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Bernie O'Doherty

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    Newark Valley, NY
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    Camera Tech/Engineer

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  1. Interesting point Chris. I'd like to meter both and see. Theoretically the wider lens would bring in more light, but practically that light has to pass through more glass to do the job ! Hopefully, a lens designer might be looking on....,and enlighten us !!
  2. If the adaptor is set to specs, everything should focus as it should. I would assume there would be a light-loss factor. In a pinch, you could measure the difference between the adaptor being on and off with your light meter behind the lens, and that would approximate the stop difference. I would guess a stop.
  3. Arri flange focal depth is the same for PL and bayonet :52mm. Unless the adaptors are off specs, you should not have a problem..........unless they're going on a Bolex. Then the lenses should have Bolex Rx mounts.
  4. Hi Giorgio, Chris is right about using the hand-held meter. Sure, the camera's meter may have worked well up until now, but it is so dependent on the battery voltage. The slightest voltage drop causes the electronic system to defocus from the extra bells and whistles ( meter, battery-check meter, zoom motor etc,) and focus on maintaining camera run speed. And a 30 to 40 year-old Cds light cell has lost a lot of it's original snap.
  5. The only way to do this (apart from hard-mounting a pl mount) is to use the c mount. Visual Products sells a c mount pl adaptor. You would probably need to support heavier lenses.
  6. Yes John, only difference is when you're in the darkroom, it's like you're in a giant changing bag with the mag and film. There's a movie idea there somewhere...... Cheers, Bernie
  7. It could be so many things : ! : The camera's flange focal distance may not be set at 17.52mm (non-reflex Bolex) or 20.76mm (Reflex or Rx Bolex). 2 : The groundglass may not be in the correct position. 3 : The lens/lenses may not be properly collimated to the proper mount distance regarding infinity setting, and 4 : The lens rear thread may be touching and thus moving the prism block, throwing focus off. Another factor to consider is the stability of the film in motion, and this would involve the claw transport and the pressure plate setting. Claw length and film gear alignment also play an important role in providing a focused image. A further consideration would be to ensure that you're using Rx lenses on a Rx Bolex , and "c" mount lenses on an older non-Rx Bolex.
  8. Hi Gregg, They're still rockin and rollin. They're in Paris and their phone number is: 33 01 46 66 7203. Good Luck.....Bernie O
  9. Yes, it's hard to explain, but you're holding one ring and turning the other. The one ring holds it in the right position on the lens front section, and then the other ring twists against the first ring in the opposite direction. It's all so counter-intutive. It's like one of those puzzles you see in bookstores !! Be patient, and common-sense and your brain will prevail ! Cheers and good luck.
  10. [The front portion of the lens fits on to the back portion ( the piece with the lens mount) in a counter-clockwise direction. Be patient and you will find the starting point by feel. Slowly turn the rear portion onto the back of the front portion until you feel it lock, then tighten the ring on the rear portion in a counter-clockwise direction.
  11. Hi Ken. Be careful of using 35mm lenses on you S16. Generally, the rear exit pupil in 35mm still lenses is roughly twice the diameter of 16 or S16 lenses. So a lot more light floods the camera interior, especially wider lenses. What sometimes happens in this case is that all that extra light reflects off interior camera areas that weren't designed to accept it. Somewhat like attaching a fire hose to a garden hose. The result sometimes ends up looking like flicker or giant light flares. Safer to film-test in outside bright light before any major shoot. Bernie.
  12. Depends on how deep the fungus has etched. Also, something that looks like fungus inside the lens could be a grease smear from the iris blades. If the fungus has just begun to break down the coating it might be possible to get away with it if it's not on the lens central axis. First thing to do is to bring Dracula into the light. Leave in on a sunny window ledge for a few days, let it get some good fresh air. It's been enjoying the darkness, humidity and stale air for 25 years. Sharpen up the wooden stake just in case..... Cheers, Bernie
  13. Joe, You could try removing the filter holder. Then flip the turret around so that you can get at the prism block. Pull out the prism so you can look directly through the aperture plate to the film plane. Release the spring tension by running the camera until it stops. Push in the stop/start button to the locked-on position. Slowly move the movement by turning the film sprocket gears by hand until you have a clear view through to the aperture plate. You should have a clear optical path. Look for a film chip somewhere, blocking the light path top-left, (shows on image bottom-right). Check that the prism block is clean and not chipped. Cheers, Bernie
  14. Hi Derek, Sounds like the feed side core adaptor plate is bent. Open up the feed-side door and watch the film in motion. It's probably probably being rubbed by the bent portion of the adaptor plate while in motion. Could also be the take-up side. Solution is to patiently unbend the plate by hand. Try flipping the feed-side plate to the take-up side to see if it helps. Good Luck, Bernie
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