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» Film-Tech Forum   » Operations   » Film Handlers' Forum   » SIMPLEX X-L: Perfuct Focus? (Page 1)

 
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Author Topic: SIMPLEX X-L: Perfuct Focus?
Jarret Chessell
Master Film Handler

Posts: 288
From: London, Ontario, Canada
Registered: Jan 2009


 - posted 03-28-2009 04:58 PM      Profile for Jarret Chessell   Email Jarret Chessell   Send New Private Message       Edit/Delete Post 
Okay, here's a list of what we have... I'll tell you the problem after [Smile]

Simplex XL (flat gate)
Superlumex 2500W lamp house
Schneider 105mm prime lens with ISCO ultrastar HD anamorphic attachment

The problem is that,
at a glance everything looks great! However on steady pictures you see horizontal smearing (like a sideways travel ghost), white light moving from the outside in. When moving up to the screen to inspect it, it almost looks like a blueish glow.

We used the string method to align the lamphouse, it may not be perfect but it should be fairly close. No matter what you do to the lamp house you cannot completely remove this phenomenon.

The lamp is set to draw 95amps, backing it down does not have any benefit.

Is this the best a flat gate/x-l can achieve, or are we missing something?

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John Walsh
Film God

Posts: 2490
From: Connecticut, USA, Earth, Milky Way
Registered: Oct 1999


 - posted 03-28-2009 05:50 PM      Profile for John Walsh   Email John Walsh   Send New Private Message       Edit/Delete Post 
Maye the lens is not square to the film, causing chromatic aberration?

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Gordon McLeod
Film God

Posts: 9425
From: Toronto Ontario Canada
Registered: Jun 99


 - posted 03-28-2009 06:00 PM      Profile for Gordon McLeod   Email Gordon McLeod   Send New Private Message       Edit/Delete Post 
is it coming from one side only towards the centre
It might be possible that light is getting around the apperture assembly and catching the back element of the lens
with that long of focal length of lens the back element will be some distance from the film plane so there could be stray light getting in

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John Hawkinson
Film God

Posts: 2273
From: Cambridge, MA, USA
Registered: Feb 2002


 - posted 03-28-2009 07:01 PM      Profile for John Hawkinson   Author's Homepage   Email John Hawkinson   Send New Private Message       Edit/Delete Post 
How does it look in flat?

--jhawk

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Dick Prather
Master Film Handler

Posts: 259
From: Portland, OR, USA
Registered: Feb 2002


 - posted 03-28-2009 07:28 PM      Profile for Dick Prather   Email Dick Prather   Send New Private Message       Edit/Delete Post 
Couple of questions:
As John mentions, what does it do in flat?
Do you have the lens shield on the back of the 4" adaptor?
Could you be getting reflections from your port glass?
Dick

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Jarret Chessell
Master Film Handler

Posts: 288
From: London, Ontario, Canada
Registered: Jan 2009


 - posted 03-28-2009 07:38 PM      Profile for Jarret Chessell   Email Jarret Chessell   Send New Private Message       Edit/Delete Post 
we have an isco ultrastar 70mm for flat and it looks great. No sign of chromatic aberration and we made the lens mount perpendicular to the gate.

also, we know it isn't the port glass. The light smear is equal on both sides of the picture....

I'm not sure if I follow what is meant by a lens shield on the 4" adapter?

thanks guys!

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John Hawkinson
Film God

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From: Cambridge, MA, USA
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 - posted 03-28-2009 08:06 PM      Profile for John Hawkinson   Author's Homepage   Email John Hawkinson   Send New Private Message       Edit/Delete Post 
Also, if you remove the anamorphic adapter?

--jhawk

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Jarret Chessell
Master Film Handler

Posts: 288
From: London, Ontario, Canada
Registered: Jan 2009


 - posted 03-28-2009 08:21 PM      Profile for Jarret Chessell   Email Jarret Chessell   Send New Private Message       Edit/Delete Post 
It was doing this with a different anamorphic as well. We just recently switched to the ISCO ultrastar HD anamorphic, more or less hoping to clear up all the issues. We did however at one point change from an isco prime to a schneider.....

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Louis Bornwasser
Film God

Posts: 4410
From: prospect ky usa
Registered: Mar 2005


 - posted 03-28-2009 08:36 PM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
We see this all the time when alignment of the lamphouse is not quite right. Lose the string method, use the scope aperture plate and the scope lens without the anamorphic. Use the method when you tune for equally dark corners, refocus the lamp, and then readjust the entire lamphouse.

BTW: flat gates on XL's are not good enough these days. Curve it to see real improvement! Louis

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Jarret Chessell
Master Film Handler

Posts: 288
From: London, Ontario, Canada
Registered: Jan 2009


 - posted 03-28-2009 09:06 PM      Profile for Jarret Chessell   Email Jarret Chessell   Send New Private Message       Edit/Delete Post 
I don't quite follow how this would work. If I darken all the corners equally how do I know how to move the lamp house? or will it all make sense when I start doing it?

A curved gate is something we've discussed before. Does anyone have a compatible used one they might be willing to part with at a reasonable cost?

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Louis Bornwasser
Film God

Posts: 4410
From: prospect ky usa
Registered: Mar 2005


 - posted 03-29-2009 06:55 AM      Profile for Louis Bornwasser   Author's Homepage   Email Louis Bornwasser   Send New Private Message       Edit/Delete Post 
Alignment occurs when all 4 corners darken at the same rate. Using your normal scope plate (no point in illuminating an area not used) adjust the bulb focus so a corner or two are slightly dark; adjust the lamphouse until 4 corners are equally dark. Refocus bulb. You will probably find a corner or two slightly dark; adjust, repeat, adjust repeat. At some point you will see all 4 corners darken together. Focus the bulb and you are finished.

I would bet against an inexpensive curved gate. They are worth more than the entire flat gate XL.

BTW: it might be possible to reuse the painted part of the gate. That was normal back in the 50's when curved gates were new. Also, with a curved gate, it is imperative that the 2 mounting rods be straight or you will be out of focus from side to side; not so with flat gate machines. (One of the few bad things about the XL.) Louis

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Tony Bandiera Jr
Film God

Posts: 2914
From: Moreland Idaho
Registered: Apr 2004


 - posted 03-29-2009 02:54 PM      Profile for Tony Bandiera Jr   Email Tony Bandiera Jr   Send New Private Message       Edit/Delete Post 
quote: Jarret Chessell
A curved gate is something we've discussed before. Does anyone have a compatible used one they might be willing to part with at a reasonable cost?
Jarret, look at page 3 or 4 of the Equipment for sale forum, I have a curved gate and trap assembly for sale there. It is low mileage from a screening room.

The Super Lumex Lamphouse isn't too bad, but I have found many where the reflector mount isn't aligned squarely to the base of the lamphouse, I have added springs and washers to the reflector mounts to cure that....wish I had pics of one of the worst ones as it's easy to do, just hard to explain over a forum...

The reason it's not square has to do with the casting used to support the reflector. Some are evidently poorly machined at the base.

See if you can find a tech in your area who's familiar with that issue and better yet, has a laser alignment tool for the lamphouse.

As Louis said, forget the string method. It's half-assed and will never get it accurately aligned.

The light shield on the 4" adapter is a sheet metal tube with a flanged base that attaches to the rear of that adapter with three screws. It will help, BUT in some cases where the lens needs to be close to the gate it will not be able to be installed (if the back of the lens sticks out beyond the end of the adapter) or in some cases the setting of the lens won't allow you to open the gate fully either without sliding the whole lens/adapter out a bit.

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Gordon McLeod
Film God

Posts: 9425
From: Toronto Ontario Canada
Registered: Jun 99


 - posted 03-29-2009 03:38 PM      Profile for Gordon McLeod   Email Gordon McLeod   Send New Private Message       Edit/Delete Post 
The issue they are having I doubt is regarding a curved gate as the shorter focal length lens for flat will typically have more issues with gate issues
Try removing the anamorph and see if the problem is still there on the backup by itself ( if it is I would rotate the backup lens 90 degrees and see if the flare rotates if not then I would start looking at spill light getting in
If it does rotate then you have a lens issue

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Jarret Chessell
Master Film Handler

Posts: 288
From: London, Ontario, Canada
Registered: Jan 2009


 - posted 03-30-2009 12:17 PM      Profile for Jarret Chessell   Email Jarret Chessell   Send New Private Message       Edit/Delete Post 
A news update to get everyone's brains going again!

We removed the anamorphic and we still had the blurring. We even tried putting the old prime lens in and saw the same thing. Rotating the lens didn't change anything either.

*cough* Gord, what are the odds of sending that laser...

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Demetris Thoupis
Phenomenal Film Handler

Posts: 1240
From: Aradippou, Larnaca, Cyprus
Registered: Apr 2001


 - posted 03-30-2009 01:44 PM      Profile for Demetris Thoupis   Email Demetris Thoupis   Send New Private Message       Edit/Delete Post 
Well it could be a cracked lens (inside) but since rotating did no difference (rotating the white glare) then its definately not a cracked lens. I've seen the effect you mention with cracked lens at a cinema. Have you noticed if the smearing always happens at the same place or is it happening in random places on the screen? Have you tried using the flat apperture for the scope for testing to see if the smearing still exists? Does it only happens at the very edges of the image?
Demetris

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