AVS Forum banner
1 - 14 of 14 Posts

·
Registered
Joined
·
64 Posts
Discussion Starter · #1 ·
Just put up my UH480 tonight coupled with a SONY VW70 18 throw to a 144" width 2:35 screen. When the lens moves into place the image gets smeared and loses focus. Anyone ever experience this
 

·
Registered
Joined
·
8,958 Posts

Quote:
Originally Posted by Stizzi /forum/post/15490291


Just put up my UH480 tonight coupled with a SONY VW70 18 throw to a 144" width 2:35 screen. When the lens moves into place the image gets smeared and loses focus. Anyone ever experience this

Sound like you might need to change the corrective element. Look on their website and you will see 5 different options. A (the standard element) is from 14 to 17 feet, so at 18 feet, you may need to go to element B...


Mark
 

·
Registered
Joined
·
216 Posts
I am experiencing a similar issue with a UH380 but will post as a new thread so as not to hijack this thread.
 

·
Registered
Joined
·
8,958 Posts
For years we have been advised to calculate out our TRs by dividing the 16:9 width into the distance from the screen to the projector.


So based on 18' throw and 12' wide Scope screen, the TR is about 2.0 or 18 / 9. However, the same TR could mean that the projector and lens is either further away or closer based on screen sizes. An example is having a Scope screen of 14' (10.5 foot 16:9 portion) and to get a TR of 2.0 means the projector is now mounted at 21' back.


If we using the same lens and projector with a different (larger) screen, this is where the use of corrective elements could be confusing.


The prisms don't have a focal length, so without the corrective element, the prisms would work at pretty much any throw, however, the prisms would also introduce astigmatism which is what the corrective element is designed to remove.


The corrective elements DO have focal lengths and why Panamorph now offer 5 different versions (A to E) in approx 3' increments.


The standard model comes with A, but to use the lens with the examples I have outlined above, the corective element needs to be changed to one with a focal distance in the range your opeerating the lens at. Note that both examples are based on the same TR of 2.0, yet there is 3' different between the two projection distances, therefore you would need to have two different elements to make this work...


Mark
 

·
Registered
Joined
·
736 Posts
UH480 coupled with vw60 gives sharp focus at about 17' throw distance. There is some reduction in sharpness towards the edges, I think, due to the increased throw distance towards the edges of the flat screen. At 18', I expect to get a good sharp focus. It is worth checking with Panamorph.
 

·
Registered
Joined
·
8,958 Posts
double post...
 

·
Registered
Joined
·
8,958 Posts

Quote:
Originally Posted by syncguy /forum/post/15493739


UH480 coupled with vw60 gives sharp focus at about 17' throw distance. There is some reduction in sharpness towards the edges, I think, due to the increased throw distance towards the edges of the flat screen. At 18', I expect to get a good sharp focus. It is worth checking with Panamorph.
Quote:
Originally Posted by CAVX /forum/post/0


The corrective elements DO have focal lengths and why Panamorph now offer 5 different versions (A to E) in approx 3' increments.

So which element are you using, A B C D or E? You probably should be using B for 18'...


Mark
 

·
Registered
Joined
·
736 Posts

Quote:
Originally Posted by CAVX /forum/post/15493921


So which element are you using, A B C D or E? You probably should be using B for 18'...


Mark

I have the corrective lens came with the UH480. I expect it to be A. However, it could be B. Panamorph was aware of my throw distance at the time of the upgrade and also they new about the slight sharpness issue I had with my previous 380. Once upgraded to UH480, the improvement was significant. I was impressed.
 

·
Registered
Joined
·
64 Posts
Discussion Starter · #11 ·

Quote:
Originally Posted by cal87 /forum/post/15491164


Just a thought, but did you remove the plastic film over the lens?

Cal thank you.
Problem solved. Man do I get the jackass of the year award or what.
 

·
Scott Horton, techht.com
Joined
·
5,747 Posts
Back when Optoma released the H77 projector, it came witha translucent lens cover. It was surprising how many reported problems until the realized they had to take the lens cover off. So your error wasn't *that* bad - if it make you feel any better
 

·
Premium Member
Joined
·
1,288 Posts

Quote:
Originally Posted by Stizzi /forum/post/15494903


Cal thank you.
Problem solved. Man do I get the jackass of the year award or what.

Just take a wild guess as to how I knew that.
 

·
Registered
Joined
·
1,771 Posts

Quote:
Originally Posted by cal87 /forum/post/15495400


Just take a wild guess as to how I knew that.

.... and one more makes three! Very funny. When I got my lens I was pulling my hair out and spent almost a full weekend moving the projector back and forth to try to eliminate blur and smear. Oy!
 
1 - 14 of 14 Posts
Top