Is f/ 1,000,000 a Possible Aperture?

In article , Alan Browne
writes
Nicholas O. Lindan wrote:
We get all goosy about f/22 and tighter beginning to have difraction
effects where large format photogs have no qualms about f/64...
The aperture of diminishing returns varies with format. From
testing
I have found:
Format Optimum aperture - where closing down
any more makes things visibly worse
35mm f8

Lens focal length didn't seem to have a lot to do with it.
As always, YMMV.

Certainly. With some of my 35mm lenses peak measured sharpness is at
about f/16 and others at somewhere between f/8 and f/11.

Assuming it is not a DoF issue (and I know you are smart enough not to
get confused by this), maximum sharpness at f/16 is not a good advert
for the lens in question. A really outstanding lens for 35mm (which
includes most top enlarging lenses) will give best resolution at f/5.6.
A merely very good or good lens will peak at f/8. For a lens to have a
(necessarily lower) resolution peak at f/16 suggests poorly corrected
aberrations.

Of course, contrast may improve a stop or two down, and this can
sometimes make the perceived sharpness increase on a cursory
examination.

David
--
David Littlewood

David Littlewood wrote:
In article , Michael
Benveniste writes
On 11 Nov 2006 20:04:58 -0800, "thebokehking"
wrote:

f/1,000,000 is possible, but the Rayleigh diffraction limit would be
on the order of 1.4 line pairs per meter.

t/1,000,000 is more realistic, but you'll need a fairly opaque filter.

Here's a shot taken of the sun with an exposure time of 43528320
seconds. But the sensor was for neutrinos.

http://cosmicvariance.com/2006/10/13/sun-shots/

I do like the idea of using the whole earth as a neutral density filter!

Great link, thanks

David
--
David Littlewood

Strange shot. Thanks for the link, Michael. Deserves to be the cover of
a magazine "Neutrino Daily"? "Arizona Skyways"? "Nippon Muon"? ;-).

When I clicked on the "Super-Kamiokande" Wikipedia link I got...

"Super-K is located 1,000 m underground in Mozumi Mine of the Kamioka
Mining and Smelting Co. in Hida city (formerly Kamioka town), Gifu,
Japan. It consists of 50,000 tons of pure water surrounded by about
11,200 photomultiplier tubes. The cylindrical structure is 41.4 m tall
and 39.3 m across. A neutrino interaction with the electrons or nuclei
of water can produce a particle that moves faster than the speed of
light in water (although of course slower than the speed of light in
vacuum)."

What particle can move faster in light in water (or any other medium
while we're at it) - a tachyon? a chronotron (if such a particle even
exists)? What, and even more important _why_can a particle travel
faster than light? Wouldn't a faster than light particle either a)
violate the laws of physics - "186,282 mps, its not just a good idea,
its the law!" ;-)) or b) travel backwards in time and therefore be
unmeasurable from our forward moving time frame and/or c) be its own
gran' pa'? ;-)

I'm not up on my physics so perhaps somebody who has that bent could
explain it to me...

With faster than light particles could I take a picture before I even
snapped the shutter or just photograph a younger me?... ;-) If I factor
in an f/1,000,000 stop's reciprocity failure with current film using
faster than light particles to make the exposure will I get my 1982
"Test Drive A Leica" Leica back? Will Kodachrome 25 magically reappear
in my camera?

"David Littlewood" wrote

A really outstanding lens for 35mm (which includes most top enlarging
lenses) will give best resolution at f/5.6.

That is what I was expecting ... that Summicrons and Micro-Nikkors
would be best at ~4-5.6 and cheaper lenses at F8+. Surprisingly it
was f8 across the board. There was some variation but it was on
the level of noise in the experiment.

Of course, contrast may improve a stop or two down, and this can sometimes
make the perceived sharpness increase on a cursory examination.

Well, perceived sharpness when reading an AF resolution chart
image on a Tech-Pan negative with a research microscope
was the methodology. There was quite a bit of judgement doing it
this way: eye fatigue, the effect of lunch and coffee.

--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation: F-Stop Timers, Enlarging Meters
http://www.nolindan.com/da/index.htm
n o lindan at ix dot netcom dot com

In article t,
Nicholas O. Lindan writes
"David Littlewood" wrote

A really outstanding lens for 35mm (which includes most top enlarging
lenses) will give best resolution at f/5.6.

That is what I was expecting ... that Summicrons and Micro-Nikkors
would be best at ~4-5.6 and cheaper lenses at F8+. Surprisingly it
was f8 across the board. There was some variation but it was on
the level of noise in the experiment.

Of course, contrast may improve a stop or two down, and this can sometimes
make the perceived sharpness increase on a cursory examination.

Well, perceived sharpness when reading an AF resolution chart
image on a Tech-Pan negative with a research microscope
was the methodology. There was quite a bit of judgement doing it
this way: eye fatigue, the effect of lunch and coffee.

Hm, maybe just enlarging lenses then... There are two factors I suppose
tilt it this way: (1) the magnification factor makes diffraction effects
much larger in this application, and (2) enlarger lenses tend to be
optimised for a limited range of conjugates, whereas camera lenses
require to work over a wider range.

Microscope lenses, which of course are designed for use at a fixed
object distance, give maximum resolution wide open. I suspect process
lenses are similar, but these are outside my experience.

David
--
David Littlewood

David Littlewood wrote:
In article , Alan Browne
writes

Nicholas O. Lindan wrote:

We get all goosy about f/22 and tighter beginning to have difraction
effects where large format photogs have no qualms about f/64...

The aperture of diminishing returns varies with format. From testing
I have found:
Format Optimum aperture - where closing down
any more makes things visibly worse
35mm f8


Lens focal length didn't seem to have a lot to do with it.
As always, YMMV.


Certainly. With some of my 35mm lenses peak measured sharpness is at
about f/16 and others at somewhere between f/8 and f/11.

Assuming it is not a DoF issue (and I know you are smart enough not to
get confused by this), maximum sharpness at f/16 is not a good advert
for the lens in question. A really outstanding lens for 35mm (which
includes most top enlarging lenses) will give best resolution at f/5.6.
A merely very good or good lens will peak at f/8. For a lens to have a
(necessarily lower) resolution peak at f/16 suggests poorly corrected
aberrations.

Just looking at a variety of MTF charts (various manufacturers measured
independantly by photodo or Chasseur D'Images) that show peak sharpness
is at anywhere 'tween f/8 to f/16 by lens manuf/FL/speed (and FL for
zooms). Often the curve from f/8 to f/16 (ish) is flat enough as to
really not matter; and for that matter, not significantly sharper than f/8.


--
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-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: Remove FreeLunch.

thebokehking wrote:
Scott W wrote:
thebokehking wrote:
Scott W wrote:

SNIP

The other thing that is very hard to get use to is looking through the
hologram and reaching around to the object that is still there. If you
are only lighting up the hologram and not the object you can see the
object right where it is and you can feel it right where it is but you
can see your own hand, this is very unsettling.


Why is that unsettling? -- wouldn't it be more unsettling to see your
own hand grasp for the (holgraphic image) object and grasp at nothing
but air?

The other thing that is fun to do is take a hologram with your hand in
it. For an object to show up in a hologram it has to stay still to
less then a wave length of light during the exposure. I would expose
anywhere from 5 second to 1 minute so there was now way for you hand to
say still, even 1/1000 of a second would be far too long. The result
is that where you hand is just black, a void. But the void is
three-dimensional. You can't see through it but there is just
nothing there, it is like a bit of space has been removed.

Scott

That would have to be a pretty slow piece of film (I.S.O .0003 ;-) or
you'd have to use a pretty dim laser and/or you'd have to place
somekind of ND filter in front of the laser (and/or the film?) that
wouldn't get fried by the heat of the laser. I've heard there is such a
thing as either white light or rainbow holograms that are viewable
without? a laser source? but for taking the original hologram, what
would youdo to get such a slow exposure?
The film (well plates) had an ISO of about 0.04. I was normally using a
laser that had an output of 20mw or so. The object I would shoot would
be up to a foot or two across, so it was pretty dim illumination. In
fact the hologram was often much brighter then the object.




If some kind of new technology semi-transparent plasma/LCD/LED/silicon
etc. _recording_ media could be used (and later viewed) instead of
film then are "digital holograms" a possibility or not enough MP of
data would br available through this new "digigram" process to
reconstruct a sufficiently detailed enough interference
pattern/wavefront to generate the holographic image?
The holograms I made were on 4 x 5 glass plates and the interference
pattern that was being captured to make the hologram was on the order
of 500 line pairs /mm to 1000 line pairs /mm. Figure you need two
pixels / line pair and you are looking at least 1 MP / mm^2, or about
13 GP for the whole plate. But you really only need about 1 mm^2 for a
hologram to be useful so you could make a useful one with just 1MP.

One of the demos I would do was to drop the glass plate and have it
break in to many small pieces. You could pick up any piece and shine a
laser through it and get an image of the whole subject. Different
pieces would all give an image of the object but different ones would
show it from a different point of view.

Scott


What would happen if you shined a separate laser through each of two or
more pieces -- a room crowded with images of the same object seen from
different angles?

What would happenif you shined two or more lasers at different angles
through the same broken piece of the hologram, the same image
multiplied or multiple slightly different images?

How about shining two lasers sotheir light paths would
intersect/"interfere" at the same hologram (whether that was a brokne
piece of hologram or the full thing?

What would happen if you took/_exposed_ a hologram with multiple pairs
of lasers intersecting/interfering from multiple angles -- multiple
full images from different angles? a holomovie? a holoheadache? ;-)

Could multiple red, green and blue lasers used to interfere with other
multiple red, green and blue lasers form an equivalent white light
laser hologram or would you need a whole spectrum of multiple lasers at
slightly different frequencies from red to green to bluue to accomplish
this if it is even accomplishable at all?