Focusing done properly

[Paul Adsett]

We've had many discussions about sloppy focusing systems on projectors, even the high end GS1200 has this issue. The general consensus seems to be that the common rotating snail cam engaging a pin on the side of the lens barrel is probably the worst possible design. and the much preferred and simpler approach of using an external thread on the lens barrel engaging a sprung ball on the lens mount is the best. Now look at the Beaulieu design, with a micrometer type adjustment of the lens and I think this must be the ultimate way to do it:

[Rob Young]

It is very good, Paul, but certainly on my 708el there can still be some degree of adjusting it throughout a reel. I'm guessing that even with the Beaulieu gate design, any slight degree of increasing bowing of the film as it runs will just nudge the image out of focus ever so slightly. So even though the lens remains exactly where you focused it at the start, it'll sometimes still need just a minor tweak now and again as the film runs.

[Paul Adsett]

Was it Heurtier that put a couple of rubies in the CENTER of the gate plate to keep the film flat? How did that work out?

[Dominique De Bast]

Was it Heurtier that put a couple of rubies in the CENTER of the gate plate to keep the film flat? How did that work out?

I don't know if that document exists in English.


https://collection.click-clack.fr/he...rs-5eme-serie/

[Douglas Meltzer]

Thanks, Dominique. Here's a translation:

[Dominique De Bast]

Brillant, Doug!

[Paul Adsett]

Very interesting, but the risk of scratching the center area of the film would be too much for me!

[Steve Lee]

I think that ruby design gate runner was just asking for trouble. Every time I see a Heurtier projector for sale in france it makes me laugh. As they are always advertised as a Knocker projector!
I don't know if this is referring to the sound it makes when running, or something else?

It doesn't bear thinking about.

[Rob Young]

Truly the work of mad genius! All these years in this hobby and never seen that before, thanks Dominique and Doug.

I’m with Paul though; I’m paranoid enough about scratching film. I still think it’s brilliant though, even though it’s definitely asking for trouble!

[Oliver Feld]

Yes, thank You, Dominique and Doug

[Dominique De Bast]

Every time I see a Heurtier projector for sale in france it makes me laugh. As they are always advertised as a Knocker projector!
I don't know if this is referring to the sound it makes when running, or something else?

Just a bad translation of Heurtier 😉

[Steve Lee]

I didn't think I would have to explain this one , but a knocker or a pair of knockers is English slang for a pair of breasts.

[Dominique De Bast]

I didn't think I would have to explain this one , but a knocker or a pair of knockers is English slang for a pair of breasts.

🤣🤣🤣 Thanks.

[Matthieu van der Sluis]

I was thinking of attaching a larger reel on the focusknob so I can focus more precise

[Dave Bickford]

The general consensus seems to be that the common rotating snail cam engaging a pin on the side of the lens barrel is probably the worst possible design.

I have a Eumig with this design, and the focusing is utterly useless. There is a small clip holding a couple parts in place that keeps popping out. In order to focus, I have to use a combination of turning the focusing knob while also manhandling the lens into place. Needless to say, this projector is now gathering dust.