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Author Topic: Focusing Frustration
Paul Adsett
Film God

Posts: 5003
From: USA
Registered: Jun 2003

- posted November 25, 2009 12:58 PM      Profile for Paul Adsett     Send New Private Message       Edit/Delete Post 
What is it about Elmo projectors that keeps you fiddling with the focusing knob during the film? Both my GS1200'S seem to have 'rubbery' focusing, you can never seem to get that razor sharp condition across all areas of the screen at the same time, and if you do, it does not seem to stay that way for very long. So showing films on a GS, at least for me, means riding the focusing knob during the reel.
Contrast that with my Eumig's which seem to really 'snap' into sharp focus and then stay that way throughout the reel.

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The best of all worlds- 8mm, super 8mm, 9.5mm, and HD Digital Projection,
Elmo GS1200 f1.0 2-blade
Eumig S938 Stereo f1.0 Ektar
Panasonic PT-AE4000U digital pj

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Michael O'Regan
Film God

Posts: 3085
From: Essex, UK
Registered: Oct 2007

- posted November 25, 2009 02:07 PM      Profile for Michael O'Regan   Email Michael O'Regan   Send New Private Message       Edit/Delete Post 
Is this problem common to all Elmos or just the GS?

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Douglas Meltzer
Moderator

Posts: 4554
From: New York, NY, USA
Registered: Jun 2003

- posted November 25, 2009 05:12 PM      Profile for Douglas Meltzer   Email Douglas Meltzer   Send New Private Message       Edit/Delete Post 
Paul,

Sorry, but I don't have that problem on either my standard GS or the xenon model. Strangely enough, I had a Eumig which suffered from that!

Doug

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I think there's room for just one more film.....

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Tony Milman
Phenomenal Film Handler

Posts: 1336
From: United Kingdom
Registered: Jun 2003

- posted November 25, 2009 05:23 PM      Profile for Tony Milman   Author's Homepage   Email Tony Milman   Send New Private Message       Edit/Delete Post 
Neither do I but maybe that's my eye sight

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Tony

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Graham Sinden
Phenomenal Film Handler

Posts: 1131
From: Kent, UK
Registered: Aug 2005

- posted November 25, 2009 05:34 PM      Profile for Graham Sinden   Email Graham Sinden   Send New Private Message       Edit/Delete Post 
Paul, I know how you feel but I always put that down to using the Elmo 1.0 lens which is affected by the heat. Try a 1.3 and it might be better.

Just what has happened to your photo??

Graham S

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Joe Taffis
Phenomenal Film Handler

Posts: 1592
From: United States
Registered: Jun 2003

- posted November 25, 2009 05:46 PM      Profile for Joe Taffis   Email Joe Taffis   Send New Private Message       Edit/Delete Post 
Graham S....what's that about the heat affecting the Elmo 1.0 lense?

[ November 27, 2009, 03:14 PM: Message edited by: Joe Taffis ]

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Joe Taffis

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Graham Ritchie
Film God

Posts: 4001
From: New Zealand
Registered: Feb 2006

- posted November 25, 2009 07:26 PM      Profile for Graham Ritchie   Email Graham Ritchie   Send New Private Message       Edit/Delete Post 
Paul
Is it possible it could be down to a bit of film shrinkage on some prints. I do have films that are perfect where you can focus and leave others not so.

Also I think one of the problems with Super8 is that it has a short depth of focus with its small frame area compared with 16mm so any slight change of shape on the film going through the gate can look quite bad, myself I usually sit next to the projector for those focus adjustments where as with much of my 16mm I dont.

Graham.

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David Kilderry
Jedi Master Film Handler

Posts: 963
From: Melbourne, Victoria, Australia
Registered: Feb 2006

- posted November 25, 2009 08:28 PM      Profile for David Kilderry   Author's Homepage     Send New Private Message       Edit/Delete Post 
It is a well known Elmo weakness that I am sure has been discussed here before.

Every one of my Elmo 1200 series projectors has suffered from it. The focusing system is less than precise especially compared to the Eumig 900 series.

Sankyo projectors suffer from it as well; simply too much slop and with wear, free play in their focus adjustment design.

This is one area where the Eumig beats the Elmo hands down.

David

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Paul Adsett
Film God

Posts: 5003
From: USA
Registered: Jun 2003

- posted November 26, 2009 09:36 AM      Profile for Paul Adsett     Send New Private Message       Edit/Delete Post 
I think you are right David. The lens is just not held very tightly or very precisely on the Elmo's - when you focus you can actually see the lens rock a little from side to side. Also, there is insufficient spring force to bias the lens against the snail cam, so you end up with a huge amount of 'backlash' when you rotate the lens knob.
On the Eumigs, the lens is heavily sprung into a 'v-block' which is precision machined directly into the chassis and exactly perpendicular to the plane of the gate, and there is a really strong spring to push the lens against the snail cam - so there is no lens wobble at all.
Does anybody have a procedure for setting up the lens on the GS1200? I know that you adjust the little screw by the gate for side-to-side focus, and loosen the two lens mount screws to adjust top-to-bottom focus, but this is a real hit and miss adjustment because there is so much 'cross-talk' between them How exactly are you supposed to do this?

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The best of all worlds- 8mm, super 8mm, 9.5mm, and HD Digital Projection,
Elmo GS1200 f1.0 2-blade
Eumig S938 Stereo f1.0 Ektar
Panasonic PT-AE4000U digital pj

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Brad Miller
Administrator

Posts: 525
From: Dallas, TX, USA
Registered: Jun 2003

- posted November 26, 2009 12:00 PM      Profile for Brad Miller   Author's Homepage   Email Brad Miller       Edit/Delete Post 
Short of getting some actual SMPTE target film, you can get some K40 and make your own. Just get a large pattern of thin vertical and horizontal lines drawn as big as you can get (as in, wall-sized if possible) and film it. When you get it back from the lab, you will have something you can use as a reference to obtain ideal lens adjustment on. Just make absolute sure when you filmed it that the camera was perfectly centered both horizontally and vertically to the "wall target".

If someone on the forum was enterprising, I'll bet quite a few people here would want a 50 foot roll of this.

Adding forced air cooling to the gate also works wonders for keeping the film from buckling if you have too much heat from a large lamp, although if you are using a stock Elmo 250W lamp I doubt you need it. I would look at the barrel alignment more than anything.

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Joe Taffis
Phenomenal Film Handler

Posts: 1592
From: United States
Registered: Jun 2003

- posted November 26, 2009 03:36 PM      Profile for Joe Taffis   Email Joe Taffis   Send New Private Message       Edit/Delete Post 
I use a SMPTE test film. Steve Osborne at THE REEL IMAGE sells them for around $25.00.

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Joe Taffis

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John Hourigan
Master Film Handler

Posts: 301
From: Colorado U.S.A.
Registered: Sep 2003

- posted November 26, 2009 11:33 PM      Profile for John Hourigan   Email John Hourigan       Edit/Delete Post 
Paul, I agree with you -- focusing seemed to be more precise (and more "stable") on my Eumig versus my Elmos. I find that I have to "ride" the focus knob on my Elmos, which does take some fun out of running film shows.

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Brad Kimball
Phenomenal Film Handler

Posts: 1171
From: Highland Mills, NY USA
Registered: Jun 2003

- posted November 27, 2009 03:56 PM      Profile for Brad Kimball   Email Brad Kimball   Send New Private Message       Edit/Delete Post 
I have some B&H 2500 series untis (16mm) that all suffer from the same problem. I have to tape the focus knobs on all of them in order to not have to hold the knob still throughout a movie.

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Graham Sinden
Phenomenal Film Handler

Posts: 1131
From: Kent, UK
Registered: Aug 2005

- posted November 27, 2009 04:55 PM      Profile for Graham Sinden   Email Graham Sinden   Send New Private Message       Edit/Delete Post 
Joe, Im not sure what I said was correct but I was always told that the elmo 1.0 lens is much harder to focus (and keep in focus) than the standard 1.3 due to the way its built and the sensitivity. However its a long time since I used the old 1.3 lens so its difficult to compare the two.

Dont know if its the same as SMPTE film but Derann sold their 'Scope alignment Reel' on a 50ft reel

Graham S

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Thomas Murin, Jr.
Master Film Handler

Posts: 260
From: Lanoka Harbor, NJ, USA
Registered: Sep 2009

- posted November 27, 2009 04:56 PM      Profile for Thomas Murin, Jr.   Author's Homepage   Email Thomas Murin, Jr.   Send New Private Message       Edit/Delete Post 
My B&H DCM suffers from this. Yet, I had the lens out yesterday before a screening to give everything a good cleaning and when I was running the show, I only had to adjust the focus at the beginning of each reel.

Not sure what I did but I hope it lasts!

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My crummy Deviant Art account. Read my poetic tribute to the internet comic strip Ozy & Millie and view my crappy attempts at art.

http://cougartiger.deviantart.com/

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