I'm trying to grasp an understanding of just what a collimator lens does in comparison to a condenser?
Can anyone enlighten me in regard to the 'collection' of light in both cases and basically where it goes from there?
To put it another way, what is the difference between a condenser and a collimating lens?
Craig
Collimator/ Condenser
Moderators: rjlittlefield, ChrisR, Chris S., Pau
-
augusthouse
- Posts: 1195
- Joined: Sat Sep 16, 2006 1:39 am
- Location: New South Wales Australia
-
augusthouse
- Posts: 1195
- Joined: Sat Sep 16, 2006 1:39 am
- Location: New South Wales Australia
To be more specific, I'm trying to predict what the item below will do. I don't have the actual item to trial - just the pics.
It came from a machine that had a fiber optic cable snapped into the holder at the output of the assembly.
Craig
It came from a machine that had a fiber optic cable snapped into the holder at the output of the assembly.
Craig
Last edited by augusthouse on Tue Dec 11, 2007 4:36 pm, edited 1 time in total.
-
augusthouse
- Posts: 1195
- Joined: Sat Sep 16, 2006 1:39 am
- Location: New South Wales Australia
One definition that I have come across.
"Collimation could mean different things in different areas of science.
In optics, collimation means making a diverging (expanding) or converging (concentrating) beam of light (or other particles) into a parallel beam.
A parallel beam of light is one whose size (seen, for example, by
projecting it onto a wall) does not change as you move the light source
closer or further from the wall."
Here is a diagram from a different source. It's the area to the left of the 'pinhole' that interests me.
My initial intention is to use a flash unit SB-28 as the light source (eventually just a flash tube - see Charlie's article) and a fiber optic cable as the destination.
Craig
"Collimation could mean different things in different areas of science.
In optics, collimation means making a diverging (expanding) or converging (concentrating) beam of light (or other particles) into a parallel beam.
A parallel beam of light is one whose size (seen, for example, by
projecting it onto a wall) does not change as you move the light source
closer or further from the wall."
Here is a diagram from a different source. It's the area to the left of the 'pinhole' that interests me.
My initial intention is to use a flash unit SB-28 as the light source (eventually just a flash tube - see Charlie's article) and a fiber optic cable as the destination.
Craig
-
rjlittlefield
- Site Admin
- Posts: 23621
- Joined: Tue Aug 01, 2006 8:34 am
- Location: Richland, Washington State, USA
- Contact:
Craig,
Your definition of "collimation" is correct -- a collimator's job is to convert a converging or diverging beam of light into a parallel beam.
A condenser's job is normally to convert a diverging beam into a converging beam, in order to get the light from where it is, to where it needs to be.
For example in the case of a slide projector, the condenser lenses take diverging light from the bulb and bend it so that it passes through the slide and then converges on the aperture of the projection lens. Without the condenser, the corners of the slide would be dark because light passing from the lamp filament through the corners of the slide would keep diverging and miss the projection lens completely.
There is a similar situation in coupling light from a bulb into an optical fiber. Without some sort of focusing, most of the light will never hit the end of the optical fiber and will just be wasted. To keep that from happening, a combination of mirrors and lenses is used to focus or "condense" the light into a small region that is roughly the same size as the end of the fiber bundle.
I am not familiar with the exact device in your photos. But the lenses inside the blue fluted cylinder look very much like aspheric condensers, probably to do what I just described.
BTW, the condenser in a microscope is really designed to do two jobs. First is to concentrate light where it is needed, on a small diameter disk where the specimen sits. But more important, the microscope condenser also serves to make the beam very strongly converging below the subject, so that it will be strongly diverging above the subject. This allows the entire aperture of the objective lens to come into play, which significantly increases the resolution beyond what you would get with a parallel or only slightly diverging beam. See http://www.photomacrography.net/forum/v ... php?t=3869 for an illustration of what a microscope condenser does.
--Rik
Your definition of "collimation" is correct -- a collimator's job is to convert a converging or diverging beam of light into a parallel beam.
A condenser's job is normally to convert a diverging beam into a converging beam, in order to get the light from where it is, to where it needs to be.
For example in the case of a slide projector, the condenser lenses take diverging light from the bulb and bend it so that it passes through the slide and then converges on the aperture of the projection lens. Without the condenser, the corners of the slide would be dark because light passing from the lamp filament through the corners of the slide would keep diverging and miss the projection lens completely.
There is a similar situation in coupling light from a bulb into an optical fiber. Without some sort of focusing, most of the light will never hit the end of the optical fiber and will just be wasted. To keep that from happening, a combination of mirrors and lenses is used to focus or "condense" the light into a small region that is roughly the same size as the end of the fiber bundle.
I am not familiar with the exact device in your photos. But the lenses inside the blue fluted cylinder look very much like aspheric condensers, probably to do what I just described.
BTW, the condenser in a microscope is really designed to do two jobs. First is to concentrate light where it is needed, on a small diameter disk where the specimen sits. But more important, the microscope condenser also serves to make the beam very strongly converging below the subject, so that it will be strongly diverging above the subject. This allows the entire aperture of the objective lens to come into play, which significantly increases the resolution beyond what you would get with a parallel or only slightly diverging beam. See http://www.photomacrography.net/forum/v ... php?t=3869 for an illustration of what a microscope condenser does.
--Rik
-
augusthouse
- Posts: 1195
- Joined: Sat Sep 16, 2006 1:39 am
- Location: New South Wales Australia
Thanks for that Rik. Appreciated!
Yesterday I read your linked post 'Visualizing the effect of a microscope's condenser aperture' that you mentioned just after you uploaded it.
I found your post fascinating! I was especially intrigued by the 'oblique' shot in your second post for reasons apart from the documentation perspective. It's like viewing lightning above the clouds from space.
Thanks also for the examples above regarding the projector and microscope condenser. I can see the pattern now and the role each component fulfills.
Craig
Yesterday I read your linked post 'Visualizing the effect of a microscope's condenser aperture' that you mentioned just after you uploaded it.
I found your post fascinating! I was especially intrigued by the 'oblique' shot in your second post for reasons apart from the documentation perspective. It's like viewing lightning above the clouds from space.
Thanks also for the examples above regarding the projector and microscope condenser. I can see the pattern now and the role each component fulfills.
Craig
-
rjlittlefield
- Site Admin
- Posts: 23621
- Joined: Tue Aug 01, 2006 8:34 am
- Location: Richland, Washington State, USA
- Contact:
Glad I could help, Craig. It took me a long time to get clear about even the simplest condenser systems -- what they do and how they work. I still have to stop and think carefully about anything with more than one lens in it, and some of the microscope systems still look like magic.*
In the fiber illuminator that I use, all of the focusing (condensing) in the base assembly is done with a strongly curved mirror that is manufactured as part of the bulb assembly. There are no lenses between the bulb and the fiber. The mirror covers about 3/4 of the spherical area around the bulb and is so strongly curved that the filament focuses just a few inches in front of the bulb. This bulb, Philips EKE 21 V150W, appears to be made specifically for use in fiber illuminators and similar small-format, short-focus applications. If I swapped in a different bulb assembly, probably it wouldn't work as well.
In the pictures that you've posted, I can't read enough of the label to tell what kind of bulb that is.
But I guess the main point is that ideally, all of the parts coordinate to give high efficiency.
On the other hand, if you start off with lots more light than you really need, then the system can work fine even if a lot of light gets lost. If I understand his setup correctly (sixth post in your earlier topic), Graham Matthews gets great results from just positioning the input end of a fiber close to his camera flash, no other coupling at all. Sometimes simple is beautiful!
--Rik
* Any sufficiently advanced technology is indistinguishable from magic. Arthur C. Clarke, "Profiles of The Future", 1973 revision (ref).
In the fiber illuminator that I use, all of the focusing (condensing) in the base assembly is done with a strongly curved mirror that is manufactured as part of the bulb assembly. There are no lenses between the bulb and the fiber. The mirror covers about 3/4 of the spherical area around the bulb and is so strongly curved that the filament focuses just a few inches in front of the bulb. This bulb, Philips EKE 21 V150W, appears to be made specifically for use in fiber illuminators and similar small-format, short-focus applications. If I swapped in a different bulb assembly, probably it wouldn't work as well.
In the pictures that you've posted, I can't read enough of the label to tell what kind of bulb that is.
But I guess the main point is that ideally, all of the parts coordinate to give high efficiency.
On the other hand, if you start off with lots more light than you really need, then the system can work fine even if a lot of light gets lost. If I understand his setup correctly (sixth post in your earlier topic), Graham Matthews gets great results from just positioning the input end of a fiber close to his camera flash, no other coupling at all. Sometimes simple is beautiful!
--Rik
* Any sufficiently advanced technology is indistinguishable from magic. Arthur C. Clarke, "Profiles of The Future", 1973 revision (ref).
-
augusthouse
- Posts: 1195
- Joined: Sat Sep 16, 2006 1:39 am
- Location: New South Wales Australia
Just another question in regard to this topic.
What is going on in a microscope 'collector' lens? What is the role of a 'collector' lens?
I also found another picture of the 'blue' gizmo referred to earlier in the thread. The bulb is rated at 12 volts 2.92 amps, 35 watts and the FO light guide is a product called Lumiglo. I gather it is designed for 'displays' and lighting effects.
It's only a small picture; but it's sufficient to satisfy my curiosity.
It should be up to the intended purpose as I won't be sending any constant heat through it - just bursts of 'flash' and I will be using a sheathed triple light guide.
It doesn't matter if some light is wasted - the Nikon SB-28 has heaps of power and I am currently only using it in the range of 1/2, 1/4, 1/8 duration, but if I can expand this range and utilize the shorter durations (1/16, 1/32, 1/64th) it will provide more options with regard to lighting various subjects.
The other idea was to use a PALMBLAZE Luxeon® K2 White LED torch (6500K) for the modeling or 'viewing' light. I assume these torches are 'slim'. ( * later note: 7/8ths of an inch in diameter and 4 3/4" long)
The 'viewing' light in this case is just for composition and focusing, etc. This is all speculation; but worth exploring. It would sit beside the SB-28 on a rail that will allow me to move one or the other into place behind the 'collimating' lens as required (there is a simpler way of doing this without the rail, I'll take some pics of the box thingo I've made and upload them).
I'd like to see what happens when you put one of these torches on the end of a fiber optic cable?? The PALMBLAZE Luxeon® K2 White LED torch costs US$29.99.
Craig
What is going on in a microscope 'collector' lens? What is the role of a 'collector' lens?
I also found another picture of the 'blue' gizmo referred to earlier in the thread. The bulb is rated at 12 volts 2.92 amps, 35 watts and the FO light guide is a product called Lumiglo. I gather it is designed for 'displays' and lighting effects.
It's only a small picture; but it's sufficient to satisfy my curiosity.
It should be up to the intended purpose as I won't be sending any constant heat through it - just bursts of 'flash' and I will be using a sheathed triple light guide.
It doesn't matter if some light is wasted - the Nikon SB-28 has heaps of power and I am currently only using it in the range of 1/2, 1/4, 1/8 duration, but if I can expand this range and utilize the shorter durations (1/16, 1/32, 1/64th) it will provide more options with regard to lighting various subjects.
The other idea was to use a PALMBLAZE Luxeon® K2 White LED torch (6500K) for the modeling or 'viewing' light. I assume these torches are 'slim'. ( * later note: 7/8ths of an inch in diameter and 4 3/4" long)
The 'viewing' light in this case is just for composition and focusing, etc. This is all speculation; but worth exploring. It would sit beside the SB-28 on a rail that will allow me to move one or the other into place behind the 'collimating' lens as required (there is a simpler way of doing this without the rail, I'll take some pics of the box thingo I've made and upload them).
I'd like to see what happens when you put one of these torches on the end of a fiber optic cable?? The PALMBLAZE Luxeon® K2 White LED torch costs US$29.99.
Craig
-
rjlittlefield
- Site Admin
- Posts: 23621
- Joined: Tue Aug 01, 2006 8:34 am
- Location: Richland, Washington State, USA
- Contact:
Craig,
About the "collector lens"...
It's common for the illumination system of a microscope to consist of two big chunks. The first chunk (describing my own scope) might be a light bulb, a concave mirror (in back of the bulb), one lens (in front of the bulb), an iris diaphragm, and a plane mirror, the whole mess working in combination to produce a roughly parallel beam of light that shoots upward from the base. The second chunk then consists of more lenses and another iris diaphragm, this chunk working to form the beam into that cone with a wide adjustable angle and a narrow neck that you need to get a bright high resolution image.
The "collector lens" is that one in the base, closest to the lamp, that forms the light into a roughly parallel beam. (So, that lens is also acting as a "collimator".)
See http://www.microscopyu.com/articles/opt ... nents.html .
This distinction between "condenser" and "collector lens" is partly physical, partly nomenclature. In microscopes, the collector lens and condenser are usually far apart and largely independent, and it makes sense to think and talk about them separately. In enlargers and projectors, there are lens elements that do similar jobs, but they are much closer together and are usually lumped under the term "condenser".
--Rik
About the "collector lens"...
It's common for the illumination system of a microscope to consist of two big chunks. The first chunk (describing my own scope) might be a light bulb, a concave mirror (in back of the bulb), one lens (in front of the bulb), an iris diaphragm, and a plane mirror, the whole mess working in combination to produce a roughly parallel beam of light that shoots upward from the base. The second chunk then consists of more lenses and another iris diaphragm, this chunk working to form the beam into that cone with a wide adjustable angle and a narrow neck that you need to get a bright high resolution image.
The "collector lens" is that one in the base, closest to the lamp, that forms the light into a roughly parallel beam. (So, that lens is also acting as a "collimator".)
See http://www.microscopyu.com/articles/opt ... nents.html .
This distinction between "condenser" and "collector lens" is partly physical, partly nomenclature. In microscopes, the collector lens and condenser are usually far apart and largely independent, and it makes sense to think and talk about them separately. In enlargers and projectors, there are lens elements that do similar jobs, but they are much closer together and are usually lumped under the term "condenser".
--Rik
-
augusthouse
- Posts: 1195
- Joined: Sat Sep 16, 2006 1:39 am
- Location: New South Wales Australia
The items referred to arrived in the mail the other day so I have uploaded a couple of images.
The light source is a PalmBlaze LED Luxeon K2 torch.
The 'collected light' converges into a beam approx. 10mm in diameter (as seen in the first picture). The second picture is the PalmBlaze doing its own thing. It has a square beam.
When the light source is moved further back from the 'lens' - say, from 35mm to 50mm, the diameter of the beam decreases and it's time to put on sunglasses!
Craig
The light source is a PalmBlaze LED Luxeon K2 torch.
The 'collected light' converges into a beam approx. 10mm in diameter (as seen in the first picture). The second picture is the PalmBlaze doing its own thing. It has a square beam.
When the light source is moved further back from the 'lens' - say, from 35mm to 50mm, the diameter of the beam decreases and it's time to put on sunglasses!
Craig
-
augusthouse
- Posts: 1195
- Joined: Sat Sep 16, 2006 1:39 am
- Location: New South Wales Australia
Gene,
Sorry about that. At the time they were just what I was looking for and I was rather determined. My 'proxy' had them well and truly covered.
The seller had about four of them in one of those multiple item auctions. I was going for two of them and picked them up at a decent price - when you take shipping costs into consideration.
Haven't really fine-tuned their placement yet. There are other ways of achieving the same outcome, but these little guys just looked the part.
Craig
Sorry about that. At the time they were just what I was looking for and I was rather determined. My 'proxy' had them well and truly covered.
The seller had about four of them in one of those multiple item auctions. I was going for two of them and picked them up at a decent price - when you take shipping costs into consideration.
Haven't really fine-tuned their placement yet. There are other ways of achieving the same outcome, but these little guys just looked the part.
Craig
To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!"
I didn't have them well and truly covered, just shot in a low ball snipe.
Hoping to get it cheep and figured it was nice enough to attract other optics guys.
The EKE is one of the standard bubbs for fiber optic illuminators. Somewhat interchangeable with the DDL and EJA and EJN and one or two others.
Variations in exact operating voltage, color temp delivered, focal spot distance and size, and rated hours. Looks like that gadget is more of a condensor than a collimator since it shrinks your flashlight beam.
Hoping to get it cheep and figured it was nice enough to attract other optics guys.
The EKE is one of the standard bubbs for fiber optic illuminators. Somewhat interchangeable with the DDL and EJA and EJN and one or two others.
Variations in exact operating voltage, color temp delivered, focal spot distance and size, and rated hours. Looks like that gadget is more of a condensor than a collimator since it shrinks your flashlight beam.
Will this perform the same function? I've created a fiber optic attachment for the built in flash on my camera and wondering if this could be used to increase the output.
http://cgi.ebay.com/High-Quality-Plasti ... dZViewItem
http://cgi.ebay.com/High-Quality-Plasti ... dZViewItem
-
augusthouse
- Posts: 1195
- Joined: Sat Sep 16, 2006 1:39 am
- Location: New South Wales Australia
That's a good question elf. Do you have an image of the attachment you have made?
I haven't tried to use this method with the onboard flash.
The collimating lens you have linked to is a small one used in laser optic setups.
I assume you have this attached directly to the FO light guide?
Speedlight approach reference link. http://www.visionarydigital.com/trilight.html
Craig
I haven't tried to use this method with the onboard flash.
The collimating lens you have linked to is a small one used in laser optic setups.
I assume you have this attached directly to the FO light guide?
Speedlight approach reference link. http://www.visionarydigital.com/trilight.html
Craig
To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!"
-
Charles Krebs
- Posts: 5865
- Joined: Tue Aug 01, 2006 8:02 pm
- Location: Issaquah, WA USA
- Contact:
Elf...
That looks too small (diameter) to "gather" any appreciable amount of light from your flash.
Craig...
What was the eBay item # for the piece you showed. It seems like this should be an item that is not too hard to find from a f/o lighting supplier but I looked around for something like that about a year ago and couldn't find it. Are there any manufacturers names or designations on it?
That looks too small (diameter) to "gather" any appreciable amount of light from your flash.
Craig...
What was the eBay item # for the piece you showed. It seems like this should be an item that is not too hard to find from a f/o lighting supplier but I looked around for something like that about a year ago and couldn't find it. Are there any manufacturers names or designations on it?