I always watch National Geographic movies and question myself: if you put a camera on the back of a seal, a penguin or some other underwater animals, does the animal even notice it, and does it hurt the animal?

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• How many megapixels would it have?
• What would its resolution (dpi) be?
• What would its ISO range be?
• What would its colour depth be?
• What is its focal length? How does it's field of view and depth of field compare to a standard 50mm lens?
• The eye doesn't zoom, but does the brain do any of this for us? Its seems like it when concentrating on something or if something attracts our attention.
• At what speed can an object pass the eye before it appears blurred? Ie "shutter speed" equivalent.
• How many "frames per second" can it process?
• I believe the brain compensates for white balance? Does the eye have a natural "default" white balance setting which the brain then compensates for?

My physics teacher claims that a very good slr camera is better than the human eye.

However I can't believe this is true. His argument was: If you stare at a single word in the centre of a page of a book, you wont be able to read the first word, whereas if you took a photograph you would quite easily be able to see every word.

Furthermore, if anything really was better than the human eye, how on earth would we be able to tell that it is better?

If a camera was placed 1 light year away from Earth with a high enough definition, could it be used to spy on events that took place on Earth one year ago? And, if so, could this technique be used to record our past by sending an array of such cameras to the appropriate distance in order to capture momentous events in Earth's history?

Jon King, Swindon, Wiltshire, UK

I've heard from a few sorces that we can now input computational images into the eye. The sources didn't go into much detail on how to do this, but I am buessing that they figured out how visual images are processed through our Optical Nerve, and - after some lengthy reasearch - were able to imitate these electrical nerve pulses and hook up a wire directly into the part of the brain which processes images.

Is this right, and if so, then why does it work? Shouldn't the patient feel some sort of electrical current flowing throught their brain? Why does the patient's brain recieve the image as if it were a normal image from out eyes?

When I charged a flash camera beside a radio set to AM, I noticed a series of sounds produced, similar to that of the harmonics of a sliding square waveform with frequencies above 16000 Hz. How do they interfere and what part of the camera generates radio waves?

Surely for the level of accuracy it seems to offer, it would need far more cameras than appear to be present at major tennis tournaments. Yet everybody happily accepts its rulings. How does it work?

Franco Pallatini, New York, US