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Alex Nelson

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  1. Alex Nelson
    The easiest way to use it with your camera is to pull the optical cell off its focus threads (which is much easier than it sounds) and attach it to an inexpensive focus helicoid. Another fellow did exactly that with a 75mm Baltar to use it with an EF mount. (http://www.cinematography.com/index.php?showtopic=67913&hl=baltar)
  2. Alex Nelson
    Baltars were sold in virtually every mount used between their release in the late 1930's and the release of the Super Baltars. For the most part, that means Eyemo, Debrie, Mitchell (almost all variations), Cameflex, Wall, etc. I have seen a single 40mm Baltar in Arri standard mount, but I don't think any of the three wider focal lengths (25, 30, 35) would reliably clear a reflex mirror. The 75mm, though, is guaranteed to work with pretty much any reflex system or mount because of its relatively long rear working distance. It also covers full-frame 35mm without issue (as do all Baltars longer than 35mm) and can give you a really pretty image if the glass is in reasonably good condition.
  3. Alex Nelson
    For AC's doing check-outs in rental houses, taping out lenses against the engraved scale is a quick way to catch back-focus issues. If you don't have accurate marks, you might find out too late that your lenses can't hit infinity. There are also many instances where you just have to pull off the marked barrel and there aren't monitors with peaking or wireless focus systems on hand.
  4. Alex Nelson
    The Red Pro Primes were not rehoused still glass. They were designed and developed by the team behind UniqOptics, in California. Kenji Suematsu, who was responsible for the mechanical design, talks about the process (and eventual lawsuit) for a few minutes in this interview: http://archive.densho.org/Core/ArchiveItem.aspx?i=denshovh-skenji-01-0022
  5. Alex Nelson
    Sorry, I should definitely have stressed the safe removal aspect of the process more.
  6. Alex Nelson
    I have an old Bardwell McAlister 2k that had a similar problem. The pinch ring that they used to hold the fresnel in place had a thick asbestos insulation around it that actually made contact with the glass. Most of it had deteriorated or rotted off by time I got it, meaning there was no longer enough pressure to keep everything secured. I carefully removed the rest of the asbestos and wrapped gaff tape around the metal ring instead, as a temporary replacement. I don't know for certain if the 751 had the same asbestos wrap, but it could account for the loose fresnel.
  7. Alex Nelson
    Pointing the eyepiece assembly at something like the moon will tell you if the objective/eyepiece are properly calibrated, but placing a mirror in front of the whole thing with the light source turned on will also tell you if your reticle is calibrated as well.
  8. Alex Nelson
    I apologize, my original instructions were not terribly clear. I have an LED flashlight on my Richter, so I was envisioning taking the whole autocollimator assembly (light source, eyepiece, and objective) into, say, a bathroom and pointing the whole thing at a mirror. The more reasonable method would be to just get a small hand mirror and place it in front of the objective without taking the whole thing off the rails. The rest of the process is the same.
  9. Alex Nelson
    There is an old Jon Fauer promotional/educational video for the Arricam system that featured the same effect. In that case he was showing off the Arricam's ability to ramp the shutter during an iris pull. Of course, that presupposes that the shutter angle changing wouldn't negatively affect the motion in your shot.
  10. Alex Nelson
    The quick and dirty way to check if the reticle is in its place is to mount one of the collimator objectives on the eyepiece and point it at a mirror while looking through (as though collimating a lens). Assuming the objective is properly calibrated, the reticle should look sharp in the eyepiece. If it isn't, then you have to determine whether the other objectives have the same problem. If they all look soft, then the reticle probably needs to be adjusted. If some are sharp and others aren't, then you need to decide which variables to start eliminating.
  11. Alex Nelson
    Swing by Technological Cinevideo Services (TCS) at 45th and 11th. They're relatively small, but they do huge shows (House of Cards, Mr. Robot) and a lot of big independent movies like St. Vincent. It's a very intense place to work, but after a couple of years there, you'll be in a great position to move into the field.
  12. Alex Nelson
    Cine zooms don't usually change focus during zooming unless the back-focus is off. If a lens is properly collimated to the camera, by shimming the mount on either the lens or on the camera, it should hold focus through the full zoom range.
  13. Alex Nelson
    The macro shots look incredible. It's such a clear, creamy lens. Glad you gave it a new life!
  14. Alex Nelson
    Not to stray too far off topic, but why do Australian crews prefer focus scales in feet and inches? I visited Vantage in Paris several months ago, and apparently French camera assistants have the same preference.
  15. Alex Nelson
    Any photos to share yet?
  16. Alex Nelson
    Hi David, I'd be interested in them, if you're still offering. I recently came across some AC issues of a similar vintage in a thrift store and they're an incredible reference for the equipment and techniques of the time.
  17. Alex Nelson
    The flickering in the finder isn't any better or worse than your average Arriflex, but you presumably don't have an AC pulling focus on an R16. Maybe somebody who's more accustomed to focusing by eye on such a viewing system would have sharper footage, but my eye tends to focus past the crosshairs and tricks me into thinking something is crisp.
  18. Alex Nelson
    Do you know, Simon, if the R16 viewfinder you described was common across all models? Mine seems to rely on the eyepiece diopter being accurately set on the crosshairs in order to judge focus. Even then, the flicker from the mirror makes it difficult for a single operator to confirm if the subject is sharp. My Pathe, which is a Professional Reflex-16 AT, has a viewing system that bypasses the shutter and offers a focusing screen with a microprism (or something that functions similarly), making it much easier to keep the subject sharp. I'm not familiar with any variations there may have been in each line of cameras and model to model, but between my two cameras, the Pathe has been more reliable for focus.
  19. Alex Nelson
    I have an electric R16 that was converted to Ultra 16mm and it is a brilliant little camera. It has a good range of speeds and absolutely purrs when compared to clockwork, wind-up cameras. I also have a crank-based Pathe 16mm newsreel camera and, between the two, I find the Pathe better suited to run-and-gun shooting. Its pellicle viewfinder is more accurate, focus-wise, than the Beaulieu. It doesn't flicker and offers a positive confirmation of focus which the Beaulieu doesn't. R16's have a nice, compact battery design, but you need to make sure that the batteries are reliable (likely recelled) and that the charger hasn't degraded too much. Wind-up cameras like the Pathe or Bolex obviously don't have that particular hurdle.
  20. Alex Nelson
    Kish Optics made the Mesmerizer. There was a front attachment for small primes and a rear attachment for zooms. Both had rotating cylinder lenses to accomplish that effect.
  21. Alex Nelson
    That's great! Were you able to keep the lens flat and parallel to the film plane? It's not as critical as with wide-angle lenses, but I imagine your jig probably held it reasonably straight. Can't wait to see what you shoot with it!
  22. Alex Nelson
    I don't know if you have any CAD experience, but you might try a service like www.shapeways.com to 3D print something more precise and finished-looking if your tests bear fruit.
  23. Alex Nelson
    The threads are actually imperial (Bausch and Lomb being a US company), and are an arbitrary 1.560" x 40 TPI. It's not likely you'll find a ready-made adapter to match that, but if you know a machinist or have a reasonable garage shop, you shouldn't have any trouble fashioning something to couple it to a helicoid. It's too bad yours didn't come with any kind of mount, since that would have the mating threads and would open the possibilities for adapting the lens without incurring too great an expense.
  24. Alex Nelson
    At infinity, the image would land about 60.30mm from the front of the silver threads on the back. That is, for these purposes, your flange surface on the housing.
  25. Alex Nelson
    There are lots of good books on lenses for photography and cinematography. The best, and most current, is called "Applied Photographic Optics", by Sidney Ray. It's a little pricey, but an enormous and thorough wealth of information.
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