Curved screen -using zooming feature?

Discussion in 'Projectors, Screens & Video Processors' started by G70baby, Aug 23, 2012.

  1. G70baby

    G70baby
    Active Member

    Joined:
    Aug 19, 2012
    Messages:
    147
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    28
    Ratings:
    +55
    Greetings all. I'm new to the forum so I'm hoping I can get some good advice from those with more knowledge and experience. I have decided to upgrade my beloved Sony G70 projector. I've have decided on the JVC X70/RS55 as it's blacks are more than acceptable to me.
    I've been out of the game for decade now and on my return all I read about is cinemascope screens are the way to go. I'm sold on the idea but then read on about anamorphic lens which will take a little more convincing mainly because of the price of quality lens from Schneider and Isco :eek:. Living in London I haven't found one to see in action to determine if they are better than zooming but I haven't ruled it out.

    I want to get a curved screen to keep my options open in case I decide to get a anamorphic lens. My dilemma is will it work with the JVC zooming or are curve screens only to be used for anamorphic lens setups?

    Any help will be appreciated.:)
     
  2. Ideal AV

    Ideal AV
    Distinguished Member AVForums Sponsor

    Joined:
    Jan 12, 2011
    Messages:
    11,007
    Products Owned:
    2
    Products Wanted:
    0
    Trophy Points:
    166
    Location:
    Normanton
    Ratings:
    +6,385
    unless you are going to go with a very good cylindrical lens i`d say forget the curved screen and see how you go with the X70`s lens zoomed to fill your 2.35:1 flat screen

    Allan @ Ideal AV
     
  3. G70baby

    G70baby
    Active Member

    Joined:
    Aug 19, 2012
    Messages:
    147
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    28
    Ratings:
    +55
    Thanks for your response Allan. I'm considering a Schneider lens as they are highly regarded and I like the sliding device. But I don't want to spend all that money at once otherwise I won't be able to eat. I'm considering getting the projector and screen first and the lens at a much later date. Hence my question 'Can I zoom on a curved screen?
    Do I actually need a curved screen with a anamorphic lens? I vaguely remember reading you could get away with a flat screen and avoid the pin cushion effect if the throw was long enough. Any truth in this? And if so, what kind of throw are we talking about?
     
  4. jacked

    jacked
    Well-known Member

    Joined:
    Jan 7, 2004
    Messages:
    1,211
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    83
    Location:
    Bolton
    Ratings:
    +422
    I don`t have a curved screen and I`m no expert but I think if you are going to zoom you definitely don`t need a curved screen, it`s a waste of money.

    In fact I wouldn`t consider a curved screen at all, unless you`re going for the more entry-level prism lens`and have a very short throw ratio.

    Due to their nature, you will never have 100% geometry accuracy with an anamorphic lens but if you use a high-end cylindrical lens, like the Isco, Schneider or CAVX, you will get exceptional results and shouldn`t see any pincushioning unless the throw ratio is very small.

    The picture might bow on one side very slightly but you won`t notice whilst watching a film or this can be disguised by screen masking.

    I think the bigger lens` can handle a throw ratio down to about 1.6 without issues, if I remember rightly my throw ratio is approx 2.0 or just under.

    Due to a change of circumstances I might be looking at selling my CAVX MK4 lens and Cineslide.

    Dave
     
  5. G70baby

    G70baby
    Active Member

    Joined:
    Aug 19, 2012
    Messages:
    147
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    28
    Ratings:
    +55
    Thanks for your response Dave. I'm not up to scratch with throw distances but I intend to take a more hands on approach this time with the installation. How is the throw calculated? :confused: I saw this formula in another thread. throw distance in inches/screen height, multiplied by 0.5625 = throw ratio
    139/40 x .5625=1.95
    Any thoughts?
     
  6. Peter Parker

    Peter Parker
    Distinguished Member

    Joined:
    Apr 6, 2001
    Messages:
    13,820
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    166
    Location:
    UK.
    Ratings:
    +3,313
    As the others have said, if you don't have a lens and are zooming, you don't need a curved screen (a curved screen without a lens gives you barrel distortion). Even if you get a lens later, a flat screen will still be OK because you can overscan the image onto the screen border and hide the pincushion (that' what I did ). A curved screen is nice to have when you have a lens, but even then it might not perfectly match the curve of the pincushion because throw makes a difference in the amount of pincushion you get.

    I would get a flat screen and try zooming first before considering a lens or until you can get a demo and decide if eating is really something you need to do in the future :)

    The throw calc looks fine - it's what they use over on avs. Throw ratio is how wide the 16:9 part of your screen divided into how far back the pj is. With a lens you need at least 2:1 to minimise pincushion, but if you're zooming, it doesn't really matter.

    Gary
     
  7. G70baby

    G70baby
    Active Member

    Joined:
    Aug 19, 2012
    Messages:
    147
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    28
    Ratings:
    +55
    Thanks Gary. I've seen your name mentioned accompanied with plenty of praise. I'll stick with a flat screen. My rooms is 19ft 8in by 12ft so I'm hoping to get away with a flat screen 110" scope and minimum pin cushion from an anamorphic lens. I haven't worked out the throw but reading past threads suggest that pin cushion is less an issue the loner the throw.
    I got a great price on a Schneider medium lens so I'm seriously thinking of taking a leap of faith. It would have been easier to see Bin Laden in London than an Isco or Schneider lens:laugh:.
     
  8. KelvinS1965

    KelvinS1965
    Distinguished Member

    Joined:
    Jan 3, 2006
    Messages:
    17,027
    Products Owned:
    1
    Products Wanted:
    1
    Trophy Points:
    166
    Ratings:
    +7,900
    That's pretty similar setup to mine: My room is a fraction longer and my screen is 112" wide, but close enough if you are mounting the PJ at the back of the room. I used to have a JVC HD350 and an Isco II lens and at absolute minimum zoom, with the lens in place, my image slightly overspilt the sides of the screen (I used my Lumagen to 'trim' a tiny sliver of pixels rather than 'see' the overspill as my screen border isn't perfectly light absorbing). I would expect the latter JVC throw to be similar (though always the chance of a slight tolerance especially at the end stops of the zoom).

    I don't know how my Isco II would compare to the lenses you are considering, but I had only a tiny amount of pin cushion, so a curved screen (not pratical anyway as there is a window behind where the screen drops :D:D) wasn't necessary by any means.
     
    Last edited: Aug 27, 2012

Share This Page

Loading...
  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice