This is topic Lens Question - Bell & Howell in forum 16mm Forum at 8mm Forum.
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Posted by Brannon Carty (Member # 2582) on May 21, 2012, 07:10 PM:
I have a Bell & Howell Filmosound 500 16mm projector. I've read different lenses project bigger images, which is what I need. My current one produces rather small images.
Here is my current lens:
76mm (3in) f/1.6
What do you all recommend to get a bigger image?
Posted by Thor Andre Karlsen (Member # 3021) on May 22, 2012, 03:39 PM:
A 3" lens like that one will give a 15" wide picture at 10 feet, while a 2" lens would give a 23" picture, and a 1,5" lens will give a 30" picture.
The most common lens is usually the 2", the 3" and 1,5" is also quite common, 1" and 0,635" is a bit more unusual.
The "f/1.6" tells you how much light passes the lens, lower numbers are better, an f/1.2 lens is much better for example than a f/1.6, something to think about when buying a lens.
There are also zoom lenses!
Here are a chart for calculating the picture size for each lens size: http://paulivester.com/films/projector/throw.htm
Posted by Wayne Tuell (Member # 1689) on May 23, 2012, 08:40 PM:
Paul Ivester's chart is pretty good tool for getting in the ball park with a lens or lenses.
I may have a couple spare 2" lenses if that size fits your needs. Also, a 1.6 lens is good to have on hand if you have a dupe that is a bit washed out or tad bright in scenes. Less light = better image on screen for the rare occasion of a not so good print.
Posted by Bill Brandenstein (Member # 892) on May 24, 2012, 12:15 AM:
76mm = tiny image! I definitely have some 50mm spares if you don't, Wayne.
Of course, for an even bigger image, go with 32mm or any other shorter focal lenth. But those lenses are harder to find and have held their value better.
Posted by Pasquale DAlessio (Member # 2052) on May 24, 2012, 07:40 AM:
Thor
Great chart. Thanks for the link!
PatD
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