Film-Tech Forum ARCHIVE: Simplex 35 Focusing Knob Question

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Posted by Michael Voiland (Member # 5386) on 12-22-2009, 05:27 AM:

We have 5 simplexes all different in how they have been mantained over the years. One of them has a focusing knob that is almost impossible to turn. Its come to the point where It takes a good 30 to 45 seconds to turn the knob one or to turns to get the lens to focus after a lens change. I have been switched lenses during the credits of other movies so the next movie will be focused and people don't see me fighting with the focus. Does anyone know how to loosen up / oil the focusing knob shaft on a simplex?

Posted by Mark Gulbrandsen (Member # 72) on 12-22-2009, 08:29 AM:

The grease in there has turned to goo. It'll have to be disassembled, cleaned, re-lubed and re-assembled. Follow the manual on this one. Procedure is a bit lengthy and you need to get it back together correctly for it to work properly.

Mark

Posted by Tony Bandiera Jr (Member # 2365) on 12-22-2009, 02:32 PM:

Michael, your real problem is that your lenses are not set up correctly. If you set up your lenses as per my following instructions, you should rarely have to touch that focus knob. It is a simple thing to do but it does take some time.

Step 1: Prepare a loop of film, like sharp credits or if you can get some, SMPTE RP-40 test film;
Step 2, Thread and run the loop, lamp on and dowser open;
Step 3, Set the focus knob to it's midpoint (turn it fully one way and then back the other till it stops, counting the number of turns, on most Simplexes it's about three full turns, so set it at 1 and one half turns from either stop);
Step 4, DO NOT TOUCH THE FOCUS KNOB AGAIN DURING THIS PROCESS!!;
Step 5, starting with the scope lens, loosen the lens setscrews (or clamp screws on older adapters) SLIGHTLY, you want the lens just loose enough to be able to move with some effort but not so loose that it can move freely or fall out);
Step 6, Insert the lens adapter ALL THE WAY into the lens holder, then tighten the LENS HOLDER CLAMP KNOB slightly so the ADAPTER can't move around;
Step 7: Shift THE LENS AND ONLY THE LENS in the adapter until it is sharply focussed and the scope image is straight and not crooked;
Step 8, Loosen the LENS HOLDER CLAMP KNOB and carefully push the adapter and lens out enough to tighten the LENS SETSCREWS. DON'T LET THE LENS MOVE while you do this.
Step 9, Reseat the lens adaptor and lens into the holder to see if you're still in focus. If not, repeat steps 5 - 8 and check it again. If focus is still good, move on to your flat lens repeating the above.

Reading the above makes it sound hard, but it really isn't and should not take more than 15 mins. to 1/2 hour to set up both lenses, even faster after you've done it a few times.
Properly set up, you should NEVER have to make big changes in focus when switching lenses, it should be only very minor tweaks if at all.
Be sure to MARK EACH lens to it's own projector.
You will be a lot happier and so will your audiences.

Posted by Gordon McLeod (Member # 33) on 12-22-2009, 02:35 PM:

no mater how carefully you set focus rings one usually needs to make a 1/4 turn of the focus knob to get proper focus

Posted by Demetris Thoupis (Member # 833) on 12-22-2009, 02:38 PM:

Tonys' procedure is the correct one. Do the Simplexes have only one common focus knob like the Kinotons? The only problem would be if you have local subtitled titles which are almost never in focus with the emulsion side of the film so you inevitably have a slight blur on the subtitles unless you do a certain trick to shift the lens holder only a few mm on one side to achieve proper focus. Good luck and also don't forget WD40 [Smile]

Demetris

Posted by Tony Bandiera Jr (Member # 2365) on 12-22-2009, 02:40 PM:

Gordon I disagree, in all the screening rooms I've set up one rarely has to do more than 1/8 turn or less to stay in focus. In many cases with the new mylar stock NO CHANGE AT ALL is not uncommon. Bear in mind I'm also working with some short focal length lenses too which are super fussy on focus. (45-55mm mostly)

If it still takes a full 1/4 turn with a lens change there are other issues at play, like slop in the lens holder assembly.

Demetris, yes, only one knob if the Simplex has the single lens holders (which is what Michael appears to have) and IIRC the Simplex Turrets have knobs for each lens.

Posted by Demetris Thoupis (Member # 833) on 12-22-2009, 02:48 PM:

Hmm. Never seen a single lens holder with multiple knobs [Roll Eyes]

.

Sorry Tony [Smile]

He he. The Kinotons' lens turrets have one common focus knob whic shifts the whole turret back and foth and not each individual lens that is why I was asking if the Simplexes use the same system as I have not seen one.
Demetris

Posted by Tim Reed (Member # 137) on 12-22-2009, 03:40 PM:

Yes, the lens holders are independent in a turret like the TU-2000.

Posted by Michael Voiland (Member # 5386) on 12-22-2009, 04:57 PM:

I was looking through the simplex projector manuals and could not find the part where they talk about the focusing knob. Maybe I am looking in the wrong part of the manual.

Posted by Tony Bandiera Jr (Member # 2365) on 12-22-2009, 11:18 PM:

quote:
Hmm. Never seen a single lens holder with multiple knobs [Roll Eyes] .

Sorry Tony [Smile] He he. The Kinotons' lens turrets have one common focus knob whic shifts the whole turret back and foth and not each individual lens that is why I was asking if the Simplexes use the same system as I have not seen one.
Demetris

LOL I once thought I had seen a single-lens Century with multiple focus knobs. [Big Grin]

Now that you mention it, you're right about the Kinotons..mine at UC Irvine have those blasted turrets and the single knob..After I set the lenses they stay in focus pretty well, but the damn turret and aperture changer never seem to index to the same place twice..I absolutely hate them.

Anyone out there got a pair of single-lens mounts and holders for an FP-20 they'd like to get rid of? [Big Grin]

quote: Michael Voiland
I was looking through the simplex projector manuals and could not find the part where they talk about the focusing knob. Maybe I am looking in the wrong part of the manual.

Michael, look in page 25 of the Simplex parts manual here on the site, (Page 25 of the pdf file, it is page 1-18 of the actual manual.)

Posted by Ian Parfrey (Member # 5122) on 12-23-2009, 12:05 AM:

Tony

Is the FP20 turret similar to the DP75?

If they are, you have my sympathies.

Posted by Steve Guttag (Member # 268) on 12-23-2009, 03:42 AM:

I know we have pulled Kinoton turrets and installed single-lens holders! I'm not a huge fan of turrets in general and found the Kinotons to mainly get "in-the-way".

Steve

Posted by Ian Parfrey (Member # 5122) on 12-23-2009, 03:55 AM:

Steve.

If they're anything like these I'm not surprised!

Posted by Steve Guttag (Member # 268) on 12-23-2009, 08:58 AM:

And with an X60 lamphouse no less (I'm guessing).

The DP75 turrets were somewhat unique in that they angled the other lens out of the way. The ones I've pulled just had two or three straight openings.

Steve

Posted by Tony Bandiera Jr (Member # 2365) on 12-23-2009, 05:14 PM:

Ian, nope mine are triple-lens and keep the lenses in the same plane, which makes it's lack of focus stability even more puzzling.

Steve, you got a set of single-lens assy's on hand? If not let me know as soon as you find a pair..

Posted by Steve Guttag (Member # 268) on 12-23-2009, 05:31 PM:

The holders themselves we tend to have plenty of (70.6mm, particularly if you don't mind them starting life as 16mm holders)..the focus racks themselves, not so much but they are available new and are only held on by three screws. Make sure you have the alignment fixture to get them aligned right and fast...you can do it without it but it takes much longer to measure/move/measure/move...etc.

Steve

Posted by Michael Voiland (Member # 5386) on 12-29-2009, 03:57 PM:

Out booth tech was out we ended up getting it pulled apart. The grease was gunked together. Its not got some oil in there after we scraped away all the grease. Thanks for the help.