8mm Forum: Over Engineering???

This is topic Over Engineering??? in forum General Yak at 8mm Forum.

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Posted by Rob Young. (Member # 131) on September 27, 2012, 09:12 PM:

So was the idea of using a split glass "shield" for a halogen 12v 15w bulb just over-engineering from the likes of Elmo or not?

After all, what did it really protect in the end?

Posted by Steve Klare (Member # 12) on September 27, 2012, 11:05 PM:

The ones I've seen have a specific purpose: protecting the film when held in single frame mode. The heat of a projection lamp would melt the film in a few seconds without it. So going that way without one is basically fatal for the film.

Even my entry level Kodak Moviedeck (my first projector) has one that swings in and out of the path for showing stills, but to me this whole mode of operation makes a lot more sense for a machine geared towards home movies than one intended to show commercial sound films.

I've had a ST-1200HD for three years, and fortunately never got around to trying still mode before I learned my machine arrived without the shield.

Posted by Hugh Thompson Scott (Member # 2922) on September 28, 2012, 05:46 AM:

To my way of thinking,a little piece of glass isn't going to make
any difference to the brightness of the projected image,but does
protect that delicate film from heat.As I have already stated in a different thread,stopping extraneous light from the projector
gives that screen a helluva boost, as does having a high ceiling
where reflected light from the screen "washes out" and reduces
contrast.Under ideal conditions,and the use of a prime lens, it's
amazing what some of these projectors can achieve without any
further modifications.

Posted by Tom Photiou (Member # 130) on September 29, 2012, 04:10 PM:

i agree with Hugh on this, the simple slit glass, (and i have a brand new genuine Elmo split glass for when i need it should i get a 1200 withot one),is put there for a reason,removing it,in my opinion, would make virtually no difference in the light output. If this glass was tinted then that would be different but it is plain clear glass. Without it you wont be able to use still frame withiout damaging your film.

Posted by Paul Adsett (Member # 25) on September 29, 2012, 04:52 PM:

I agree, the glass is there for a reason. No one puts extra parts into a projector design unless it serves a useful purpose. Even my old Kodascope 50 (vintage 1936) has a centrifugal shutter which blocks the light from the film if the film is not running. But, on the other hand, who really needs still and reverse projection? As film collectors, I bet none of us ever use either of these features, but of course these machines were all marketed as recording machines which could lay down elaborate sound tracks, and for that you probably do need still and reverse capability.

Posted by Rob Young. (Member # 131) on September 30, 2012, 12:21 PM:

I agree in priciple guys, but whenever you engage still frame / stop / start on an ST, an addional heat sheild swings down into place to protect the frame in the gate; surely this is more than enough, hence, why need a permanent glass sheild when in running mode?

Surely this cannot offer more protection than the piece of perforated metal that drops into place...many projector designs used this without a glass filter and non of them were fatal to still frame??

I suppose, if you left the projector in still frame for a very long time maybe... [Confused]

Posted by Jon Addams (Member # 816) on October 01, 2012, 11:40 PM:

quote:
"I suppose, if you left the projector in still frame for a very long time maybe."

Jon

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