Quantcast

curved straight lines?

J

jasonb

Guest
Hi,

I have just finished watching indy jones and the temple of doom and noticed in some scenes walls and doors frames are not straight but curve into the screen at the sides of the shot. If the camera pans across the screen the verticals follow a ( | ) patern. This is very noticible in the apartment scene when indy is examining the first half of a tablet (marker) and in the outdoor scenes walking through a walkway of pillars. I noticed a similar thing with indoor scenes in pulp fiction and poltergeist (sky digital broadcast).

I then decided to try indy and pulp through my xbox connected to a 4:3 tv and even though the picture was heavily bordered I was surprised to see exactly the same distortions in exactly the same places.

Other dvds do not show any distortion and the THX Optimizer's grid shows the screen to be free of geometry problems in any ratio. So my question is, has anybody else noticed such things and is this normal? It seems very odd that the exact same effect is seen in totally different set-ups. So am I right in assuming it has something to do with how the scenes are shot?

Cheers for your time,

Jason.
 

Zacabeb

Novice Member
It might have been shot with a quite wide lens, producing that distortion. I haven't seen the movie in its OAR but only Pan & Scan *shudder*, so I don't remember seeing that, but it would not surprise me. I've seen it in a lot of other movies, especially ones shot with anamorphic lenses like Indy.
 

LV426

Administrator
Staff member
Yes - if your display devices are set up right then it's probably optical properties of the camera lens.

A word of caution, though.

Many CRTs suffer from an effect I know as voltage regulation bounce. Bounce - because it varies with screen brightness. On rapidly moving video (eg music videos) such things as logos can be seen to move around their corner of the screen - this is one symptom.

The THX optimiser grid is a dark image. It is quite poossible that the TV's geometry goes "off" when the image is brighter. It MAY be causing the effect you describe. It IS common on many CRTs although less so on really high end examples (like Loewe).

It is a design flaw - corners are cut in the power supply for the tube.

The only way to verify whether the lines IN THE FILM are truly straight is to vuiew it on a flat panel - LCD or Plasma - these are totally free of geometry and bounce errors.
 
J

jasonb

Guest
Hi Guys,

Thanks for the replys.

I think I know what you mean about the bounce effect Nigel and I don't think its that.

It appears then to be the result of the lens since I have recently been looking for screenshots of the above mentioned films and the bending can be seen in these as well.

I will have to stop looking for such things and enjoy the film instead.

cheers, Jason.
 
P

Paul Atreides

Guest
If it's not in the geometry test, it's definitely the source video.
 

LV426

Administrator
Staff member
Originally posted by Paul Atreides
If it's not in the geometry test, it's definitely the source video.
In this case, it probably IS in the source.

But as I say, with a CRT, correct geometry on a dark image does not necessarily mean correct geometry on a bright image.
 
P

Paul Atreides

Guest
Bright images do affect things, but for distortion on this scale there would have to be something seriously wrong with the electronics.

Do you have professional experience of CRT's?
 

LV426

Administrator
Staff member
Not professional. But I do speak from experience.
 

Similar threads

Top Bottom