[TheaterMaster]

For the moment my brain is at super saturate and I'm a bit confused by the calculator on PJ Central. When switching between 16:9 & 2.39:1 the throw range is longer, I assume this is not using an anamorphic lens? When using a CIH anamorphic lens setup the throw range for 2.39:1 would be the same as that of the 16:9 w/out?


Also in this particular installation we are just about at the minimum throw and according to the Panamorph site the UH480 lens will work but needs a curved screen. Looking at the Schneider Cine-Digitar Anamorphic 1.33x M Lens it appears that this would also be an option but its not clear to me and if it is applicable:

1. It would also require a curved screen?

2. Is it a better optic than the Panamorph?


Thanks

 

[stanger89]



Quote:
Originally Posted by TheaterMaster /forum/post/17004190


For the moment my brain is at super saturate and I'm a bit confused by the calculator on PJ Central. When switching between 16:9 & 2.39:1 the throw range is longer, I assume this is not using an anamorphic lens? When using a CIH anamorphic lens setup the throw range for 2.39:1 would be the same as that of the 16:9 w/out?

That's what I figured that calculator would end up doing. All their calculator does in 2.39:1 mode is calculates for the 2.39:1 portion of a 16:9 screen with no lens.


Yes, if you're using a Horizontal Expansion lens, you use the 16:9 throw in all your calculations.

Quote:
Also in this particular installation we are just about at the minimum throw and according to the Panamorph site the UH480 lens will work but needs a curved screen. Looking at the Schneider Cine-Digitar Anamorphic 1.33x M Lens it appears that this would also be an option but its not clear to me and if it is applicable:

1. It would also require a curved screen?

2. Is it a better optic than the Panamorph?


Thanks

Any anamorphic lens "requires" a curved screen. That is to say all anamorphic lenses (HE ones) produce pincushion that can only be corrected with a curved screen.


The issue is if the pincushion is significant enough for you to decide it needs a curved screen. Shorter throws produce more pincushion than longer throws.


Further, shorter throws require larger lenses because the light beam is bigger.


As far as Schneider vs Panamorph, a cylindrical lens will usually give you more options for adjusting to perfection than a prism lens, whether that ability is worth the price differential is up to you.


From what I know of the Schneider, I think it would be a tight fit at minimum throw, I think it's on the smaller side, size wise.

 

[mtbdudex]

Not sure if this will help or confuse you.


Taking the data in this chart (VW50/60/70 same data I believe):

I made these graphs in Excel to help visualize the parameters of throw distance vs screen size vs throw ratio:

I uploaded the excel file, you can modify for your situation.

Good luck.


btw, my screen is curved, though many people I know don't have a curved screen with a-lens.

My advice - try your situation flat on painted wall(simple primed white just for evaluation) first and see if it's acceptable to you first before going curved.

 

SonyVPL-VW60 LensAnalysis.xls.zip 11.6064453125k . file

 

[TheaterMaster]

Thank you stanger89 & mtbdudex, I have been off the forum for a few days, dealing w/ a computer virus, MICROSOFT!!!

Anyway I will have to reread and digest your posts to see what I can make of them.


Thanks again,

Mark aka Toys4Boys


"One way or another this darkness got to give."

 

[TheaterMaster]

After a quick read through a question comes to mind re. the throw range. If it is 10' 3" to the Sony lens to get a 16:9 image about 90" W x about 50" H when I add the anamorphic lens does that mean my throw range is reduced by the depth of the anamorphic lens?

 

[mtbdudex]



Quote:
Originally Posted by TheaterMaster /forum/post/17033314


After a quick read through a question comes to mind re. the throw range. If it is 10' 3" to the Sony lens to get a 16:9 image about 90" W x about 50" H when I add the anamorphic lens does that mean my throw range is reduced by the depth of the anamorphic lens?

throw ratio = image distance divided by pre-lens image width


you have 123 pj to screen /90 screen width = 1.3666, seems you are below the min ratio recommend by Panamorph (1.4 theirs)
http://www.panamorph.com/ModelUH480.html


if you subtract say 6"for a-lens 117/90 = 1.3, but everywhere I've read it's all pre-lens measurements for both.


AussieBob/others??

 

[syncguy]

As I understand throw ratio = pre-lens image distance divided by pre-lens image width


In this case it is 1.37. Probably this is in the short side for any anamorphic lens. The issues will be pin cushion, geometric distortion, chromatic aberration and uneven focus (centre and edge). I do not think Schneider, ISCO or Panamorph have any correction for pin cushion, geometric distortion or uneven focus (centre and edge) which could occur at this throw ratio. All these lenses have correction for chromatic aberration. One advantage of ISCO and Schneider is the ability to remove astigmatism via continues adjustment where Panamorph 480 uses corrective lenses to remove astigmatism which should be tailored for a particular throw ratio. Astigmatism is the inability to achieve simultaneous sharp focus on both vertical and horizontal axis. I am not sure whether astigmatism correction would be effective for a throw ratio as low as 1.37.


Although the throw ratio is low, I guess, the picture will be okay with masking - but I am not sure.


This is my understanding. Someone like Aussie Bob would be able to given an in depth analysis of this subject.


Based on my experience, I should add that Panamorph 480 is a brilliant anamorphic lens with ability to accept large beams. It produces an excellent picture with pixel perfect clarity and definition.

 

[CAVX]



Quote:
Originally Posted by syncguy /forum/post/17093469


As I understand throw ratio = pre-lens image distance divided by pre-lens image width

Correct or Scope Screen Width x 0.75 x TR.


Lets say that the screen is 50" tall or 118.5" wide (2.37:1) and the desired TR is 2.0.


118.5 x 0.75 x 2.0 = 177.75


177.75" is the distance needed between the screen's fabric and the projector's lens.

 

[CRGINC]

Mark,


I believe the VPL-VW50, 60, 100 and 200 have much the same throw ratios. The newer Sony projectors like VPL-VW70 and 85 have shorter max throws. Also they appear to have a more recessed lens. On Prismasonic's website the calculator assumes all the Sony projectors have the same throw ranges and I don't think they do. In my system if I wanted to upgrade from my 50 I could use a 60, 100 or 200 but I would at or above the maximum throw range for the 70 or new 85. In fact Sony boasts that you can get a larger picture from a shorter distance. Just what cinemascope lovers need!

 

[CRGINC]



Quote:
Originally Posted by mtbdudex /forum/post/17010210


Not sure if this will help or confuse you.


Taking the data in this chart (VW50/60/70 same data I believe):

I made these graphs in Excel to help visualize the parameters of throw distance vs screen size vs throw ratio:

I uploaded the excel file, you can modify for your situation.

Good luck.


btw, my screen is curved, though many people I know don't have a curved screen with a-lens.

My advice - try your situation flat on painted wall(simple primed white just for evaluation) first and see if it's acceptable to you first before going curved.

Thanks Mike for your work. I mentioned in a later post that the I believe the newer Sony projectors have a shorter maximum throw for a given screen size. Just the wrong direction for adding a lens.