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Beaulieu 4008 viewfinder adjustment


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#1 Rafael Rivera

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Posted 25 January 2011 - 09:11 PM

Sometime ago I found Martin Baumgarten's instructions on how to adjust the 4008ZMII Viewfinder X/Y position to match what the lens sees, and eventually I followed his instructions and took pictures of the process which I have finally posted here:


4008 Viewfinder Adjustment
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#2 Jean-Louis Seguin

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Posted 26 January 2011 - 09:09 AM

Great work. Excellently described!

Cheers,
Jean-Louis
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#3 Jorge Rondao

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Posted 27 January 2011 - 06:07 PM

Hi, Where you place this target to pitch, in front of the gate without a lens?
Great work.
Regards
Jorge
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#4 Rafael Rivera

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Posted 28 January 2011 - 07:01 PM

Great work. Excellently described!

Cheers,
Jean-Louis



Many thanks Jean-Louis!
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#5 Rafael Rivera

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Posted 28 January 2011 - 07:15 PM

Hi, Where you place this target to pitch, in front of the gate without a lens?
Great work.
Regards
Jorge


Hola Jorge, the target is placed on a filter and threaded to the front of the lens. Then attach the lens to the camera before doing the adjustment.

I've added one more picture showing the target and how I mounted it to a filter.

Edited by Rafael Rivera, 28 January 2011 - 07:16 PM.

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#6 Andries Molenaar

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Posted 29 January 2011 - 03:29 AM

This object infront of the lens is not working and you are adjusting to a random obejct.
The centre of the lens is not necessarily in the centre of the frame of the camera.

The essence is to align the viewfinder with the frame of the camera's filmgate. I.e. the area the camera is registering on the film and what you want the viewfinder to be aimed on.

The target should be on a wall, the camera on a steady mount.
Open the shutter and project the camera's gate onto the wall using a light in the chamber and through the lens mounted on the camera.

Align the target frame inside of the projected frame.

Then align (rotate) the eyepiece of the camera to the horizontal /vertical lines of the target.
Then use the two adjusters to center the viewfinder on the target if needed.

The rotational adjustment is far more frequently needed as the eyepiece sticks out
and many owners treat it a like something mounted to their car rather then to
a precision instrument.

This is in brief how it is described in a manufacturer's repair manual
and to my memory as I read it in (Baumgarten's) instructions.

Edited by Andries Molenaar, 29 January 2011 - 03:33 AM.

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#7 Andries Molenaar

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Posted 29 January 2011 - 04:14 AM

.
.
.
This is in brief how it is described in a manufacturer's repair manual
and to my memory as I read it in (Baumgarten's) instructions.


And indeed:

---> If you want an exact confirmation of centering, place the camera on a sturdy tripod...then place a perfectly perpendicular (and in a parallel plane) piece of white card stock or paper rigidly held in position. Focus the lens in the viewfinder onto this cardstock. Then place a small front surface mirror into the film chamber and at a 45° degree angle to the filmgate. Have the camera setup on a sturdy tripod. Open the camera's shutter manually, by turning the Erlson/Pilotone shaft with a small screwdriver counterclockwise until the shutter is open. [NOTE: If you have an earlier 4008ZM or 4008S model...you can still turn this shaft, even though the Erlson threaded unit does not exist on these models. Now....with the shutter fully open.....project a strong beam of light using a small Maglite or similar onto the mirror which will then project an illuminated blank frame image onto a white cardstock set before the camera at about 12 to 18inches. Mark the outer corners of the projected gate onto the cardstock with a small marker or tape. Close the shutter, so that you can view thru the viewfinder...and critically examine that the viewfinder coincides with these marks you made. If not...the readjust the viewfinder X/Y adjusters until the marks create a perfectly centered image in the viewfinder. NOTE: Use either tape or a fat marker so that the markers you make can easily be seen in the viewfinder for ease of adjustment.


Edited by Andries Molenaar, 29 January 2011 - 04:15 AM.

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#8 Jorge Rondao

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Posted 29 January 2011 - 06:44 PM

Hi, Thanks for the excellent describe.
Regards
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#9 Rafael Rivera

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Posted 29 January 2011 - 10:09 PM

Very cool, thanks for the clarification on how to do it!
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#10 Jorge Rondao

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Posted 11 February 2011 - 06:13 AM

Now I am having trouble tuning and focusing diopter of the viewfinder, my eyes are not as new, and am already with 1.75 diopters, the problem is that, when setting the focus and the viewfinder diopter with Ground Glass I see all well focused, but when remove the Ground Glass it all slightly blurry, my doubt is what will make the proper focus, tune to my eyes with or without the Ground Glass? what will it be the real focus?
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#11 Andries Molenaar

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Posted 11 February 2011 - 12:36 PM

Now I am having trouble tuning and focusing diopter of the viewfinder, my eyes are not as new, and am already with 1.75 diopters, the problem is that, when setting the focus and the viewfinder diopter with Ground Glass I see all well focused, but when remove the Ground Glass it all slightly blurry, my doubt is what will make the proper focus, tune to my eyes with or without the Ground Glass? what will it be the real focus?


The image without groundglass is a virtual aerial image. It is only for framing and aiming. Use the GG for focusing, otherwise use the distance markings on the lens. I don't understand how your aerial image can not be sharp when the GG is in focus.

S8 has so much depth-of-field that it hardly makes a difference when your are 10cm off at past 1 meter.

Good luck.
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#12 Jorge Rondao

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Posted 11 February 2011 - 01:15 PM

Hi, Also I do not understand how it is not in focus, but actually to be in focus I have to make new adjust in the ring of the viewfinder.
I did the texte with a focus card to 3mt from de lens and focus on the lens to 3mt.
will be likely that some element inside the viewfinder moved from side, or will be by my eyes diopters that makes that difference?
Anyway I always must set by Ground Glass.
Thanks
Regards
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#13 Martin Baumgarten

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Posted 11 February 2011 - 03:45 PM

Jorge, the ground glass image is what shows the actual focus sharpness. Make sure when setting ground glass clarity, you either remove the lens from the camera, or shift it into a way off macro position so that the lens image is nothing but white light.....keep the aperture fully open as well. Now, adjust the viewfinder dioptre so that the ground glass is clear and you can see its texture. IF you try doing this while an image is showing, it will throw off the adjustment since visually you'll be distracted by an image. All you want to see is the ground glass grain texture only. Once this is set, focus the lens sharply on an object, preferably newsprint taped to the wall and then compare the distance setting on the lens scale to that of a good measuring tape. As long as the lens is in good condition and not damaged or off-focus, the measurement at 5ft, 10ft, and 15ft settings should match up between the lens scale and the measuring tape.

The aerial image usually is always clear and in focus when you remove the ground glass screen away. If it is not, then there could be some other problem. The Ground Glass screen setting might need some adjustment, since it is on a movable platform to flip in and out of the viewfinder path. If you already have the camera open to set the X/Y alignment, you should be able to see the Ground Glass Frame as it moves in and out of position, and check to see that it is fully in the in position. If the moving device has come out of adjustment, this will have to corrected of course.

Anyhow, to double check this, you'll have to check the actual focus in the film gate. This is not easy to do without a filmgate prism of some kind. However, you can make do with another method. Cut a small piece of Sctoch Tape. The tape is translucent similar to ground glass, and is very thin, enough for this experiment setup. Make the X mark on the tape's STICKY Side. It will have to be the size of the Super 8 Frame of course, and then carefully place the tape on the Film Gate so it is flat and accurately lined up. Another method is to use a piece of clear or light gray Super 8 scrap film.....however, this is very difficult to keep accurately in place in the camera's gate.

Place the camera on a sturdy tripod, set it from a wall which has an 8 x 10 inch piece of white paper taped to the wall, set the camera's distance at 5 feet (the minimum focusing distance for either the 6mm-66mm Schneider, 8mm-64mm Angenieux lens etc), Now using a small strong light, such as a MagLite or small bright multi LED light (flashlight, handtorch etc), shine this through the Film Gate with the Shutter in the OPEN position. To get a proper beam of light, you will need a small mirror at a 45 Degree Angle, otherwise there will be too much light loss. Adjust the zoom lens somewhere to 40mm to 60mm, so that the illuminated field on the paper is easily visible. The X pattern should be sharply in focus on the white paper. You will y have to dim the room lights to be able to study the image. Allow your eyes to get used to the darkened room, before doing this test. This will take at least 10 to 15 minutes for them to get used to the dark enough. Otherwise, even with a small bright light, the image will still seem a bit dark and it will be frustrating to determine image sharpness. To get a brighter image, you will have to set the camera closer to the paper, but would first have to reset the lens macro focus setting in the viewfinder until it is sharp. I recommend taping the Macro Lever so it doesn't move on you. I recommend taping the camera lid so it doesn't close on you. You can also set the camera on it's side on the Tripod, so that the film chamber is more readily accessable and it makes your work easier. Use a good grade electrical tape that doesn't leave residue behind.

I do recommend having someone help you, as an extra pair of hands also with a small flashlight so you can see what you're doing without losing your night-vision will be very useful.

Also, while more difficult, it is possible to use an old scrap Super 8 cartridge as the basis for building a FilmGate Focus Checker. Gut the cartridge so you can build your unit. With a small front surface mirror at a 45 degree angle, an accurately positioned piece of etched glass, marked plastic etc to represent the Film's Emulsion Position at the gate of the cartridge....all cut so to fit into the camera gate when the Dummy Cartridge is inserted......and then a strong Film Lupe such as an 8x power minimum but ideally a 20x or so, will help you see the focused image. With such a Gate Checker, you won't need to fiddle in darkness, but can examine the film plane focus and compare it to the viewfinder. This type of a gizmo will work with any side loading Super 8 camera. IF using a rear loading Super 8 camera, it's a bit easier to build as no mirror is needed. You would only have to have a small focusing telescope type design built thru the rear of the cartridge wall and lined up with the small ground glass or plastic focusing screen. KODAK used to offer something similar many years ago for their Double 8mm Magazine cameras and their 16mm 50ft Magazine cameras.

Focusing disparity on Super 8 cameras from what is seen in the viewfinder to what is captured on film, has always been one of the problems of many Super 8 cameras and filmmakers. It either requires several actual film tests and processing of course to check and double check, all requiring extra time and cost. Also, if a fixed lens (or removable lens even) can be checked and either remarked as to how to set it by scale to know for sure the focus setting, it will be immensely helpful. The only other option is costly lens collimation, and this of course just isn't worth bothering with on lower cost cameras. Lastly, despite the cost of film & processing........one can use a single cartridge of film to check many cameras, or even just to check one, by only using a few feet, and then using the film in a known working camera for movies. Then only a small section of film has been used for the test in another camera or cameras. Do slate the test sequences so you know which camera it belongs to!

I hope this helps. Otherwise....welcome to the age range of those of us who have eye focusing problems as we get older!

Best regards,
Martin Baumgarten
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#14 Jorge Rondao

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Posted 11 February 2011 - 06:17 PM

Hi,Thank you for the excellent explanation, this time resulted only taking the lens and making the focus on the GG, yesterday did not work very well also because of after the 14h of work in studio and have my eyes so tired that already blurred for they belonged.:)
Best regards
Jorge
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