide (which is almost the room width (room width = 92")). However, due to the arrangement of the room, the PJ would ideally be located on the left of the room, which would mean it would face the gap between the right hand wall and the edge of the screen (cannot position screen dead centrally).

    My question is... would the lens shift on these machines be able to move the picture far enough to the right? Am I right in thinking that the lens shift works from the centre of the screen, so in this case I would need to move the screen more or less a whole half of the screen width (39")?

    Also , can you angle the projector to the screen from about 45 degrees or does it have to be flat on, 90 degrees?

    Would appreciate some advice.

    Thanks
     
  2. Sporran

    Sporran
    Active Member

    Joined:
    Dec 13, 2004
    Messages:
    1,486
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    66
    Location:
    Pembrokeshire, Wales
    Ratings:
    +135
    Hi Oldgold

    I cant comment on the PJs you mention but i got the HS50 and it is capable of 50% of the horizontal width, so if teh PJs you mention are similar this would work. Just need someone with these PJs to offer advice or have you checked the specs on their respective sites?

    As for the angle to the screen although 90 is best, you should have a feature called Keystone which allows for this positioning. It sort of tilts the screen so you get a square picture.

    If the PJs you mention are similar to the HS50 you shouldnt have any issues with your installation.
     
  3. PJTX100

    PJTX100
    Well-known Member

    Joined:
    Dec 21, 2004
    Messages:
    8,129
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    136
    Ratings:
    +562
    The TX can only do 25% (screen width) shift horizontally, but a whopping 75% vertically.

    To project at an angle as you describe you'd need horizontal keystone adjustment. Most machines have vertical keystone adjustment, but not many have horizontal I think.

    Anyway, to get the best PQ you want to avoid keystone adjustment and use as little lens shift as required. I too wanted to place the PJ offcentre but soon decided to adopt the central location, the lens shift is best used for fine tuning to your screen position...PJ
     
  4. Oldgold

    Oldgold
    Active Member

    Joined:
    Feb 16, 2005
    Messages:
    169
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Ratings:
    +3
    Thank you both for your responses.

    I have now discovered that the Sanyo Z3 has 50% horizontal lens shift, but I understand using the full lens shift can compromise picture quality. Oh well, I guess nothing is straight forward, will probably settle for placing PJ on a stand and just pulling it a couple of feet from wall when using it.

    So it's back to the Hitachi or Panasonic I reckon. On a separate note, PJTX100 (or any other Hitachi PJTX100 owner) do you ever watch football on your PJ. I wish to do this as well as watch movies, but the VB issue seems to be prevalent on the Panasonic when watching something with lots of the same colour, such as a football field, according to previous comments. Can any of these machine owners comment on their experiences of this?

    Many thanks
     
  5. explicitlyrics

    explicitlyrics
    Active Member

    Joined:
    Apr 26, 2003
    Messages:
    1,084
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    38
    Location:
    NW London
    Ratings:
    +9
    I have only ever noticed VB on my AE700 once and that was when I went hunting for it. The newest firmware (that you will probably have) has fixed most of the VB problems on the Panasonic unit that others have noticed. I try not to use significant lens shift and just wheel a stand into position at the start (takes 30secs). A good option in your case would be to get a wall mount (possibly designed for Hifi speakers or a TV) and pull it outwards and push it back against the wall for watching (the AE700 also only has 25% horiz shift btw).

    If you use fairly decent cables and a good source then most projectors will look good in most circumstances, i.e. these play a very significant part in picture quality compared to the actual projector.
     
  6. PJTX100

    PJTX100
    Well-known Member

    Joined:
    Dec 21, 2004
    Messages:
    8,129
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    136
    Ratings:
    +562
    I've never watched footy on the PJ, but that's not what shows VB - misty/smokey scenes are most likely to cause it.

    Arthur or (I believe) Master & Commander are 2 of the films you're most likely to see VB - there are others.

    You can get into the factory menu quite easily on the TX, and there are a few settings which affect VB - STRIPE is one of them, I had a fiddle with the STRIPE values the other night, you can actually see the VB appearing and disappearing as you adjust the settings... the Green settings seem to have the most effect... haven't seen any VB since I adjusted this...PJ
     
  7. shortneck

    shortneck
    Member

    Joined:
    Dec 30, 2004
    Messages:
    52
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    11
    Location:
    Athens
    Ratings:
    +12
    I am too a Hitachi PJTX100 owner and I watch both dvd movies and football on it (go Greece!).
    I have to say that even though the picture from tv isn't as good as dvds, watching big screen football in my living room is a very rewarding experience. And this is what my friends think too, that's why they visit me when there is a good game on!

    I haven't noticed VB but then again I haven't been looking for it...
     
  8. Oldgold

    Oldgold
    Active Member

    Joined:
    Feb 16, 2005
    Messages:
    169
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    18
    Ratings:
    +3
    Thanks for your comments, guys. Really appreciate it.

    Can you tell me if it is possible to use both the horizontal and vertical lens shift to the max at the same time on the Hitachi (I know this isn't possible on the Sanyo Z3). If so, does the PQ deteriorate an awful lot by using it, or is it just a negligible amount).
     
  9. PJTX100

    PJTX100
    Well-known Member

    Joined:
    Dec 21, 2004
    Messages:
    8,129
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    136
    Ratings:
    +562
    Yes I think you can use both to the max, at a guess you'll probably find it's watchable but there will be uneven focus ie one part of the screen in focus and another out of focus...PJ
     
  10. LV426

    LV426
    Administrator Staff Member

    Joined:
    Jul 14, 2000
    Messages:
    12,789
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    166
    Location:
    Somewhere in South Yorkshire
    Ratings:
    +4,975
    Use a ceiling mount. You know it makes sense.
     
  11. PJTX100

    PJTX100
    Well-known Member

    Joined:
    Dec 21, 2004
    Messages:
    8,129
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    136
    Ratings:
    +562
    Agree, that's what I did, but even with a ceiling mount you need some vertical lens shift...PJ
     

Share This Page

Loading...