Is it physically possible to have a lens with an f/1?

Iron Flatline · May 13, 2008

Battou said:
What mount is that .95 on?

I don't know what the original mount was (I believe a TV camera) but I bought one adapted to a Leica M-mount. It's weird, because the Leica M is a relatively small camera (esp. compared to SLRs) and the lens is as big as the camera.

Judge Sharpe · May 13, 2008

I suspose that given enough time and money, one could design a glassless lense of infinite apeture using a magnetic focus similar to what is used in electrom microscopes and x-ray machines. Used with a digital receiver, one could have atomic sized resolution and computer driven sharpness. I don't think that you could carry it around for snapshots, Think of the bragging rights- Want to see the molicules in her left butt cheek?
This day has been too long LOL
Judge

Alex_B · May 13, 2008

even electron microscopes do not really "see" single atoms. For example in HR-Transmission Electron Microscopy you see a contrast pattern, which is basically a density distribution seen through two Fourier transforms. you can tweak the focus that it looks a bit as if you could see atoms, or better, columns of atoms stacked above each other.
Some examples in here: http://prola.aps.org/abstract/PRB/v68/i1/e014115 or http://www.scientific.net/pdffile/24877.pdf but you need a subscription in order to see them I am afraid.

For surface techniques, such as Scanning Tunnelling EM you just see the tunnelling current due to the presence of the atoms while scanning the surface with a tip.

the wavelength of light will give you even more trouble giving atomic resolution

oh, and by the way, how would you focus xrays or light with magnets?

usayit · May 13, 2008

Iron Flatline said:
I don't know what the original mount was (I believe a TV camera) but I bought one adapted to a Leica M-mount. It's weird, because the Leica M is a relatively small camera (esp. compared to SLRs) and the lens is as big as the camera.

Canon 7 rangefinder had essentially two mounts built into one. The "inner mount" was a regular Leica screwmount. The "outer mount" was some sort of bayonet style mount. The outer mount was what the Canon 50mm f0.95 would attach to. IIRC, the same lens was also adapted for TV use as well. Since the lens to film distance is the same as the Leica, conversions are pretty simple given the know-how and machining ability.

There are a few people online doing the conversion. I considered that route (until I ran into a Noctilux that I couldn't pass up) and determined that the conversion was just under $200 which is a bargain in my book. A conversion for the TV version of the Canon lens cost slightly more.

http://www.camera-care.com/canon_f0_95_conv.htm

They pop up on ebay occasionally. I passed one up at my local camera shop a few years ago for about $1100. I tried to convince them to bargain a little on a packaged deal with the Canon 7 but there was little room for negotiations. Little regret...

Helen B · May 13, 2008

Here's a diagram of the Zeiss f/0.7 and the Canon f/0.95 50 mm lenses, not to the same scale:

Dubious Drewski · May 13, 2008

Insanity. I'm one of those that thought f1.0 was the theoretical limit until I came across this thread.

Thanks for enlightening me, guys. Now, time to go rent Barry Lyndon again. What a great movie.

Jedo_03 · May 14, 2008

is a pinhole camera f0...?

How about a highly specialised pinhole camera with "pinhole" only ONE MOLECULE wide... (of the material on the exposure side)...

I'm NOT a physicist (even if I CAN spell it..)
Jedo

Helen B · May 14, 2008

A wide aperture pinhole would not form an image - at f/0.5 it would be equivalent to just holding a piece of film towards the subject and expecting an image to form.

The theoretical limit of f/0.5 can also be arrived at by considering energy flow (the second law of thermodynamics), it is not set solely by geometrical optics. For example, if you had a true f/0.1 lens you could build a perpetual motion machine - the lens could create light energy from nothing. (in highly simplified terms)

Best,
Helen

abraxas · May 14, 2008

Jedo_03 said:
is a pinhole camera f0...?

How about a highly specialised pinhole camera with "pinhole" only ONE MOLECULE wide... (of the material on the exposure side)...

I'm NOT a physicist (even if I CAN spell it..)
Jedo

Other way. A pinhole camera with an aperture the diameter of a water molecule (10^-10 cm) would work out to be something like;

f/10^9 for a 10 mm focal length

In human;

f/10,000,000,000 for 10mm.