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Integrating a Mitutoyo tube lens in a macro rig
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Chris S.
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PostPosted: Mon Feb 07, 2011 12:30 pm    Post subject: Integrating a Mitutoyo tube lens in a macro rig Reply with quote

As Oskar suggested, maybe we should continue the discussion started here--about Mitutoyo tube lenses, and how to mount them in a macro rig--in its own thread. We've drifted pretty far from David's excellent comparison of lenses at 5x.

Horstl wrote:
If there is interest, I can test the MT40 also on a 24x36mm camera - this will not work together, but it would be possible to determine the usable field. I think APS should be acceptable.

Horst, welcome to the forum! Thanks for your information and photos, which are helpful. I'd be very interested in your results as you test this lens, though not for the vignetting issue in particular. You are the first person in this forum, so far as I know, to acquire an actual Mitutoyo tube lens. I don't know if you have anything to compare it with, but many of us would like to know if it offers any optical improvement over using a good camera lens.

The reason I'm not especially interested in where it vignettes is that the MT-40 is not the Mitutoyo tube lens I would choose if I purchased one. It is supplied in a mount that makes it easy for "enduser integration," as Mitutoyo calls it. I don't know if it this lens optically the same as the much cheaper MT-1--which requires an additional mount, but as Enrico pointed out, has a larger image circle. The required mount is readily available from Edmund, looks easy to install, and does not add enough cost to bring it up to the price of the MT-40.

Here is the list of parts I was considering (I'm currently looking in other directions, but might come back to it). All parts listed below are from Edmund Optics, unless specifically noted otherwise. It incorporates some good suggestions made by Charlie Krebs, and information obtained from Edmund Optics via email and phone. For example, there were some things I couldn't quite grasp without dimensional drawings not available online.

A.) MT-1 tube lens: $628 (Stock number NT54-774) As Enrico said, this is the 200mm tube lens with the larger stated imaged circle. (There is also the MT-2, which is 400mm, effectively doubling the objective's magnificiation. Pity there is no 100mm version--which would permit objectives to be used at half their rated magnification and--perhaps--higher resolution than objectives intended for the reduced magnification.)

B.) MT-1/MT-2 C-mount adapter: $159 (Stock number NT58-329) This is a two-part adapter designed specifically for the MT-1 or MT-2 tube lenses—no custom parts required. The adapter clamps around the tube lens and provides standard C-mount threads on both sides.

C.) Mitutoyo to C-mount 10mm adapter: $33 (Stock number NT55-743) This allows the objective to be nicely mounted on the tube lens.

D.) Male T-Mount to Female C-mount adapter: $39 (Stock number NT58-753) This is for the camera side of the tube lens—bumps the thread size up to T-mount to permit a wider tube to avoid vignetting.

E.) T-Mount Extension tube 100mm: $33 (Stock Number NT52-296)

F.) 35-60mm T-mount Fine Focus Tube: $71.00 (Stock number NT52-300)

G.) T-mount to Nikon F-mount adapter:free to me, because I have several, but very cheap online. Not an Edmund part.

E, F, and G fill the distance between the tube lens and the sensor on my Nikon D200. Others would want the correct adapter for their camera mount—most of which should be easily available off of a T-mount. And you would want to adjust for your camera’s “register” (also called flange focal distance)—the distance between the lens mount and the sensor. For Nikons, it is 46.5mm.


For solid mechanical support, I’d add the following:

H.) Arca-Swiss plate from Chris Hejnar (not an Edmund part) Chris Hejnar makes some extra-thick Arca-Swiss style plates—iirc, ¾ or 1-inch thick. Probably overkill--and he also makes plates of normal thickness. In any event, I’d want everything mounted solidly on an Arca-Swiss plate of some kind.

I.) T-Mount 48mm Ring Mount with ¼-20 tapped hole: $65 (Stock number NT52-304) I’d probably get two of these. They would clamp around the T-Mount tubes and provide a thread for bolting them onto the Arca-Swiss plate.

J.) C-Mount 30mm Ring mount with ¼-20 tapped hole: $65 (Stock number NT52-930) Perhaps optional, but I'd like solid support on both sides of the tube lens. This would clamp around the C-adapter on the objective-end of the assemblage (might need to add a bit of C-tube to get room for the clamp) and provide a means of bolting it firmly to the Arca-Swiss plate. Due the difference in the size of parts "I" and "J," There would need to be some vertical support between the Arca-Swiss plate and this ring. I'd probably just start with a bolt, a nut, and a few washers, and then make something a bit better once I saw how this worked.

K.) Optional: Mitutoyo Filter Holder $69 (Stock number NT56-993)
This would be good for placing a polarizer (analyzer) in the light path. Alternatively, the polarizer could be placed in a simple C-tube, with retaining rings.

Additional thoughts: As experimentation with tube lenses continues, I'm leaning toward the use of a focusing helicoid rather than the fine focus tube listed above. My original thought was that focusing the tube lens would be done rarely and precisely. Now it appears that there may be good reasons to rack the tube lens farther from the sensor than 200mm, and that speed of such adjustment, rather than absolute precision, is more important. After just a quick look, it appears that most of the focusing helicoids are for M42, rather then T-mount. (These are both 42-mm, but have different thread pitches.) So some changes might be in order if that direction is undertaken.

Also, while the above approach would likely provide both mechanical and optical quality (at a price), it would not offer the ability to quickly change to tube lenses of different focal lengths. I'm increasingly seeing this capability as being very important.

Cheers,

--Chris

Edited to correct mistake pointed out by Oskar (and various typos as I stumble across them).
Edited again 2-26-2010 to correct mis-typed Nikon register from 46mm (incorrect) to 46.5mm (correct).


Last edited by Chris S. on Sat Feb 26, 2011 1:47 am; edited 3 times in total
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ChrisLilley



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PostPosted: Mon Feb 07, 2011 2:37 pm    Post subject: Reply with quote

Chris, good idea to start a new thread.

On first look, the C-mount seems to be the vignetting bottleneck in this setup. Unless the Mitutoyo tube lens is much smaller than that so is itself the bottleneck.

I like the idea of building an AS plate into this.
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Oskar O



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PostPosted: Mon Feb 07, 2011 3:30 pm    Post subject: Reply with quote

Sounds like a good plan. Maybe would be good to sketch a little on how to attach the whole thing? On a quick read, the C-tube thread mount may be a bit excessive, of course depending on how easily it can be fastened. But I think a sturdy rail with several attachment points is the right way to go, attaching from one point only doesn't really work that well. I'm not sure you need an especially thick rail, a solid aluminum rail should be enough at these lengths and weights.

BTW, some of those Edmund codes are worth double checking, at least the 100 mm T-mount extension seems to be NT52-296.

About helicoids, Schneider makes some pretty nice helicoids for industrial use. They have no play, allow reasonably fine adjustment and are lockable in position, something which might benefit your application. I have a Unifoc 58 myself, comes with a M39 mount for lenses -- it's at a whole different quality level than the Chinese M42 tubes on eBay. On a whole different price level too, but I got a good deal on a 2nd hand one on eBay. I suggest you check those out unless you know of some really nice helicoid model that I've never heard about Smile
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typestar



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PostPosted: Mon Feb 07, 2011 5:13 pm    Post subject: Re: Integrating a Mitutoyo tube lens in a macro rig Reply with quote

Chris S. wrote:
The reason I'm not especially interested in where it vignettes is that the MT-40 is not the Mitutoyo tube lens I would choose if I purchased one. It is supplied in a mount that makes it easy for "enduser integration," as Mitutoyo calls it. I don't know if it this lens optically the same as the much cheaper MT-1--which requires an additional mount, but as Enrico pointed out, has a larger image circle. The required mount is readily available from Edmund, looks easy to install, and does not add enough cost to bring it up to the price of the MT-40. ...
Also, while the above approach would likely provide both mechanical and optical quality (at a price), it would not offer the ability to quickly change to tube lenses of different focal lengths. I'm increasingly seeing this capability as being very important.
--Chris


@Chris, Horst and all you professionals here...

I am glad to read here, that (more than one year after I stumbled over the Mitutoyo lenses and their quality late 2009) - a vivid discussion about the use and quality of this highend lenses is going on here...
I have let produce fitting adapters (black anotized aluminium, perfect made) but unfortunately do not have a stable rig for testing all..., and did not find the time to test all of it, unfortunately)

There is -- I do not know why - some confusion caused by the different article-numbers that are given from Edmund optics.

I ordered my MT-4 Mitutuyo tube lens in january 2010 from Edmund optics. It is still available:
http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=2230&PageNum=1&StartRow=1

As I checked last days, for some days now on the Edmund-Optics website 2 (!) MT-40 lenses had been listedwith exactly same "MT-40" part-names, but different field of view and price (one cheaper with 30mm field of view, one more expensive with 24 mm field of view)
This has been corrected now again... -- there are now - as last year -
the MT-4 and an MT-40

"my" MT-4 tube lens (Article number NT54-428) should - as described on the web-site - provide an field of view of 30 mm and is cheaper than the MT-40. Last year, in january 2010 you could only order the MT-1, MT-2, MT-4 MT-L and MT-L4 tube lenses...

So, for all of you that are interested, the MT-4 is still available (not to be mixed up with the MT-40 - which seems to have a smaller image-circle...
If anyone here is interested in very well made direct-adapters for the MT-4 lens (as a tube for direct fitting into Nikon or T-2) I could show you my manufactured anotized adapters, only at the end of this week, because I am not at home now...

Dear Horst, please keep us updated with your tests (und schön, dass hier auch ein paar Österreicher sind - nice to have some Austrians here...)

Best pictures for all of you with this and other lenses...!

christian


Last edited by typestar on Tue Feb 08, 2011 2:21 am; edited 2 times in total
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Chris S.
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PostPosted: Mon Feb 07, 2011 5:40 pm    Post subject: Reply with quote

Chris, from the dimensional drawing I have (mechanical, not optical, and with some key dimensions not marked, though calculable if the drawings are to scale), I can't be sure. My sense is that the C-mount might block a bit of the glass at the edge, but likely only a very small bit. My guess is that the vignetting point would be gated by the image circle the tube lens is designed to cast, rather than its diameter--but I'm far from knowledgeable on these matters.

Oskar, thanks for catching my error--I've gone back and corrected it in the initial post. If anyone sees other errors, please likewise point them out.

I'll definitely look into those Scheider helicoids. I have, in fact, just started looking at various helicoids, and don't come close to knowing all (or even many) of them. I was wondering about those eBay ones--suspected they weren't all that great. Thanks for the tip!

Yes, a sketch would be a good idea, but is probably beyond my very poor drawing skills. A CAD drawing would be great, but see above comment. And as I mentioned earlier, I'm currently looking in other directions--will want a helicoid mount, but may very well not use the Mitutoyo tube lens. Will almost certainly put anything on an AS plate. I'm sure you're right--an extra thick rail is almost surely not needed; but if Chris Hejnar has one at little extra cost, I might go for a bit of overkill, if only to make something that is really easy to handle.

Agreed that in this scenario, the support for the C-mount end is probably overkill. But if I add a filter holder (for polarization) or beam splitter (for through-the-lens illumination, I might be cantilevering the objective further out into space, at which point a bit of support at that end might be nice. I try to build with a little future-proofing included.

Christian, perhaps the rest of us are finally catching up with you. Smile

According to the Edmund literature, the MT-4 and MT-40 tube lenses have different purposes; the MT4 is recommended for use with objectives under 20x; the MT-40 for objectives 20x and above. Why or how, I have no idea; but no similar split use is recommended for the MT-1. So are the MT-4/MT-40 lenses different optically from the MT-1, or just mechanically? I have no idea. But since I currently have 10x, 20x, and 50x Mitutoyo apo objectives (and may add others), and want to use the same tube lens for all, I would likely prefer the MT-1, in the absence of better information.

Cheers, all!

--Chris
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Chris S.
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PostPosted: Mon Feb 07, 2011 8:05 pm    Post subject: Reply with quote

Here is a diagram of the MT-1/MT-2 C-mount adapter (item "B" on my list at the top of this thread). While Edmund has many such diagrams available at their Website, I couldn't find one for this particular item. A customer support engineer at Edmund was kind enough to send this to me in January, 2011. I doubt there is any problem with sharing it, but we might want to remember, as this thread ages, that items and specifications change--so one might wish to confirm the information is current before relying on it. (Note that I didn't crop the bottom off, but received that way--though there seems to be nothing of value lost.)




Here is another drawing sent to me by Edmund, which is similar to one available online, but contains a bit of extra information. The blue portions represent a top and side view of the MT-1 tube lens (item "A" on the list at top), as it would be arranged in use.

A similar drawing, plus such drawings for some of the other tube lenses, can be found on page 23 of the pdf available here.

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Horstl



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PostPosted: Tue Feb 08, 2011 6:28 am    Post subject: Re: Integrating a Mitutoyo tube lens in a macro rig Reply with quote

Chris S. wrote:

... I don't know if you have anything to compare it with, but many of us would like to know if it offers any optical improvement over using a good camera lens....


Hello Chris,

I have not compared it with other lenses yet.
What I have seen so far from David's (and others) well done tests, I think there is not much room for improvement - it is already terrific.
One of the reasons that I choose the original lens some time ago, was, that I didn't want to risk any disappointment anymore. I gave up this beautiful hobby for years due to (for photographic purposes) inadequate optics (no Plan Apo's). Fortunately we needed a system for high quality documentation purposes at my working place where cost was not the limiting factor. The Mitutoyo system looked very promising and so we tried it. This was a good decision, it is so much fun to use this high-quality stuff that I came back to this as a hobby too.

But first - as Christian mentioned - there is some confusion going on with the tube lenses. Shocked
I `m not sure anymore if I ordered a MT-4 or a MT-40 lens, I think there was only one type available at that time. Now there are two MT-40 lenses with different part numbers listed at Edmund:




The technical documentation at Edmunds still shows a "MT-4" lens:



This is also contrary to Mitutoyo's original documentation, there is only one MT-40 and no MT-4 described:







"Bildfeld" means "image circle", -24 mm for the MT-40.

So there are the standard tube lenses MT-1/MT-2/MT-40 and the "L" types, for a wider wavelength range.
Maybe Mitutoyo recently introduced a MT-40 lens with extended wavelength range and this lens is not yet documented in their pdf's - this should then be named correctly MT-L-40 and would explain the big price difference to the standard MT-40. Just a guess. The other explanation is, that nobody should listen the full live version of "dazed and confused" during writing technical documentations and boring parts-lists.

@ Christian: Griaß' Di aus Tirol!
Mabe you could show us a picture of your MT-40/MT-4 whatever, so we can compare them and clarify this circumstance.

Horst
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Oskar O



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PostPosted: Tue Feb 08, 2011 10:48 am    Post subject: Reply with quote

Chris S. wrote:

I'll definitely look into those Scheider helicoids. I have, in fact, just started looking at various helicoids, and don't come close to knowing all (or even many) of them. I was wondering about those eBay ones--suspected they weren't all that great. Thanks for the tip!


You're welcome. I don't think the commonly sold M42 helicoids on eBay are bad (OK, I haven't tried everyone, but they all look alike), just that I wouldn't use them at the magnifications your system ends up using. At high magnification, life is a lot easier without any play in the tubes Smile

I'm still working on my setup, but I kind of like the locking screw on my Schneider unifoc -- it helps to prevent slight shifts by accident and if I ever end up doing a vertical setup, it should eliminate all creep. Please let us know if you find other interesting helicoids. I guess the real challenge will be to keep quality up while keeping the price down...

Chris S. wrote:

Agreed that in this scenario, the support for the C-mount end is probably overkill. But if I add a filter holder (for polarization) or beam splitter (for through-the-lens illumination, I might be cantilevering the objective further out into space, at which point a bit of support at that end might be nice. I try to build with a little future-proofing included.


Of course supporting at the ends is best. I was mainly thinking about the space for a C-mount support. I've been thinking about the same problems, but I'm not looking at using a Mitutoyo or Nikon tube lens so my solutions will be slightly different. If the tubing is rigid enough, then two points of support, both at the ends, should be good, but that will be seen.

Another interesting situation comes when starting to consider how to quickly change the tube lens to change the magnification. I don't know if that was part of your plan, but I think it's a potentially interesting problem since it would enable to cover the "intermediate" magnifications without cropping.
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Chris S.
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PostPosted: Tue Feb 08, 2011 10:30 pm    Post subject: Reply with quote

Horst,

Aha! Brilliant that you thought to upload a screen shot of the Austrian version of the Edmund Optics Website. A comparison with the American version of the site clears up a bit of mystery. Check out the screen shot of the American version below--the stock numbers and specifications for "MT-40" listed near the top of your Edmund site match the ones for our "MT-4."



Further, the paper Edmund catalog I have on my desk is clear about identifying both these lenses, and states that the MT-4 is for objectives below 20x, the MT-40 for objectives 20x and above.

My guess is that somebody erroneously added an extra zero to "MT-4" on the site for your market.


Oskar O wrote:
I'm still working on my setup, but I kind of like the locking screw on my Schneider unifoc -- it helps to prevent slight shifts by accident and if I ever end up doing a vertical setup, it should eliminate all creep. Please let us know if you find other interesting helicoids. I guess the real challenge will be to keep quality up while keeping the price down....

You said it, Oskar! I looked at those Scheider helicoids last night. Great stuff, they seem--but the prices, oof. And apparently not an item that often comes up on eBay.

Oskar O wrote:
I was mainly thinking about the space for a C-mount support.

I agree it might be an issue, but it would be pretty easy to add a short C-mount tube in there to procide something to clamp around, as this particular dimension can be safely varied within wide parameters. I should probably have added a short C-tube to the parts list in the first post.

Oskar O wrote:
I've been thinking about the same problems, but I'm not looking at using a Mitutoyo or Nikon tube lens so my solutions will be slightly different. If the tubing is rigid enough, then two points of support, both at the ends, should be good, but that will be seen.

Another interesting situation comes when starting to consider how to quickly change the tube lens to change the magnification. I don't know if that was part of your plan, but I think it's a potentially interesting problem since it would enable to cover the "intermediate" magnifications without cropping.

This is one of the big reasons I put aside the approach I described in this thread. I spent some hours pouring over the Edmund Website and catalog, and corresponding with Edmund engineers, and initially balked when I saw the total cost of my shopping cart. Then I tried a stack using my Mitutoyo 10x apo with my Nikkor 105 f/2.8 AF-D micro lens for decollimation. The results were really great--very close to those of my Nikon CFN 4x/0.20 apo finite, which is an incredible optic. So I decided that if at all possible, I wanted to make it easy to change the focal length of the decollimating lens. That's why I mentioned I was currently looking in other directions. I posted this because the subject was under discussion, and I thought maybe my homework might be useful to somebody.

Cheers,

--Chris
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SONYNUT



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PostPosted: Tue Feb 08, 2011 11:30 pm    Post subject: Reply with quote

don't know if anyone posted this place yet...probably...but here it is again..


http://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1749
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Horstl



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PostPosted: Wed Feb 09, 2011 1:56 am    Post subject: Reply with quote

Chris S. wrote:
....
Further, the paper Edmund catalog I have on my desk is clear about identifying both these lenses, and states that the MT-4 is for objectives below 20x, the MT-40 for objectives 20x and above....


Hello Chris,

thank you for this useful information, I´m pretty sure now, that I have the lens with the part nr. NT54-428 (MT-4).
I´m still wondering about the price difference to the MT-40, because I think the only difference could be the entrance pupil dimension, which might be different to better match the larger magnification objectives (?)

However, you brought me to some completely new considerations.
I also have a set of high magnification MPlan Apo's, the 100x, 50xSL, and the 20x. They are difficult to use, a very stable and precise platform is needed, otherwise it is a pain.
Hmm, but why not building one? Rolling Eyes
I have some rough ideas at the moment, involving the MT-1 tube lens, but need some time to think about the details.

Horst
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Oskar O



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PostPosted: Wed Feb 09, 2011 9:49 am    Post subject: Reply with quote

Chris S. wrote:

You said it, Oskar! I looked at those Scheider helicoids last night. Great stuff, they seem--but the prices, oof. And apparently not an item that often comes up on eBay.


Yes, expensive like the rest of the Schneider stuff Smile

One option is also to create a helicoid out of an old lens, but that has problems too, no easy solutions around. Might also be worth considering a smallish eBay helicoid and be prepared to make modifications to it if it isn't good enough.

Chris S. wrote:

This is one of the big reasons I put aside the approach I described in this thread. I spent some hours pouring over the Edmund Website and catalog, and corresponding with Edmund engineers, and initially balked when I saw the total cost of my shopping cart. Then I tried a stack using my Mitutoyo 10x apo with my Nikkor 105 f/2.8 AF-D micro lens for decollimation. The results were really great--very close to those of my Nikon CFN 4x/0.20 apo finite, which is an incredible optic. So I decided that if at all possible, I wanted to make it easy to change the focal length of the decollimating lens. That's why I mentioned I was currently looking in other directions. I posted this because the subject was under discussion, and I thought maybe my homework might be useful to somebody.


Well, it has been useful at least for me Smile
A zoom lens would be ideal, but that's even more complicated than tubes and helicoids. I don't think there's an ideal solution, but as you say, the results make it worth pursuing a flexible setup.
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Craig Gerard



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PostPosted: Fri Feb 11, 2011 1:25 am    Post subject: Reply with quote

This seems like an appropriate place to ask this question. It has been raised before, but I can't find the thread.

The Mitutoyo QV objectives are designated f=100, is there a Mitutoyo 100mm tube lense out there?

We know Mitutoyo have a 200mm, a 400mm but what tube lense did they intend for use with the QV objectives?

I presume QV stands for 'Quick Vision':
Quote:
Mitutoyo Quick Vision (QV) Measuring Machine from Mitutoyo America Corporation (Aurora, IL).


http://www.mitutoyo.com/pdf/1785VisionMeasrSys.pdf


Craig
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Blame



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PostPosted: Fri Feb 11, 2011 3:08 am    Post subject: Reply with quote

Craig

The QVs were never intended for use outside some very expensive mitutoyo industrial equipment. I asked and that is what they told me. Hence no 100mm tube lens. In fact the man was most adamant that the QVs were ONLY usable in there equipment.

Don't be fooled by the f=100. A QV "2.5x 0.14NA f=100" is just a standard "5x 0.14NA f=200" with a lens-less fitting adapter.

However the lack of a 100mm tube lens in the line up just about kills the whole deal for us. The mitutoyos work happily at less than 200mm even with a full frame camera. With a cropped frame 100mm would be a good choice.

It is a lot of money for a setup that just can't compete with morfa's 9$ 172mm lens from surplus shed or a 105mm macro.
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Horstl



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PostPosted: Fri Feb 11, 2011 6:47 am    Post subject: Reply with quote

Blame wrote:

...However the lack of a 100mm tube lens in the line up just about kills the whole deal for us. The mitutoyos work happily at less than 200mm even with a full frame camera. With a cropped frame 100mm would be a good choice.
...


I can understand this wish, but "working happily" is not a well defined limit for errors in an optical system.

The M Plan Apos in the range from 2x to 10x have the same ratio between magnification and n.A., giving constant f/18.
They should be (nearly) diffraction limited in their FOV (hopefully).
The resulting resolution specified by Mitutoyo is:
2x/0,055: 5µm
5x/014: 2µm
10x/0,28: 1µm

Multiplying the resolution with the magnification factor gives a constant value of 10µm in the sensor plane (thats one fine thing with this lenses).
To collect all this information the sensor should have a pixel size of approx. 5µm (this is for a b/w or "perfect" RGB-sensor, Sensors with the common Bayer Filter matrix should have a slightly higher resolution, hence modern DSLR's with pixel sizes between 4 and 5µm are already a perfect choice).
This oversampling will result in slightly blurred images at the 100% viewing level, but otherwise information is lost.

Now, when you change the focal length of the image formation lens, you are also changing the whole set of parameters.
With the implementation of a 100mm lens the magnification will be reduced to half of the specified value.
It is clear that the wish behind this is to get more field.
But now you (should, if everything is perfect) have a resolution of 5µm in the image plane, because the picture is smaller. Diffraction is going down due to a change of the effective focal ratio to f/9.
To adequate capture this image a sensor with 2-2,5µm pixels is required. Changing to larger pixels would be two steps in the false direction.
A 24x36 mm Sensor with 2µm pixels has a total of approx. 200 Mpix.
This would be the right tool to justify if this setup is working or not.

Horst
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