Optical Overunity Machine?

Back then and ever since, it stirred my understanding: How can this be? Whenever you attempt to amplify light, you need an external source of energy.

Or more light to begin with!

Doesn't it just mean that the lens has a larger aperture allowing more light into the lens, which is then magnified to a smaller area by the optics in the lens (in a similar way to a magnifying glass).

Its just taking more light and putting it into the same area compared to another lens which takes less light and puts it into the same sized area. Isn't it? No over-unity action here.

As ever, a down-to-Earth answer. That is just what it is. Just like a magnifying glass used to roast ants (don't try this at home or PETA will be all over your ass!), all you are doing is concentrating the sunlight from a larger area into a small area. No mystery or > 1 efficiency stuff happening here.

The spec is formalised as a ratio:"f1:0.96", "f1:1.2"or "f1:1.4" and it is supposed to evaluate the beam intensity compared on both ends of the lens, with smaller figure (always 1) to indicate for the input, and larger for output - of the lens - trasferring light to the sensor area.

f = focal lendth/diameter.

You can design the lens with lower f number also, only problem is in the end you may not get the picture. (the depth of field may go hayware)

Thst's why go lower in f number, the special shape of the lense will exponentially shoot up the price.

Isn't the "Focal Length" determined by the effective distance between the lens and the sensor ?

That is right but then suppose the diameter of the lense is more than the focal length and you fo full aparture ?

And then the focal length in a multiple lense is what you can play around for the effective focal length.

I am not sure about the technology, but all the f ratio must be just a bit more than greater than 1 (1.2,1.4,...) makes sense in the conventional curved lenses. These guys must be using unconventional profiles or may be some sort of internal reflections to effectively reduce the f (focal length) with respect to d.

As far as my experience is concerned, each f-step doubles (or halves) the light intensity of the previous step, so that they correspond to the same stepping system applied to shutter speeds, in a way that a step-change in the shutter-speed can be compensated by a corresponding change of the aperture, and vice versa, to remain in the same light intensity zone already achieved

That is right too, as I learnt long back through the canon AE1 manual -(still have that in working condition, the problem is getting the cell 4SR44 not available easily nowadays ) the one before the AGFA never had any setting just aim and shoot- I thing that was the advertisement catchword too .

But still f=1 does not mean that the whole light is passed through, it means that it gives an intensity twice that of 1.2 (or light intensity is total- what is total ?)

Any way whole light is ruled out since the lense glass despite all the coatings will reflect and absorb a bit.

So take the F16 rule and start doubling the aparture and halving the exposure to get the set value. That way you may land up in a lens that can have good exposure even for slow film speeds.

As mentioned in post #4, f=focal length/diameter.

For a concave mirror it is theoretically possible to get f=0.5 as the focal point is at half the radius from the mirror.

In practice, the spherical aberration becomes horrendous and a special curve is needed. I think it is some form of parabola.

Similar considerations are needed with lenses, and an "overunity" lens requires aspheric lenses and quite a collection of them to eliminate all the aberrations and give a good quality image.

I guess with parabolic shapes it may be possible to make a mirror less than 0.5. It would be interesting to see it, and even more interesting to find out how it would be made.

I'm not sure if there is a limit to what could be done with lenses.

The "overunity" f number doesn't mean that light is amplified, simply concentrated. The lower the f number, the smaller the image. The smaller image means more light is concentrated in a smaller space, hence the image is brighter.

To illustrate, project a 35mm slide on to a screen. (Does any one remember 35mm slides?). A certain brightness of the image will be noticed. Move the screen further away and you get a bigger image but the total light from the projector is the same so the image is not as bright.