LCD projectors/overscan? at DVinfo.net

Go Back   DV Info Net > The Tools of DV and HD Production > Open DV Discussion

Open DV Discussion
For topics which don't fit into any of the other categories.


Reply
 
Thread Tools Search this Thread
Old November 4th, 2002, 06:50 AM   #1
Regular Crew
 
Join Date: May 2002
Location: Finland
Posts: 103
LCD projectors/overscan?

How do the LCD projectors generally work compared to the overscanning of TV sets?

Do they have a similar effect or do they display more of the incoming picture ?
Jami Jokinen is offline   Reply With Quote
Old November 4th, 2002, 10:07 AM   #2
Major Player
 
Join Date: Sep 2002
Location: Belgium
Posts: 804
LCD and other pixel oriented displays, map and display by default the full image content. This is allways the case for computer images, and mostly true for video. One can of course allways suppress (blanking) the outer area's and futher fill the projected image using extra zooming or throw distance change, if "overscan" is needed. Large overscan (10%), like it was used in the past(and still is used to a lesser degree in TV) in order to compensate for ageing, mains voltage changes, signal tolerances...in the old days, is no longer existing. So, don't believe the people telling you that you will not see vignetting on yr TV or projector (even CRT) because of applied "overscan"...better verify first!
Andre De Clercq is offline   Reply With Quote
Old November 4th, 2002, 03:54 PM   #3
Trustee
 
Join Date: Mar 2002
Location: Ann Arbor, MI
Posts: 1,327
I have had mixed results. Usually you get the whole picture, but there are some projectors that act like a TV and crop your image. Some you can go in and keep them from cropping, some you can move around the crop area,
but the image is gonna get cropped.

My advice, if you are planning on renting a projector for a show, go to the
rental house well in advance and get a demo to make sure. Then
reserve THAT projector for your date(s).

PS Also ask them what happens if the bulb burns out? ;)
__________________
Jacques Mersereau
University of Michigan-Video Studio Manager
Jacques Mersereau is offline   Reply With Quote
Old November 4th, 2002, 06:33 PM   #4
Major Player
 
Join Date: Sep 2002
Location: Cupertino, California, USA
Posts: 301
I created a 10 minute video which I projected in front of 250 people via a digital projector. As I was creating the video I was worrying about the cropping that my camcorder was doing and wondering if the same amount of croppage would be shown when I projected it. I didn't have time to test it, so I just hoped for the best. After creating the whole video and showing it on the digital projector I learned the hard way that my projector did not crop my video. I had more showing than I wanted and some stuff was seen that wasn't supposed to be. I think that I was the only one who noticed it though. The average person doesn't really look for/see those kind of things. So, to answer your question, the projector I used showed all my video and did not crop it (unlike a TV). But I am sure that different projectors vary, so, if possible, you should do what Jacques said and test your projector before you project! Good luck!
__________________
Scott Silverman
Shining Star Digital Video Productions
Bay Area, CA
Scott Silverman is offline   Reply With Quote
Old November 5th, 2002, 03:07 AM   #5
Regular Crew
 
Join Date: May 2002
Location: Finland
Posts: 103
I'm actually finishing a project that will mostly be shown via different LCD-projectors (so testing one is not useful), and sometimes (rarely) on a TV set.

To me it's more important that everything is visible, not vice versa. That's why it seems that the smartest thing to do would be rendering the project with somewhat smaller picture than the full resolution would allow (adding some black on the sides).

What I might lose is some 40-50 pixels (PAL) in case of a 100% projector but on the other hand gain full control of the visual impression in case of a cropping device.

Whichever I choose might lead to unpleasant results. Still I'd rather choose the one that gives me full picture every time.
Jami Jokinen is offline   Reply With Quote
Old November 5th, 2002, 10:03 AM   #6
Trustee
 
Join Date: Mar 2002
Location: Ann Arbor, MI
Posts: 1,327
Good idea. You could also make several versions. One regular, one
slightly smaller image surrounded by black boarders, and another
even smaller image with large black boarders.

It is amazing how each TV/projector has its own crop factor.
__________________
Jacques Mersereau
University of Michigan-Video Studio Manager
Jacques Mersereau is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > Open DV Discussion

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 08:45 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network