dan kessler

Don't want to delve too far into something at which I'm no expert, but there is one variant that does not have a Bayer pattern. The foveon chip, which is utilized in Sigma digital cameras, is an RGB design whose construction is similar to film itself. It is a layered arrangement with no offset. It delivers stunning images with absolutely none of the artifacts associated with the Bayer pattern. I often wonder why it hasn't made a bigger splash. They don't seem to market it very aggressively.

If you are familiar with basic lens geometry, then you can understand what diopters do. You know that parallel lights rays coming from an object at infinity pass through a lens and get focused to a point at the lens focal length on the other side. That's where the image is formed. However, this arrangement works in reverse, too. Think of a diopter as a lens working backwards. Light rays from an object one focal length away from the diopter will pass through the diopter and emerge as parallel rays on the other side. When these parallel rays now enter the main photo lens, they get focused just as they would if viewing an object at infinity. So, anything that is one focal length away from the diopter will be in sharp focus. Closer or farther, out of focus.

A lot of people have undertaken the challenge of building their own film scanner. Some have posted here before. Among the basic requirements are repeatable film registration, consistent illumination, and the transport system you already have been thinking about. Not to mention the computer and software that drives it all. Suffice it to say that building (or modifying) a film scanner is a major engineering project, which is doable, but only if you have the knowledge, skills and tools to do it. Not saying you shouldn't try, but the impression I get from your post is that first you are going to have to spend a huge amount of time and money acquiring the latter before you end up with something that scans any of the former.

Like Tyler said, this would not be a good choice for live action. Camera was built for a film recorder, as described below. 35mm Stein Mitchell VistaVision camera, serial number 10. This VistaVision camera shoots 8 perf frame 35mm film, as opposed to the standard 4 perf 35mm film and provides a large format original for feature filming. It is called a Stein Mitchell because it was built by a Mr. Stein and utilizes a Mitchell movement, except that the stroke is 8 perfs rather than four. It certainly runs 24 frames per second, but because the frames are twice as big that means that film is moving through the camera at 180 feet per minute, rather than 90 feet a minute. The camera was owned by Digital Effects Inc.; the company purchased the camera in 1981 and used it as a single frame transport to film on the Dicomed, a CRT color film recorder. All of the sections Digital Effects produced for the original TRON were made using this camera. Digital Effects purchased the camera from Murray Learner, who used it for shooting some of his features. I do not know how he came to own the camera. Likely it was made in the 1950s, when the VistaVision format was introduced. It does not come with any lenses or live action motor, it does come with a single frame stepping motor. We do have Mitchell magazines which we could sell in addition to the camera. Most certainly the camera runs at full speed flawlessly. MORE INFORMATION: In response to questions, we wish to report that this movement has two (not three) registration pins with one claw with (obviously) a very long stroke. The shutter appears to be a single blade of approximately 180 degrees. And yes, the camera is a rackover. Weight with the case is 72 pounds. Mark in Salt Lake City (ebay ksa50) advises that he owns an earlier one of these camera and that he has drawings he acquired from ILM to convert the camera to reflex operation and we will be happy to pass along his contact information to any purchaser of this camera (although his plans are not part of this offering). He also ads a bit more history about this instrument "There are less than ten of these cameras still in existence. Originally it was a camera built for two color cinematography known as Fox Nature Color. It had a largish lens that was actually a dual lens. Kodacolor filters snapped in the front half of the lens. Believe it or not the Stein Machine Company is still there in Rochester and the great Grandson has one of these cameras in original condition."

When using an incident meter, you want to aim the sphere towards the camera, not the light source. There are numerous resources on metering techniques to be found online

I'm no authority on underwater photography, but shooting from outside a tank seems like it ought to work. The camera lens is shooting through a transparent barrier either way.

I don't think you can mix cloud tank elements with the live model in the same set-up. Each type of water effect is quite beautiful, but you have two entirely different scales, each working best with different frame rates and lenses. Cloud tanks rely on the illusion of scale, making us believe little puffs of ink or paint are gigantic clouds in the sky. A live model in the same tank would reveal the true size of the paint squirts. Also, those tanks rely on a stable, calm volume of liquid, sometimes layers of static liquids with different densities. Too much turbulence would just muddy everything up. Plus, the technique is very labor-intensive, requiring numerous retakes, with a fresh tank of water each time. Oh yeah, and the model probably wouldn't like it, either. Shoot the elements separately.

Remember when those photoelectric signals were called 'video?' We digitized them so computer chips could process them.

Can't cite the specific source just now, but I'm certain that I read that the sensors in digital cameras are in fact analog devices. It's the outboard circuitry that digitizes the signal. Pretty interesting, eh Tyler?

Can't the seller tell us?

Art directors are not threatened by the digital revolution. Virtually every cg feature you see employs one or more art directors. They play a very significant role in the look and design of the entire film. They usually come from a strong fine arts background and have very impressive portfolios.

All you need to know is the distance from the camera to the green screen. Just calculate based on your field of view. However, you don't necessarily have to fill the whole frame with green. If you just want to extract a matte for your foreground subject, the screen only needs to be big enough to put a green border around that subject. Everything else can be garbarge-matted out.

So with regard to your motion blur question, the answer is no, the amount of motion blur will not be the same when shooting at different frame rates with a film camera. As you increase the frame rate, the exposure time decreases, so the amount of motion blur also decreases.

Ray tracing is probably the oldest and most fundamental cg 3d rendering method that exists. To be slightly more specific, rays are computed for each pixel in an image. There are other rendering schemes, some much faster, but ray tracing is good for photorealism and accurate shadows and reflections.

We tend to talk about lens properties such as focal length and image plane in absolute terms. We visualize a cone of light from a lens coming into focus at an exact point. Ideally, the film or sensor is positioned at that point, rendering the sharpest possible image. However, there is a margin of error, a deviation from that exact point, that our eyes will allow, yet still perceive as sharp. The light cone can overshoot or undershoot the plane of exact focus, producing circles, rather than points. The maximum allowable circle size that we still perceive as sharp is called the circle of confusion. It is this concept that gives us depth of field, or a range of perceived sharpness, rather than just a single plane. For 35mm motion picture film, I think the maximum allowable circle size is approximately .001 inch.

A magnifying glass IS a lens. They are usually double convex in shape. The hand-held type usually don't magnify more than around two times, so the focal length is probably around five inches. Infinity focus will be roughly one focal length away from the lens. The closer you get to a subject, the further you must move the lens away from the film plane or viewing screen to hold sharp focus. You can fashion a crude barrel out of cardboard and make it slip snugly into another cardboard sleeve to make a focusing mount. A simple lens of this type will suffer from a variety of aberrations, which will result in a soft, imperfect image. If you want to improve its performance, you will have to make a cardboard stop with an opening much smaller than its full diameter. Do some research on simple optics and you will understand the principles better.

Lens mechanics are what we make them. Helicoids consist of multistart threads with long leads, giving them a lot of linear translation for a little rotation. A normal thread is typically a single start with a much shorter lead. It will rotate multiple times to achieve the same linear travel.

Hate to say it, but there are no major effects studios left in Hollywood. You better include instructions on how to get work in foreign countries.

If you read the ebay item description, it plainly says it's for a Bolex 8mm camera.

If I'm not mistaken, no major studio even has a camera department any more. It's all contracted out.

Just need to confirm the exact angular position of the locating pin on a PL mount. Is it precisely 45 degrees clockwise from the top when facing the lens port?

Just some general info - AC synchronous motors in this application typically run on 110 volts, so 42 volts isn't a lot, really. Their main advantage is that they lock to the drive frequency and maintain constant speed. However, they don't have a lot of torque. You have to make sure the motor is big enough for the load. DC motors generate more torque, even though they run on less voltage.

Okay, there's another option I didn't consider before, because I've never used one myself. That would be a borescope. Just saw some demo stuff online that looked rather cool. They are routinely used to inspect gun barrels.

You say the original Bond opening was shot with a pinhole. Are you sure? I'm inclined to think it was a graphic element comped over the live action. In any case, you will probably get the best results using CG. No lens I know of can give you the extreme depth of field at the magnifications you would need for such small props. Plus, lighting the interior would be tough, to say the least. If you're going to go the practical route, you should consider a much larger prop. I wouldn't bother, though. CG can do it all.

Perhaps it is needless to mention the classic example of this effect as employed by Conrad Hall in 'In Cold Blood.' Here's a link describing how he did it, but no doubt you can find the info elsewhere. http://www.theasc.com/magazine/may03/cover/page2.html (a few paragraphs down)