Just had a really cool idea. Fiber optic taper

robertwerden

robertwerden

Well-known member
A fiber optic taper is a fused bundle of fibers that project a small image and project it to a larger image.

It is used to assist reading as seen here.
taper.jpg


The sizes can be custom made and if one was to have one made that went from 35mm to 80mm with a image flipping prism at the 35mm end, you could make a 35 mm adapter with no motors, focusing screen or other lenses.

Further you would not loose light due to the focusing screen.

Another point is you would not need to zoom in the lens because the fiber optic taper would be as wide as the main lens.

southbridge-2.jpg


So what do you think
 
Very interesting... I wonder if it would be up to the task optically. That first picture looks like it doesnt distort though... Pretty cool.
 
I would think it would be heavy. Solid glass about the size of a can of soda.
I wish they were cheaper so I could just buy one for experimenting.

All things considered, if it works, the price would be less than commercial adapters and if the image is clean and has no loss of light it would be ideal.
 
Reading up on some of the properties of these fiber optic tapers. It seems when going the other way, minimizing, you actually gain light rather than lose it.
 
robertwerden said:
The sizes can be custom made and if one was to have one made that went from 35mm to 80mm with a image flipping prism at the 35mm end, you could make a 35 mm adapter with no motors, focusing screen or other lenses.
Click to expand...

A flipping prism assembly can't be placed at the 35mm end because the back focus distance of the taking lens is too short (approximately 2" for SLR lenses). You could flip it at the 80mm end but that would be some honkin' big prisms!

Further you would not lose light due to the focusing screen.
Click to expand...

Fiber optic tapers do lose light, in two ways: 1) For the tiny fibers to transmit light, they must have space between them (cladding). So there is a percentage of the image area that transmits no light. This is typically 30% of the area, so they initially lose about 1/3-stop. 2) There is light loss due to "leakage" of light between the fibers. This not only causes light loss, but also can soften the image a bit and reduce contrast. The FOTs work best for light that is perpendicular to the front surface--such as a magnifier resting on a flat page. When you use them with a lens, the losses go up because the light rays that come in at angles from the lens are more likely to 'leak' between fibers.

But the main problem with them is what is called "chickenwire."
When they are made, small of groups of the tiny fibers are fused together, then those groups are fused into larger groups. This continues until the desired overall diameter is reached. Where the bundles are fused together, discontiguous lines are created--they are essentially imperfections in the fusing process. If you connect a camera to a FOT, these form a large array that makes it look like you are looking through a chain-link fence (or a chickenwire fence). (I have done this.) This is inherent in the manufacturing process.

You could, of course, try to vibrate the FOT to mask the chickenwire the same way vibrating ground glass masks the grain, but because of the weight of the FOT, that would be really difficult, and even if you got it to work, the whole camera and tripod would probably vibrate too...
And then you'd be back to a system more complex and more expensive than current adapters.

FOTs are cool though, and some camera manufacturers use them directly bonded to the surface of the CCD, but only for uses where the chickenwire pattern doesn't matter (surveillance, night vision, scientific applications).
 
Seems like it is well worth a shot if I can get my hands on one to play with. There are cheap ones and there are expensive ones. Looks to me like there are solid glass, and solid acrylic as well.

Im well versed on acrylic and I know if you warm acrylic up you can spin it on a lathe and shape it like a potters wheel. If acrylic is used then there is probably a way for me to fashon one being I work with acrylic in my business.

I have to research how acrylic is used to form a fiber optic line first though. As far as I know stock acrylic has no properties that permit it to act like fiber optics.
 
They are indeed promising...but light loss is in the order of four stops, contrast suffers (see the previous post on light leakage), and dead pixels (black spots) are quite common due to collapsed fibers. Some manufacturers use black fibre matrixed in to increase contrast and this contributes to the imaging problems. These are problems that have not been overcome in manufacture to date. Don't ask how I know this :-)
 
So what would be a correct size from the front to the back?
After looking around. The prices of these are unbelievable. Better off building a 35mm and sucking it up.
 
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