8mm Forum: screen size please

This is topic screen size please in forum 16mm Forum at 8mm Forum.

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Posted by Mark Todd (Member # 96) on February 26, 2006, 09:55 AM:

Hi I wonder if someone could please tell me what size picture a 20mm lens on 16mm will give at 10-12 feet distance from the screen.
Many thanks Mark.

Posted by Bob Pucci (Member # 8) on February 26, 2006, 04:01 PM:

Hi Mark Don't know if this will help but try this site.

http://www.paulivester.com/films/projector/throw.htm

Posted by Mark Todd (Member # 96) on February 28, 2006, 02:34 PM:

Thanks Bob had ago at working it out frm there, be great if someone had chart for the 20mm, looking at thats as best I can I`d say its about where I want it.

Best Mark.

Posted by David Park (Member # 123) on March 05, 2006, 03:10 AM:

Takeing your lens to be 3/4"
At 10' screen width approx 5 ft
At 12' it would be approx 6 ft.

I have used a formula in a B&H user manual
I give it here so you can check my maths.

Screen width (ft) = 0.38 X projection distance (ft) then divide this by focal length (inches)

I also have another manual giveing it in metric.

Width (Meters) = Distance (meters) X 9.65 then divide this by focal length (mm)

Trust this helps, let us know how you go on.

Posted by Mark Todd (Member # 96) on March 05, 2006, 07:38 AM:

Thanks David, very handy indeed, my screen at present is 5,5 feet and about 11 feet give or take so sounds about right.
Best Mark.

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