On interchangeable lens cameras, often a given lens will not have the exact same collimation as the original lens that was fine-tuned at the factory. Collimation is the adjustment of a given lens to a camera body, so when on that particular camera body the lens will provide correct focus to infinity as well as to the lens scale settings (in theory providing the lens scale settings are accurate). Professional cinematographers often use a Field Lens Collimator, such as the Richter Field Collimator, to allow them to make fine-tuning adjustments out in the field, since often in the course of lens interchanges done many times and between various camera bodies...they have to be absolutely sure the focus is correct. Much of professional filmmaking uses measuring tapes from the subject to the film plane to set the focus then via the lens scale.

Beaulieu Super 8mm cameras, have their lenses factory calibrated (collimated) to that particular camera body, just as is done on their's and other's 16mm and 35mm counterparts.When using a Single-Lens-Reflex camera, you will always be able to bring the lens into sharp focus......it's just that the lens scale, and/or the infinity setting will be off. This problem is more exagerated on screw mount based camera lenses and bodies, due to minute thread wear.

A low cost way to collimate a given lens would be to use a gate prism and a test target. Set it up to say 10ft and various other distant increments, and adjust the lens until it's in focus for the 10ft etc settings as measured from the subject plane to the film plane using an accurate measuring tape or device. A more accurate way is using a collimator, preferably a bench collimator with a good light source, however this is out-of-the question for the home Super 8 filmmaking enthusiast. And I don't know of any sources for a gate prism for Super 8mm cameras. So...this brings me to another way to do this. If your Beaulieu Super 8mm camera is accurate otherwise in its viewing system (correct focus alignment between the lens flange to film plane as compared to the lens flange to focusing screen), then you can setup your own lens using a test target (this can be newsprint taped to a wall).

Set up the camera at 10ft from the test target and make sure that the camera is as accurately perpendicular to the test target plane as possible. Make sure the viewfinder dioptre is correctly set for your vision. Adjust the zoom to the maximum setting and make sure the aperture is fully open. Set the lens to the 10ft mark and observe the degree of sharpness or lack of sharpness of the test target. Then bring the lens in to sharp focus, if it is out of focus. Note the distance setting on the focusing barrel of the lens, and write down this deviation. Now conduct this same test for 15ft, 25ft and infinity. 25ft and infinity settings do not have to be perfectly perpendicular as you'd never be able to ensure this..and it's not critical in this initial test setup. If the lens focuses sharply at the infinity setting, move the focusing barrel until it just begins to go out of focus...the threshold as it were. As in the 10ft setup....write down all deviations at the four settings. If you want to go one step further.....do the test for the minimum focusing setting also which is probably about 5ft.

Now, one you have the deviations written down, and are sure that the given lens is out of collimation, you are ready to begin the lens adjustment phase. At the rear of each Beaulieu Super 8mm zoom lens (including the very early 2008S Angenieux and Schneider lenses) an adjustment slot on the rear optic. You will need a proper lens spanner for this, as you certainly don't want to go scratching the rear element! Anyhow....you will need to turn this rear adjustment in a 5 minute increment (if 360º degrees equal a full rotation...then 5 minutes on a clock face equals the amount of minimum rotation adjustment we will want to make initially). Using a clock face concept makes it easier to visual the amount of rotation adjustment of the rear element. By turning it clockwise the element is screwed into the lens and thus shifts the focus closer. By turning it counter-clockwise the element is screwed out of the lens and thus shifts the focus further out.

Although just a rough guide....use these parameters:

1. 15ft setting as per test reads 20ft on the deviation.......adjust lens clockwise.
2. 15ft setting as per test reads 12ft on the deviation....adjust lens counterclockwise.

Now, please NOTE: This alternative method of adjusting the lens focusing barrel will not work for infinity if the lens cannot focus to infinity as it stands. That has to be done via the rear element module adjustment. However.....a given lens will produce sharp results at the lens scale settings up to the distance setting where the focus approaches nearer to infinity and begins to fall off. IF you need to use the scale for focusing, then this is a poor man's quick fix until you can have the lens properly collimated.

Another method of setting the lens up without doing anything to actually adjusting the lens...but then being able to correctly set it via the scale is this. Tape some white or light colored gaffers tape in small pieces to the main focus settings on the lens. With a fine point permanent felt tip marker or pen....write down the actual focus settings. This will allow you to use these tape marks temporarily until you can get the lens in question properly collimated.

The actual adjustment of a lens' collimation is best left to a camera repair technician, but if you are adept at using repair tools, and can work carefully to avoid damaging the lens element(s), then try it yourself. I leave you with one last resort to a quick temporary fix. This works best if a given lens focuses beyond infinity....in other words the lens comes into focus at infinity prior to reaching the infinity mark. Just unscrew the lens from the camera body a bit until there's a gap. Place a couple pieces of thin paper cut out to fit around the base of the lens and slide these under and then tighten the lens again. Continue to build up the spacing with these paper 'shims' until the lens comes into correct focus at infinity at the infinity setting. Double check the lens settings for 5ft, 10ft, 15ft, and 25ft also via the test target, and add or subtrack these paper shims as is necessary. This procedure can be done quickly as can the lens barrel adjustment. The paper shims are only good for this setup while this lens is on this given camera body...and of course...only IF the lens comes into Infinity focus early. The same procedures are compatible with 16mm motion picture cameras and are offered only as a temp fix until you can get the lens properly collimated for the camera body.

Finally...once a lens is collimated to a camera body...it is set up ONLY for that camera, and will NOT necessarily focus correctly on another similar Beaulieu Super 8mm camera body. In a perfect world, lenses would align properly and also be in correct focus. However...with the very tiny distance and great magnification of Super 8mm camera lenses relative to the film frame....any slight wear to the body or lens flange threads will alter the focus ever so slightly, and begin to throw it off more as time goes on with each lens removal and replacement. The professional recommendation is to have lenses collimated to the camera body frequently IF the lens is going to be interchanged often. In practice with the few amounts a zoom lens is removed from a Super 8mm Beaulieu camera body....it will hold its collimation for a long time. One other important item....this entire information above mainly pertains to the screwmount lenses. The later breech-lock 6008 and upward Beaulieu cameras will hold their collimation to their originally setup zoom lenses over many many removals. This is because of the different lens mount design. However....even on these cameras, there is a useable C-mount and the foregoing applies to using any screwmount lenses on these later model Beaulieus also.

Happy Filmmaking!
Best wishes, Martin W. Baumgarten

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