I have a theory, optical physics related (pinhole optics)

[Nutrient]

Some of you may have see the pinhole method of seeing without having to use glasses.

My question is this, could this same pinhole application of viewing clearly be useful in optical microscopes? And if so, can it be used in series?

By my understanding the pinhole technique works by correcting imperfections in lenses, and limiting light pollution.

- A. Phelps (just thought of this a few minutes ago, sorry for the lack of data and intellect, and hello forum).

 

[Simon Bridge]

The pinhole method is not all that useful for seeing without glasses so the answer to the question is: not really.
Note: your understanding of how the "pinhole technique" works is incorrect. Where are you getting this information from?

 

[Nutrient]

What is the correct method of how the ""pinhole technique"" works?

And I disagree with your statement that the pinhole method is not all that useful for seeing without glasses.

I am getting my information from "my understanding" which I listed in my post. So you disagree that if limits the effect of an imperfect lens AND the effect of external light refracting in imperfect areas of a lens?

Also, "not really" is not the answer I am looking for.

 

[davenn]

I am getting my information from "my understanding" which I listed in my post. So you disagree that if limits the effect of an imperfect lens AND the effect of external light refracting in imperfect areas of a lens?

and so if you understanding is flawed, so will be your reasoning and theory

if you don't base your understanding on proven scientific methods, then you have a problemDave

 

[BOAS]

This video was uploaded yesterday by "MinutePhysics" - Could this be what you're referring to? Though your explanation is not the same one that's given in the video.

 

[Cthugha]

All the pinhole technique does is increasing the depth of focus, so it is useful in ophthalmology in order to check whether vision problems are caused by incorrect focusing of the eye or something deeper.

In imaging increased depth of focus always introduces some drawbacks. You will automatically limit your numerical aperture/field of view, the intensity you have and the magnification/resolution you can get. As resolution is what you want in microscopy, having a small aperture like a pinhole is not helpful at all.

 

[Nutrient]

and so if you understanding is flawed, so will be your reasoning and theory

if you don't base your understanding on proven scientific methods, then you have a problem


Dave

I thought there might be more theoretical physicists here, you guys as asking me to prove that outside light effects how much you can see when you have a telescope in your avatar? The pinhole would gather more information for the same reasons they build telescopes on Mauna Kea.

You do know that device uses the same scientific methods to work as my theory right?

 

[Nugatory]

By my understanding the pinhole technique works by correcting imperfections in lenses, and limiting light pollution.

It's not so much that it corrects imperfections as that it avoids them: If you can restrict the path that the light takes to just the center of the lens, where both sides are parallel to one another and the incident angle is ninety degrees, you don't have a lens at all, just a piece of transparent media in the way. However, this also reduces the light intensity dramatically, so you end up with a dim image and a narrow field of vision.

The only time that I've ever found the pinhole technique to be noticeably effective was on a snowfield at high altitude in bright sunlight - myopia much improved within the tiny field of view afforded by makeshift snow goggles, and ambient light levels so high that "dim" was a good thing - but not so much that I'd be willing to do without my prescription corrective eyeglasses.

My question is this, could this same pinhole application of viewing clearly be useful in optical microscopes? And if so, can it be used in series?

It's hard to see how it could be practical. It basically works by blocking all the light that we cannot focus effectively, whereas a microscope needs all the light it can get. That's why the emphasis is on better lenses so that we can make the best use of the light that we have.

 

[Nutrient]

All the pinhole technique does is increasing the depth of focus, so it is useful in ophthalmology in order to check whether vision problems are caused by incorrect focusing of the eye or something deeper.

In imaging increased depth of focus always introduces some drawbacks. You will automatically limit your numerical aperture/field of view, the intensity you have and the magnification/resolution you can get. As resolution is what you want in microscopy, having a small aperture like a pinhole is not helpful at all.

Take a look at the secondary mirror baffle on the Hubble telescope:

http://postimg.org/image/hlrst4rr1/2542d196/

Notice the small hole being the focal point:

Tell me again why having a small aperture like a pin hole would not be helpful at all? How would that effect resolution when mirrors are the devices collecting the optical information on a non-digital microscope?

 

[berkeman]

Take a look at the secondary mirror baffle on the Hubble telescope:

http://postimg.org/image/hlrst4rr1/2542d196/

Notice the small hole being the focal point:

Tell me again why having a small aperture like a pin hole would not be helpful at all? How would that effect resolution when mirrors are the devices collecting the optical information on a non-digital microscope?

That is not a pinhole. This is how pinhole optics work: http://en.wikipedia.org/wiki/Pinhole_camera

.

 

[Nugatory]

Take a look at the secondary mirror baffle on the Hubble telescope:

As that picture is drawn, the "pinhole" isn't doing anything for the focusing of the image; there's no light leaving the secondary that is being intercepted by the hole. As far as I can tell, it's there to allow the instrument package to be located behind the primary to maximize the uncovered and useful area of the primary. That has nothing to do with pinhole optics.

 

[Nutrient]

It's not so much that it corrects imperfections as that it avoids them.

It's hard to see how it could be practical. It basically works by blocking all the light that we cannot focus effectively, whereas a microscope needs all the light it can get. That's why the emphasis is on better lenses so that we can make the best use of the light that we have.

So could the pinhole method allow for a dramatically brighter light used to view a specimen?

Also, I found the name for "my" theory that already exists and has been proven "practical":

http://en.wikipedia.org/wiki/Confocal_microscopy

 

[Cthugha]

Also, I found the name for "my" theory that already exists and has been proven "practical":

http://en.wikipedia.org/wiki/Confocal_microscopy

Ehm...in confocal microscopy you focus onto the aperture. In "pinhole seeing" you place it into a parallel beam. I am not sure how much background in optics you have and the difference may not be obvious at first sight, but let me assure you that these are conceptually very different things.

 

[Nugatory]

Also, I found the name for "my" theory that already exists and has been proven "practical":

http://en.wikipedia.org/wiki/Confocal_microscopy

That is an interesting special application, and new to me - thanks. But note the limitations:
- "However, as much of the light from sample fluorescence is blocked at the pinhole, this increased resolution is at the cost of decreased signal intensity – so long exposures are often required."
- "As only one point in the sample is illuminated at a time, 2D or 3D imaging requires scanning over a regular raster"

 

[Simon Bridge]

What is the correct method of how the ""pinhole technique"" works?

I think the others have given a good description here - certainly not as you have described it.

And I disagree with your statement that the pinhole method is not all that useful for seeing without glasses.

You are free to disagree with what you like - corrective lenses are still much more useful than an array of pinholes.

I am getting my information from "my understanding" which I listed in my post.

Please explain how you cam by "your understanding" - what scientific principles did you use and what reasoning did you employ. This will help me answer your questions to your needs.

So you disagree that if limits the effect of an imperfect lens AND the effect of external light refracting in imperfect areas of a lens?

... no I don't.
Making sure the incoming light is limited will also limit the effects of the lens.
You also get a dim fuzzy image with doubling at the edges.

However - the short answer to your question is still: no - pinhole method not useful for microscopy.

 

[ZapperZ]

So could the pinhole method allow for a dramatically brighter light used to view a specimen?

Also, I found the name for "my" theory that already exists and has been proven "practical":

http://en.wikipedia.org/wiki/Confocal_microscopy

In addition to what Cthugha has mentioned about the difference between confocal microscopy with pinhole camera (and this is why you should have heeded the questions being asked as to where you got your understanding of the physics of pinhole camera from), the issue of light collection has been something you've ignored.

While making pinholes smaller will improve the "sharpness" of the image, you are also severely cutting the amount of light that reaches the detector/screen. If you are planning on using this for telescope (and you were using the Hubble as an example), this is a VERY bad idea. Most astronomical telescope tries to go bigger just so they can collect more light from extremely dim objects that are so far away. Cutting in the light unnecessarily here goes contrary to what they want to do.

So if nothing else, this is an extremely severe handicap to your "theory" IF you think of what it is meant to be used for.

Zz.

 

[Nutrient]

That is an interesting special application, and new to me - thanks. But note the limitations:
- "However, as much of the light from sample fluorescence is blocked at the pinhole, this increased resolution is at the cost of decreased signal intensity – so long exposures are often required."
- "As only one point in the sample is illuminated at a time, 2D or 3D imaging requires scanning over a regular raster"

Hubble uses long exposure too.

Here is the basic idea:

1. Limit viewing area to a small hole before the image is magnified.
2. This shouldn't effect how the lens works, it would simply lengthen the area between the focal point.
3. Use higher illumination to improve detail of resolution, taking advantage of the dimming effect.

About my background in optics, I am 12.

 

[ZapperZ]

About my background in optics, I am 12.

That is your age, not your background in optics, unless you are equating your age with the standard level of understanding that kids that age should have in understanding optics/physics.

If so, how were you able to understand "conformal microscopy"?

Zz.

 

[Nutrient]

That is your age, not your background in optics, unless you are equating your age with the standard level of understanding that kids that age should have in understanding optics/physics.

If so, how were you able to understand "conformal microscopy"?

Zz.

I'm not actually 12, haha.

But that would probably be about as much as I know, yes.

 

[ZapperZ]

I'm not actually 12, haha.

But that would probably be about as much as I know, yes.

Then my question still stands. You gave us a link to conformal microscopy to "support" your scenario. I question whether you actually understood the physics of such optics and why you would use it as a reference to back up your claim.

Please note that, unlike other science forums, this forum actually have real physicists, engineers, mathematicians, and other scientists. There is a good chance that if you are using an idea in physics to support your claim, that there's someone here who either knows the subject area, or have even worked in that area! So unless you know exactly what it is that you are citing as references, then I'd suggest you either ask for clarification, or try to learn from what you've been given. Otherwise, you will look very foolish when someone else points out that you didn't know what you are citing.

Zz.

 

[Drakkith]

Hubble uses long exposure too.

Here is the basic idea:

1. Limit viewing area to a small hole before the image is magnified.
2. This shouldn't effect how the lens works, it would simply lengthen the area between the focal point.
3. Use higher illumination to improve detail of resolution, taking advantage of the dimming effect.

About my background in optics, I am 12.

Resolution in a microscope depends on gathering as much of the EM wavefront as possible. Using a pinhole directly counteracts this and would do nothing but blur the image.

http://en.wikipedia.org/wiki/Diffraction_limit

 

[Andy Resnick]

My question is this, could this same pinhole application of viewing clearly be useful in optical microscopes? And if so, can it be used in series?

First, the 'pinhole method of seeing without glasses'. Yes, it works very well. By stopping down a lens (the pinhole is located at the entrance pupil of your eye), aberrations (except for distortion) are reduced. Further, while stopping down a lens does not alter the field of view, the throughput does get reduced.

However, this would be a terrible idea for a microscope. Why? Because unlike the eyeball which has a magnification much less than 1, microscopes have magnifications much greater than 1. Stopping down a microscope objective (like any lens) increases both the depth of field and blur circle diameter, neither of which are desirable.

Confocal microscopy doesn't put a pinhole at the entrance (or exit) pupil of the lens, but rather a plane confocal to the object (hence the term 'confocal'). That is, a pinhole is imaged onto the sample. This is the origin of improved performance as compared to a widefield technique. To be sure, confocal microscopy can be performed with many pinholes (Nipkow disk) to increase image acquisition rates.

Now- pinhole cameras (camera obscura). The pinhole is located at the entrance pupil, and indeed, camera obscuras have very low levels of aberrations, large fields of view, and miniscule levels of throughput.

How about using a pinhole on a telescope? Indeed, they are used as part of a Hartmann-Shack wavefront sensor, a common component of adaptive optical systems. Otherwise, since you are manufacturing the telescope optics to be well-corrected in the first place, using a pinhole will only decrease your throughput.

Hope this helps.