Projector question for Clare

[matengawhat]

I was just wondering whats best to turn all zoom off on your projector and move it as far away from the sreen as possible to get the desired image size or to turn the zoom on to full and move the protector as close to the screen as possible so the light has less distance to travel or whether it really makes no difference.

i will try but that involves quite a bit or reorganising!

with thanks

 

[Andrew Everard]

matengawhat:I was just wondering whats best to turn all zoom off on your projector and move it as far away from the sreen as possible to get the desired image size or to turn the zoom on to full and move the protector as close to the screen as possible so the light has less distance to travel or whether it really makes no difference.

i will try but that involves quite a bit or reorganising!

Not quite sure I follow the logic, but I'd always use a projector as close as possible to the screen to minimise light loss. That's what my distant experience in stage lighting tells me.

But then my experience in photographic fields suggests that zoom lenses tend to perform less well at the extremes of their range, so maybe a projection distance that sets the zoom at around midrange is best.

 

[matengawhat]

Andrew Everard:
matengawhat:I was just wondering whats best to turn all zoom off on your projector and move it as far away from the sreen as possible to get the desired image size or to turn the zoom on to full and move the protector as close to the screen as possible so the light has less distance to travel or whether it really makes no difference.

i will try but that involves quite a bit or reorganising!

Not quite sure I follow the logic, but I'd always use a projector as close as possible to the screen to minimise light loss. That's what my distant experience in stage lighting tells me.

But then my experience in photographic fields suggests that zoom lenses tend to perform less well at the extremes of their range, so maybe a projection distance that sets the zoom at around midrange is best.

but is there any degredation in the picture by turnng the zoom on to full to get the projector closer to the screen?

 

[Clare Newsome]

There's no one answer to that, as it depends so much on the projector and room concerned!

The light reaching the projector screen halves when you double the distance - that's no problem if you've a powerful projector with a high lumens rating, but can become an issue with lower-powered projectors, which may be happier nearer the screen (eg on coffee table firing upwards).

I've used projectors both ways, depending on room set up and projector concerned. As Gary Mardell said in another projector thread, the screen/room/projector equation is a key one - there needs to be the right balance, just as in your home cinema system itself.

 

[Andrew Everard]

Clare Newsome:
There's no one answer to that, as it depends so much on the projector and room concerned!

And the quality of the lens, but with the majority of projectors that's tricky to assess without tearing the projector apart.

 

[Andrew Everard]

matengawhat:

but is there any degredation in the picture by turnng the zoom on to full to get the projector closer to the screen?

You mean setting the zoom to minimum? In my (photgraphic) experience, zoom lenses tend to be a bit touch and go at their widest angle setting, and aberrations tend to set in.

 

[matengawhat]

i meant setting zoom to its maximum so the projector can be placed closer to the screen

but guess your prob right at going for the mid range

 

[Anonymous]

There are tradeoffs in terms of throw distance and lens quality.

Typically lens zoom position and lens shift position moves the image outside the lens performance sweet spot. The image is moved from lens center by using shift or the image is made bigger and uses more of the lens depending on zoom position. This can introduce artefacts such as chromatic aberration depending on the lens quality. It's much more expensive to have a lens that provides the same image performance over a greater range of the lens area. Hence the smaller the area used the better.

Dasp

 

[Andrew Everard]

matengawhat:i meant setting zoom to its maximum so the projector can be placed closer to the screen

but guess your prob right at going for the mid range

Ah right, I think we're getting confused in terminology. That situation would actually be with the zoom at minimum - ie giving the least magnification.

 

[matengawhat]

cheers everyone

 

[Anonymous]

Hi

A quick question regarding my Panasonic PT-AE2000 projector set up. ÿI have it set up about 14 feet from my screen and for the most part the picture is brilliant through Bluray.

I've noticed that the left side of the projected picture is slightly out of focus compared to the right and no matter what i do adjustments wise i can't get full focus like the right side. ÿIs this a lens problem?

Secondly, white text on a black background reveals 2 pixels worth of purple/red colouring above the text and green colouring below it. Is this RGB panel misalignment? ÿÿ

The projector is still under warranty.

Thanks

Raihanÿ

 

[Anonymous]

It sounds like a combination of chromatic aberration (focus, colour fringes) and/or panel misconvergence.

You need to check what is within tolerance with Panasonic as with some manufacturer up to two pixels of MC is deemed in spec and not covered by warranty.

Dasp

 

[Anonymous]

Thanks for the advice. I contacted Panasonic Projectors and they feel that there is something wrong with it from the description i gave. So they're sending someone round tomorrow to pick it up for a diagnostics and repair/adjustment.

Thanks again,

Raihan