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chuck colburn

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Posts posted by chuck colburn

  1. I would absolutely suggest that you do NOT try to fix this yourself. These elements are mounted with great precision and I doubt you could get it back together again properly. You can send it to a local repair facility for an estimate before committing to do the work. We can do this for you, and there are other places as well.

     

    What Mitch said. Also I don't know how long it's been like that but if there is moisture in there you should have it looked at ASAP as that can lead to fungal growth which can spread and eat the coating off of lenses and worse.

  2. I don't know how long of a focale length you can get away with on your shot, but if you can get the mirror close enough to the camera and use a smaller mirror here's one that might work for you. It would be best as you say to use a front surface mirror that's optically flat to avoid certain optical problems. Large first surface mirrors are rare and very expensive.

     

    Good luck,

     

    http://www.surplusshed.com/pages/item/l3602.html

  3. I need a ARRI II C eyepieces where can I get one anyone help me?

    I also need a arri IIc flat base and aI want chage the arri bay mount to PL

    I know P+S can rebuild it But can I buy a rebuilded PL mount and can I change it my self?

     

    Hi Jizhong,

     

    Eyepieces show up every so often on ebay. So far as changing you 2C to PL mount, it's fairly complicated as you need to completly replace the three hole turret with a new front end. This requires a teardown of the whole camera and then milling part of the camera body itself to provide clearance for the PL mount assembly. After that you need precision measuring equipment and an autocollimator to assure proper flange focale depth and parallelism of the lens mount seat to the film plane. That is to say it's not just a bolt or screw on operation.

  4. Quite right about the Nikon mount, it also has a quick-set mount on one port which is handy for the Mitchell-mount lenses.

     

    My reference to the 2709 was more about the shape of the turret, I've never seen a Mitchell with this 2709-ish turret. I've only seen the more common round disc set into the square standard. I suppose this turret design accommodates the data port.

     

    The other cool thing is the tach, which is part of the shutter-angle control assembly on the rear. Although it does interfere with the mounting of the standard ac/dc variable speed motor (the motor's tach bumps into the shutter lever if it's set anywhere above 50-degrees or so) My solution was to just remove the tachometer from the motor, although this camera will be used primarily for hand-cranking fun, so the on-camera tach is handy for that! I'm finding that the 2-turns/sec for 16fps is pretty easy to hit and maintain though :)

     

    I'd love to see a B&H movement up close and in action; the guts of any Mitchell are just awe-inspiring in their precision and simplicity!

     

    This is a fun site.

     

    http://www.cinematographers.nl/CAMERAS1.htm#bell

  5. Hi Marc-

     

    It has the plugged hole: here's (I'll try at least) a terrible photo (from the original seller):

     

     

    That turret hole on top looks like it might be a Nikon mount conversion. That little tab sticking out on the top looks like a lens release lever which you would have to press to release the lens. The Bell & Howell 2709 is a fixed pin shuttle movement as opposed to the Mitchell sliding pin registration type movement.

     

    Chuck

  6. The future of cinema will be stereoscopic.

     

    Steroscopic cinema requires a stereo base of 70mm. Or you will get wrong scale ( doll house effect )

     

    It is hard to get two 35mm sized sensors and lenses that close.

     

    Also, you want everything in focus, ie the exact opposite of what seems to be an obsession with "narrow 35mm-like dof".

     

    This means all 35mm cameras, 35mm sensors and 35mm lenses will be useless once the stereoscopic revolution takes off.

     

    I think Red Two should be a dual 2/3" cmos or foveon, but digiprime-compatible.

     

    Thanks

    Joakim Sandstrom

     

    You should read up on current 3D shooting techniques. So much of what you have stated is just flat out wrong.

  7. Do you think the red dot pattern is a ghost reflection of the sensor on the backside of the OLPF?

     

    Yeah that thought passed thru my mind also. I take it this is one of the first batch cameras that has been recalled. Someone at the RED site said the OLPF is at a spacing of 8mm from the film plane on the replacements but he wasn't sure if that was different from the originals.

  8. why would the FFD change? It screws right in yes? I dont think polishing the burrs off the edges of teh enlarged aperture would do much.. would it? Anyway the guy that filed my plate said that I should use a polishing stone

     

    Ah, you might not want to use a polishing stone even one as fine as an Arkansa (sp.). There is always the chance of picking up a bit of grit and causing more harm than good. The only thing we ever used was a polishing wadding called "Neverdull". Besure your hands are clean and the work area is also clean then pull a chunk of the wadding from the can and proceed with the polishing. Never scratched anything with this method. Even worked good on that soft German silver on the film guide in the bottom of the Arri 2C bodies. You can buy "Neverdull" at most hardware stores and even some drug stores.

  9. As the cameras age the available current probably is reduced.

     

    The camera still works but there is less and less efficiency. So using fresh batteries

    is a good idea however the increased load on the camera could mean that the lubrication is

    no longer doing a good job enough in cold weather.

     

    Yes Alessandro that could be quite true. Oil based lubricants do dry up as time goes by and can become stiff at lower temps.

     

    Chuck

  10. Isn't half the point of a framing chart to note and record any slight difference in that regustration between the groundglass and the negative?

     

    Yep it is. But by comparing the gate to the GG you can correctt any errors by adjusting the position of the GG.

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