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Author Topic: Adjusting Focus
Ian Bailey
Master Film Handler

Posts: 317
From: Nambucca Heads, Australia
Registered: Jun 2003


 - posted 01-14-2005 06:18 AM      Profile for Ian Bailey   Email Ian Bailey   Send New Private Message       Edit/Delete Post 
I find adjusting focus the hardest thing in operating a 35mm projector.The problem I have is knowing the best spot in the projected image to look at when trying to adjust focus.I realise now that this problem would not be as difficult if i had top quality lenses but at the moment I have to be content with what I have got.Any suggestions here would be very helpful.

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Brad Miller
Administrator

Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99


 - posted 01-14-2005 06:30 AM      Profile for Brad Miller   Author's Homepage   Email Brad Miller       Edit/Delete Post 
*Get a pair of binoculars and use them to focus on the grain. (Be sure and focus the binoculars on the performations of the screen in a bright area first though.)

*Try and hit optimum focus off-center right. That will put you not at the edges of the frame, nor at the center. Generally that's a good target to achieve uniform focus on most setups.

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Jeremy Fuentes
Mmmm, Dr. Pepper!

Posts: 1168
From: Corpus Christi, TX United States
Registered: Jan 2004


 - posted 01-14-2005 06:51 AM      Profile for Jeremy Fuentes   Email Jeremy Fuentes   Send New Private Message       Edit/Delete Post 
Or you could just focus it the best you can, ask 5 people if they think its focused, and if 3 out of 5 think its focused, then that should be good enough. [thumbsup]

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Thomas King
Expert Film Handler

Posts: 119
From: Sheffield, Yorkshire, England
Registered: Oct 2004


 - posted 01-14-2005 07:34 AM      Profile for Thomas King   Author's Homepage   Email Thomas King   Send New Private Message       Edit/Delete Post 
In my experience, one man's focus is another man's blurry mess. I suppose that's where having a non-flat focus comes in handy; you can tell one guy to look at one side of the screen and another guy to look at the other!

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Bill Enos
Film God

Posts: 2081
From: Richmond, Virginia, USA
Registered: Apr 2000


 - posted 01-14-2005 05:41 PM      Profile for Bill Enos   Email Bill Enos   Send New Private Message       Edit/Delete Post 
A rock thru and back to focus on a bright scene will give excellent results without binoculars. The old guy who trained me in the booth said that if I needed binoculars to focus, somebody else should do it.

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Phil Hill
I love my cootie bug

Posts: 7595
From: Hollywood, CA USA
Registered: Mar 2000


 - posted 01-14-2005 06:20 PM      Profile for Phil Hill   Email Phil Hill       Edit/Delete Post 
Gosh Jeremy, that sure would work! Especially with all the drunks and dopers around... "Yesh, huld it! Pefleck!"/"Kewl dude, duh colurs R sharp, K!"

Brad has the best solution.

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Scott Norwood
Film God

Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99


 - posted 01-14-2005 07:58 PM      Profile for Scott Norwood   Author's Homepage   Email Scott Norwood   Send New Private Message       Edit/Delete Post 
I like to focus on closeups of peoples faces, since there's lots of detail that can be seen if the image is properly focused, and faces are almost invariably photographed in proper focus. With modern film stocks, it's impossible to see grain from the booth without binoculars.

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Peter Mork
Expert Film Handler

Posts: 181
From: Newton, MA, USA
Registered: Jun 2002


 - posted 01-15-2005 04:17 AM      Profile for Peter Mork   Email Peter Mork   Send New Private Message       Edit/Delete Post 
Especially good if Clint Eastwood is in the movie. Failing that, I like tree bark or stone walls.

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Pete Wolla
Film Handler

Posts: 71
From: Tioga, ND, USA
Registered: Jan 2003


 - posted 01-15-2005 09:38 AM      Profile for Pete Wolla   Email Pete Wolla   Send New Private Message       Edit/Delete Post 
i was wondering if the projector is off center (as in running one projector from a change over converted to a platter)will that greatly affect the focus side to side. also what would affect the focus from top to bottom of the screen. i try focus off lettering but it seems to vary by screen position

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Peter Mork
Expert Film Handler

Posts: 181
From: Newton, MA, USA
Registered: Jun 2002


 - posted 01-15-2005 04:50 PM      Profile for Peter Mork   Email Peter Mork   Send New Private Message       Edit/Delete Post 
Projector position doesn't matter that much, as far as focus goes. Where problems arise is in the gate - the "staging area" so to speak, where a tiny variation in the distance from film to lens makes a big difference. There are lots of reasons why you might have problems - anything from crud on the runners to misalignment of the trap - hard to diagnose from here, but removing the trap and cleaning it is a good place to start. Sometimes the solution to problems like this is to add shims (spacers) under the runners to change the angle of the film plane. I've done it, but it takes a lot of trial and error.

Also, maybe you just need better lenses.

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Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99


 - posted 01-15-2005 07:21 PM      Profile for Gordon McLeod   Email Gordon McLeod   Send New Private Message       Edit/Delete Post 
peter said "Projector position doesn't matter that much, as far as focus goes"
sorry that is dead wrong especially with short focal length lens

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Pete Wolla
Film Handler

Posts: 71
From: Tioga, ND, USA
Registered: Jan 2003


 - posted 01-16-2005 07:26 AM      Profile for Pete Wolla   Email Pete Wolla   Send New Private Message       Edit/Delete Post 
thanks for the input i do clean the runners every show (only 3 per week)it may well be the lenses.

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Ferdinando Innocenti
Film Handler

Posts: 79
From: Genova / Italy
Registered: Jun 2004


 - posted 01-16-2005 11:20 AM      Profile for Ferdinando Innocenti   Email Ferdinando Innocenti   Send New Private Message       Edit/Delete Post 
Where I have a remote focusing device, I use a simple RF receiver connected to the turret and a transmitter I hold in my pocket. When I need focusing, I can go just near the screen to have the best focus as possible.

To have the best focus installing the lenses, I think it’s really important lens-shifting, to correct the wrong position of the projector.

Ciao
Nando

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Kevin Markwick
Film Handler

Posts: 43
From: Uckfield East Sussex England
Registered: Sep 2004


 - posted 01-16-2005 05:27 PM      Profile for Kevin Markwick   Author's Homepage   Email Kevin Markwick   Send New Private Message       Edit/Delete Post 
Someone told me years ago that you should always focus on the actors eyes as this is where the audience naturally concentrate
their attention.

It's always worked for me.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999


 - posted 01-16-2005 10:19 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
Sorry, Bill. I think whom ever told you that (if you need binoculars to focus you need someone else) is an idiot. It all depends on the theatre...if you have huge screen a mere 50-feet away...you shouldn't need assistance.

If you have a 20' tall screen 100-feet away...you would need extraordinary eyes to properly focus that.

Binoculars are a tool (or s screen-scope on a Simplex) which can give you a much better result than just the naked eys. With binoculars you can focus down on the grain of the film.

Anyone that has done serious darkroom work has used a focusing apparatus that amounts to having a microscope to focus the enlarger precisely on the paper and that is right in front of you. It is all a matter of how precise you are trying to be.

Steve

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