Published : 6th May 2005
I am in the process of researching the purchased of a Mitchell camera for Time Lapse use. I understand that some of the models available have a drive mechanism which has bearings in the shaft. Does any one know which models in the Mitchell line are the best for this purpose.
>I am in the process of researching the purchased of a Mitchell camera >for Time Lapse use.
Any of the Mitchellâ€™s of the "standard" body type should work fine. These are all the Standards, Hi-Speeds, NC's, GC's, D's, and a myriad of other models, including even the old BNC's. Originally, these were all rack-overs, but there have been conversions to reflex, most notable by Fries. What you want particularly for time lapse and animation it to be sure the camera has the original focal plane shutter, as in all the rack-overs, and on the pelicle-type reflex conversions. If you want to use the adjustable shutter, be careful at narrow angles, because many are warn and sloppy, and this can adversely effect consistent by having the shutter angle vary frame to frame.
The spinning mirror conversions have an Arri type shutter and are not light tight through the lens port. If you use an spinning mirror type, you will need a capping shutter. Norris makes a great animation/time lapse motor that syncs to their capping shutter, and even to an exposure control device (though I don't like that).
I'm not sure about the bearings issue. All the Mitchellâ€™s I've opened up have bearings on the drive shafts...
The best source for Mitchell info in your part of the world is Ken Stone at Stone Engineering. He has lot's of Mitchellâ€™s for rent, and is very good at servicing them. If you want to buy one, you will need him or someone like him for service. His shop number is 661-242-8490, and, of course, all the usual disclaimers apply.
Gear+Rose Motion Control
>I'm not sure about the bearings issue. All the Mitchellâ€™s I've opened up >have bearings on the drive shafts...
I believe that the bearing difference is the difference between a Mitchell High Speed and a Mitchell Standard camera & movement. There are a couple of sets of ball bearings on the High Speed which are plain bearings on the Standard. This is not a concern, as far as I know, for time lapse work. Other more visible differences are the gear which drives the movement inside the box - on the HS it is metal while on the Standard it is fibre. Likewise, the large driving wheel on the motor side is fibre on the standards and I think it is brass on the high speeds.
Note that if you are purchasing a camera that was once used for animation, optical printer, or motion control work, it may well have had its flywheel removed. I do not know whether this will adversely or beneficially affect the camera's operation with an intervalometer, but it may affect shutter bounce when running at speed. Once again, Ken Stone would be a good person to check with on these sorts of issues. Shutter bounce, which is a situation that sometimes occurs when there is enough gear lash that the shutter can "bounce" or oscillate back and forth from being pushed by its gear to bouncing forward until it fetches up against the next tooth driving it...at some speeds, this can cause a cyclical repeating exposure variation - some frames get less light because the shutter is accelerating through the exposed part of the frame and some get more light because the shutter is "bouncing back" the other way during the exposed part of the frame.
I may not be explaining this clearly, but even if this sounds cloudy - it is worth asking whomever you are going to choose to check out your camera and maintain it.
EVEN AFTER YOUR CAMERA HAS BEEN CHECKED OUT BY A PRO, BE EVER VIGILANT IN LOOKING FOR LIGHT LEAKS!!!!
These are all old cameras and over the years many things have been attached and removed from many of them, leaving lots of little holes. When in doubt, tape the whole friggin' camera up with camera tape...including the joint between the mag and the camera box and all around the lens board.