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Converting a Bolex H16M to Ultra-16, part 2 August 11, 2017

Last time we tackled the gate widening.  Now for the sprockets.  Because the film touches areas beside the sprocket teeth,  it’s necessary to remove any metal that might cause wear of the image.  Normally this wouldn’t perhaps happen but its better to be safe than sorry.  Removal of the two sprocket wheels is simple with a screwdriver.  Firstly though, ink a mark on the wheel next to a convenient point on the camera. Note there is an angled slot at the edge of each wheel that when lined up will clear the loop-former,  so turn the camera with the backwind key to get it in the right position.  Once removed, carefully grip each sprocket wheel in a vice.  In the photo you can see how much I filed off at each tooth.  It’s brass so quite easy.  Leave some metal at the base of each tooth and don’t damage the tooth itself. Finish off with fine emery wrapped around the needle-file.  Take your time !  Now turn your attention to the other side.  There are two ridges that normally support the film. Important:  don’t  touch the outer one.  The inner ridge needs to be removed.  This can be done with a lathe, or it’s not a long job to simply file it off.  As long as it doesn’t  touch your precious image there’s no problem.  So now you have sprockets that won’t harm the Ultra-16 image in any way.

Replace the sprockets,  ensuring that they are lined up accurately within their guides.  And also line up the ink marks as before.  Don’t tighten the screws properly yet.  Place some film in the threading path through the gate so that the claw engages it,  and close the loop-formers.  If necessary,  turn the sprockets slightly so that the film hugs the top and bottom loop-former.  By trial and error you’ll find the correct position for the sprockets,  and now fully tighten their grub-screws.  With loop-formers still closed, check the movement by winding the film by hand,  and finally by running the camera normally. Also check that the auto-threading feature works OK.  Now release the loop-formers and run the film at fast speeds to see that all is well.  Pristine unused film is best so that you can determine whether or not any damage occurs.  If it does,  it’s a simple matter to find the cause,  ink-marking the stationary film at various places along its path before you withdraw it from the camera.  An old projector lens is ideal as a magnifier.  Examine each perforation and its environs very carefully.

Next time we’ll look at the viewfinder mod.  Currently I’m  still tackling this !

to be continued…..

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Dunkirk in Imax July 29, 2017

(photo: Kathy Palmer)

If you get the chance,  do see Christopher Nolan’s  DUNKIRK in Imax. I found it stunning,  and the audience obviously thought so too. They clapped at the end.  And before the show, the manager of the BFI Waterloo Imax cinema gave a short introduction.  With arms outstretched he held up a 24-frame length of 70mm film,  with 15 perforations to each Imax image: they run horizontally.  That’s just one second of screen time !   He was keen on putting on more 15/70  presentations,  a refreshing attitude.  At present the digital Imax is 4K resolution on a smaller screen.   And the adverts we had been forced to watch (too large in my opinion) were only 2K,  he pointed out.  There was glee in his voice:  “Now you’re going to see 18K ! ”

 

As for the film,  great acting from Kenneth Branagh and Mark Rylance and others.  Very realistic sea and air action.  Fantastic sound effects.  Effective music…  Do see it.  I don’t think it will look much though on a small screen.   However,  another alternative is traditional 5 perf 70mm projection.   Indeed,  most of the sparse dialogue was done in 5 perf 65mm,  with black bars top and bottom of the huge Imax screen.   A similar method was used in Nolan’s previous movie INTERSTELLAR  but that was 35mm anamorphic. This time it’s less distracting.  Why not shoot dialogue in Imax ?  Apparently the cameras are just too noisy,  and Nolan doesn’t like adding dialogue afterwards.  However,  the close shots of pilots radioing were seen in full Imax:  their mouths were covered and not visible !

 

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Converting a Bolex H16M to Ultra-16, part 1 June 5, 2017

For some years now I’ve owned a little-used Bolex H16M camera, and had a yearning to modify it to Ultra-16.  Whenever I attempt something like this,  I first satisfy myself that the camera’s  registration is rock-steady. See  https://filmisfine.com/blog/how-steady-is-your-movie-camera/

Having no turret like most Bolex’s,  it’s quite easy to get started on the job.  It goes something like this….

Remove the leather and nameplate to expose the lens mounting plate.   Put the camera out of springwound mode and ready for backwinding.  Use the backwind key to take the shutter away from the gate area.   Remove the 4 big outer screws and gently ease off the lensmount.  Unlike the more complicated Bolex models, there’s no problem upsetting the timing.

Inside the camera remove the back pressure pad.   Unscrew the gate mounting-plate,  but as a guide for replacement its a good idea I think to firstly mark around the edges with a scriber.  Now remove the 4 small screws that hold the gate, and slide it out gently from between the side leaf springs.  It goes without saying that the gate must not be scratched at all.  Don’t  remove the top and bottom bolts.

The gate needs to be enlarged sideways to bring it out to 1.85:1  ratio.  The area between the perfs (by the frame-line) that is seen in Regular-16,  won’t be visible.  Although of course the image carries on being formed in this area,  so it is possible to use the camera normally as well.  1.85:1  is the same ratio as 35mm widescreen, if you are thinking of blowing up to 35.  With my modification I decided to go wider than 1.85:1,  something approaching  2.2:1.  However, I knew I would run into problems with the latent edge markings appearing within the image area,  unless I could find film-stock without these markings.   1.85:1  though has no such problem.  I was also a little concerned that the wide gate might not support the film sufficiently and cause unsteadiness or lack of flatness.  But happily this hasn’t happened.  The final width is 13.3mm,  leaving only 2.7mm to support the film.

Now for the widening !  I used a chunk of wood that I’d  used on another U.16 job,  attaching the gate firmly with drawing pins cushioned with cardboard.   Over the top I mounted a magnifying glass,  and started filing away with a needle-file.   Lots of breaks is a good idea with this kind of intricate work.  You don’t want to jab the gate by mistake.  Later on I changed position and filed from below, see photo.  I also paid particular attention to the top and bottom edges to make a smooth bevel,  and rounded off the corner bits where the film would touch.  Afterthought:  it may have been safer to completely cover the gate moreorless with card, as surgeons paper over patients !  Finally, I  wrapped fine emery cloth around the file and worked with this.  Then to finish off, the finest emery grade.

I now placed the enlarged gate into the mounting-plate again and loosely put it in position.  Obviously it was also necessary to remove some metal from the front plate,  so I first scribed marks either side and then filed away.  This is quite hard steel.  After finishing with emery I cleaned everything thoroughly,  then painted all the filed parts including the gate edges,  matt black.  When satisfied all was OK,  I reassembled the gate into the camera,  in precisely the same position and making sure that none of the 4 screws protruded.   With the camera laying on its back,  I then eased the lens plate back into position,  making sure the claw was out of the way,  and then turned the backwind key.  All looked fine and so I replaced the 4 big screws,  tightening them diagonally. Then stuck on the leather.

Next I loaded some dummy film and ran the camera.  The movement looked fine to the eye.  How it really performed would be tested later.  When the gate was taken off black paint came off also,  so I touched up all this again so that the important light seal would remain.  This is how the gate and front plate looks now, with some film loaded.                                       to be continued….

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How Steady is your Movie Camera ? September 20, 2016

DSC00165Good registration is extremely important in a movie camera.  It’s a good idea to put it to the test,  next time you have a few feet of film to spare.

Set up the camera on a very rigid support.  Perhaps a piece of wood screwed to the underside of the camera and then clamped on to a solid table.  Find a magazine or newspaper and tape it to the wall.  Focus carefully,  then shoot about 10 seconds of film.  If it’s a super-8 camera that’s it. You’ll see the result when processed. Actually it’s best to wait a few days after it comes back in case the film is still ‘green’ with some moisture in it.   On projection you can easily determine  whether the camera is acceptably steady.  Adjust the projector’s framing so you can see the frameline between the images, and  watch the newsprint to see if it moves against the frameline.  If the frameline itself moves it’s probably an unsteady projector !    By  ‘acceptably steady’  I mean just that.  The design of the film cartridge and the way the film is transported through the camera gate,  normally does not give an absolutely rock steady image.  Individual super-8 cameras do vary however, and you could be pleasantly surprised.

With regular 8mm and 16mm you have the choice of a more critical test.   Because the film is normally wound on a roll it’s  fairly easy to wind it back and do a second pass.  So any unsteadiness between the two images will show up clearly.  If your film has backwind it’s very quick and simple (keeping the lens covered !). Without backwind the camera has to be opened in the dark and the film rethreaded.  Using this superimposition method it’s best to underexpose each pass by one stop, so the combination is correctly exposed.  It is not necessary to align the images exactly.  The idea is that the small print in the double image will dance around slightly if the registration is not perfect.  A vertical jitter could be due to the claw in the camera not working properly, or more likely the pressure pad needs adjusting.  Horizontal unsteadiness is usually due to insufficient pressure of the side springs in the gate, if fitted.  A 16mm camera in good condition should give a rock steady image.  8mm cameras can be very steady too,  but are not usually as good because the projected image is magnified much more, and also the fact that most cameras are not sprocket-driven.   The film is pulled through the gate only by the action of the claw.

Once you are clear about how steady your camera is,  you will know its limitations if they exist.  A camera with less than perfect registration should not be used for intricate superimposed effects, and it may  not  be too good for static shots on a tripod.  On the other hand  it will likely look fine for handheld shooting,  as the natural movement in the image camouflages any unsteadiness in the camera transport.

 

 

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