Thorlabs ITL200 adapters help needed

[nielsgeode]

I'm looking into purchasing adapters to get my ITL200 working in my setup and I'm following closeupphotography.net

Ideal is a 245mm sensor distance, so when using a Canon dslr (or a Sony mirrorless with adapter to Canon EF) this leaves an ITL200 thread - sensor distance of 201mm (245 - 44mm flang distance). Does it really make a difference to get this distance exactly right or is it not affecting image quality if the distance is a few milimeters shorter or longer? Thorlabs has stackable extension tubes that add 8.4 - 13.5 - 26.2 - 38.9 - 51.6 - 77.0 and 152.4 mm. With these distances it's (nearly) impossible to get it exact. Also, the adapter from EF mount to 52mm is also some millimeters thick and it's not entirely clear to me where exactly inside the SM2A20 adapter the ITL200 is positioned.

In the 52mm thread setup is a variable extension tube used (although together with the LSA). Does it make sense to add this adapter between sensor and ITL200? Or would something else work better or just as good?

Before ordering I'd like to make sure I get it right the first time so any help is appreciated

[Macro_Cosmos]

Ideal is a 245mm sensor distance, so when using a Canon dslr (or a Sony mirrorless with adapter to Canon EF) this leaves an ITL200 thread - sensor distance of 201mm (245 - 44mm flang distance). Does it really make a difference to get this distance exactly right or is it not affecting image quality if the distance is a few milimeters shorter or longer?

For the reversed setup, getting the distances right is absolutely crucial. I won't call it ideal myself (test coming).
The distances affect your magnification.
For Thorlabs' recommended mounting, just focus the TL to infinity, trivial, point at a distant tree and use a piece of cardboard as an aperture, increases contrast. This makes focusing easier.
For reversing, all distances matter. What are you going to use the TL for? If it's only 5x or 10x, then reversing is a bit better. Anything above 10x, reversing it gives worse results.

Thorlabs has stackable extension tubes that add 8.4 - 13.5 - 26.2 - 38.9 - 51.6 - 77.0 and 152.4 mm. With these distances it's (nearly) impossible to get it exact. Also, the adapter from EF mount to 52mm is also some millimeters thick and it's not entirely clear to me where exactly inside the SM2A20 adapter the ITL200 is positioned.

It is possible. Check out their variable tube.
https://www.thorlabs.com/newgrouppage9. ... up_id=3393
I recommend the slotted retainers and a spanner to secure the rings. It's a nuisance to work with but it works well.

That's why reversing is tricky, focusing it to infinity can't go wrong.

Likewise, the SM2A20 has M38x0.5 threads, you can buy a retaining ring.
https://www.thorlabs.com/thorproduct.cf ... ber=SM38RR
Yeah, $15 for this is overpriced.

In the 52mm thread setup is a variable extension tube used (although together with the LSA). Does it make sense to add this adapter between sensor and ITL200? Or would something else work better or just as good?

Add the variable tube behind the ITL200, buy yourself an SM2Mxx type tube with no external threading. Example: SM2M20

[rjlittlefield]

OK, now I am curious.

I set up my ITL200 today, in reversed configuration, focused it to infinity, and I measure about 245 mm from the lens threads to the sensor. (I can't tell exactly, because my setup has the ITL200 mounted inside an M42 tube.)

In the reversed arrangement that you're talking about, is the ITL200 not focused at infinity?

If it is not, that could certainly explain why it works OK with 5X and 10X objectives, but not higher.

--Rik

[nielsgeode]

I have an ITL200, but never used it. Rik, is your experience that the Raynox DCR150 is better than the ITL200 for Mitutoyo objectives higher than 5x?

[nielsgeode]

What are you going to use the TL for? If it's only 5x or 10x, then reversing is a bit better. Anything above 10x, reversing it gives worse results.

On the one hand, I like to use the best tube lens for each microscope objective that I own. On the other hand, I regularly switch magnification and I don't like to change all the optics and adapters all the time. I have an ITL200, a Raynox and an LSA. The lenses I own are:
Nikon Plan APO 4x NA 0.20
Mitutoyo 5x
Mitutoyo 7.5x
Mitutoyo 10x
Mitutoyo 20x
Mitutoyo 50x

[Macro_Cosmos]

OK, now I am curious.

I set up my ITL200 today, in reversed configuration, focused it to infinity, and I measure about 245 mm from the lens threads to the sensor. (I can't tell exactly, because my setup has the ITL200 mounted inside an M42 tube.)

In the reversed arrangement that you're talking about, is the ITL200 not focused at infinity?

If it is not, that could certainly explain why it works OK with 5X and 10X objectives, but not higher.

--Rik

I must have missed something then. I was under the impression that the ITL200 is not focused to infinity when reversed. I've reversed focused to infinity before but measured something different? Must have been an error on my end then. I'll fix some things before posting the results.

I'm guessing mine was not exactly focused at infinity. However if at infinity, 245mm is measured, then it's safe to assume that Robert did the same thing. I'll ask him! But yeah, the lower mag, the results were slightly better. If I reverse focus it to infinity, I can use my measurescope setup, any problems will immediately show... that's good news. (Time to redo the test!)

I have an ITL200, but never used it. Rik, is your experience that the Raynox DCR150 is better than the ITL200 for Mitutoyo objectives higher than 5x?

Corners, yeah it would be a bit better. ITL200 wins in everything else.

On the one hand, I like to use the best tube lens for each microscope objective that I own. On the other hand, I regularly switch magnification and I don't like to change all the optics and adapters all the time. I have an ITL200, a Raynox and an LSA. The lenses I own are:
Nikon Plan APO 4x NA 0.20
Mitutoyo 5x
Mitutoyo 7.5x
Mitutoyo 10x
Mitutoyo 20x
Mitutoyo 50x

Agree, I hate rearranging things. I've a stubborn donkey when it comes to these stuff, I want virtually zero tolerances and the optical axis fully aligned, it's sometimes hard.

In your case, you should get yourself the CMH-200. It's better than the ITL200, and it's a TTL200 clone, not ITL200. The TTL200 is designed for VIS light, has better coatings. The manufacturer verified this. They are the ones selling the TL on ebay, I was told a "story". Would have been nicer if they just admitted it.

Review here: https://macrocosmosblog.wordpress.com/2 ... vs-itl200/

You can have the ITL200 reversed, and the CMH-200 in normal orientation. CMH-200 is $180+$40 shipping, ebay.

That's quite a good collection you have there I must say. Store them well. For 20x and 50x, it's better to not reverse the ITL200.

[nielsgeode]

OK, now I am curious.

I set up my ITL200 today, in reversed configuration, focused it to infinity, and I measure about 245 mm from the lens threads to the sensor. (I can't tell exactly, because my setup has the ITL200 mounted inside an M42 tube.)

In the reversed arrangement that you're talking about, is the ITL200 not focused at infinity?

If it is not, that could certainly explain why it works OK with 5X and 10X objectives, but not higher.

--Rik

I must have missed something then. I was under the impression that the ITL200 is not focused to infinity when reversed. I've reversed focused to infinity before but measured something different? Must have been an error on my end then. I'll fix some things before posting the results.

I'm guessing mine was not exactly focused at infinity. However if at infinity, 245mm is measured, then it's safe to assume that Robert did the same thing. I'll ask him! But yeah, the lower mag, the results were slightly better. If I reverse focus it to infinity, I can use my measurescope setup, any problems will immediately show... that's good news. (Time to redo the test!)

I have an ITL200, but never used it. Rik, is your experience that the Raynox DCR150 is better than the ITL200 for Mitutoyo objectives higher than 5x?

Corners, yeah it would be a bit better. ITL200 wins in everything else.

On the one hand, I like to use the best tube lens for each microscope objective that I own. On the other hand, I regularly switch magnification and I don't like to change all the optics and adapters all the time. I have an ITL200, a Raynox and an LSA. The lenses I own are:
Nikon Plan APO 4x NA 0.20
Mitutoyo 5x
Mitutoyo 7.5x
Mitutoyo 10x
Mitutoyo 20x
Mitutoyo 50x

Agree, I hate rearranging things. I've a stubborn donkey when it comes to these stuff, I want virtually zero tolerances and the optical axis fully aligned, it's sometimes hard.

In your case, you should get yourself the CMH-200. It's better than the ITL200, and it's a TTL200 clone, not ITL200. The TTL200 is designed for VIS light, has better coatings. The manufacturer verified this. They are the ones selling the TL on ebay, I was told a "story". Would have been nicer if they just admitted it.

Review here: https://macrocosmosblog.wordpress.com/2 ... vs-itl200/

You can have the ITL200 reversed, and the CMH-200 in normal orientation. CMH-200 is $180+$40 shipping, ebay.

That's quite a good collection you have there I must say. Store them well. For 20x and 50x, it's better to not reverse the ITL200.

The CMH-200 only edges the ITL200 very slightly. Absolutely no difference should be expected in everyday shooting.

This suggests it does not make sense to get the CMH-200 if you already have an original ITL200.

When using the ITL200 in normal orientation with the Mitu 5x, how much worse is image quality compared to a reversed ITL200?

[Scarodactyl]

I think the idea is to have one in normal configuration and one reversed so you don't have to keep changing.
I have a cmh200 which I'm planning to use as a tube lens under a finite head (the tube lens built in to my olympus bh2-uma illuminator does nasty things to my mitutoyo objectives' corners) so I'm also curious about what the drawbacks to reverse mounting are for higher mags.

[rjlittlefield]

I must have missed something then. I was under the impression that the ITL200 is not focused to infinity when reversed. I've reversed focused to infinity before but measured something different? Must have been an error on my end then. I'll fix some things before posting the results.

I'm guessing mine was not exactly focused at infinity. However if at infinity, 245mm is measured, then it's safe to assume that Robert did the same thing. I'll ask him! But yeah, the lower mag, the results were slightly better. If I reverse focus it to infinity, I can use my measurescope setup, any problems will immediately show... that's good news. (Time to redo the test!)

If the magnification was different forward and reversed, then for sure at least one of the configurations was not focused at infinity. When the rear lens is focused at infinity, the magnification is exactly the ratio of focal lengths of the two lenses. A lens in air does not change its focal length when reversed, so the magnification won't change either.

Rik, is your experience that the Raynox DCR150 is better than the ITL200 for Mitutoyo objectives higher than 5x?

Essentially all I know about this issue is what's documented in the thread at https://www.photomacrography.net/forum/viewtopic.php?t=23898 .

In that series of tests, my DCR-150 significantly outperformed my copies of all the other tested lenses, at edges and corners of full frame, when configured as tested.

If that sounds cautious, it's because I'm very aware that results change with different configurations and other copies of the lenses.

I personally would rather spend my time doing things other than testing a zillion configurations to eke out the last bit of image quality. Further, I only recommend configurations that I'm sure can be reliably reproduced and will generalize to other objectives.

Combining those aspects, I stopped spending time on testing as soon as I found a "known good" solution that was easy to assemble using commonly available new equipment.

I now use Raynox DCR-150 as a go-to solution for all the infinity objectives I own, which go up to Mitutoyo 50X NA 0.55.

But I do not and never have made any claim that Raynox DCR-150 is the best possible. I fully expect that it is not, and I welcome careful and well documented tests showing better solutions.

--Rik

[Scarodactyl]

Ugh, all this "sensibility" and "actually spending your time taking photos instead of futzing with gear" is a real drag. I'm going to need you to get back on board with making the perfect the enemy of the almost-perfect.
(For most use cases I would think even the 12 dollar kenko #5 would be an excellent/sufficient option. I'll have to test mine to see how it compares to the cmh as an all-purpose tube lens, though that will need to be its own thread.)

[Macro_Cosmos]

This suggests it does not make sense to get the CMH-200 if you already have an original ITL200.

When using the ITL200 in normal orientation with the Mitu 5x, how much worse is image quality compared to a reversed ITL200?

Correct, however you said you want the best optimal setup for each, and you don't want to constantly change things.
Therefore, it makes sense to own two copies, right? One for low mag, the other for high mag.

I have to redo my test now. In the original, it's a big better reversed, at 5x. I don't have the Mit 5x, I use the one from Edmund Optics. It showed better results than the mit I used to own. The results can be generalised I believe.

[nielsgeode]

This suggests it does not make sense to get the CMH-200 if you already have an original ITL200.

When using the ITL200 in normal orientation with the Mitu 5x, how much worse is image quality compared to a reversed ITL200?

Correct, however you said you want the best optimal setup for each, and you don't want to constantly change things.
Therefore, it makes sense to own two copies, right? One for low mag, the other for high mag.

I have to redo my test now. In the original, it's a big better reversed, at 5x. I don't have the Mit 5x, I use the one from Edmund Optics. It showed better results than the mit I used to own. The results can be generalised I believe.

Is it correct that the exact ITL200 - mitutoyo distance is not important for sharpness as long as you're in the correct range?

How convenient are the SM2RC Ring Slip Clamps for frequent exchange of a system? In case you want to have 2 systems, how easy and quick is it to remove the tubes from the ring clamps compared to having 2 full sets, including 2 sets of clamps, one dedicated for each system?

Also I wonder if it is worth the extra cost to have 2 systems compared to one system in normal orientation? I already have 2 ITL200 lenses, but getting a full second set of clamps, plates and tubes is costing me several hundred euros extra. If the difference between normal and reversed orientation for 5x and 10x lenses is small I don't think it's worth the money to have 2 systems?

[Macro_Cosmos]

Is it correct that the exact ITL200 - mitutoyo distance is not important for sharpness as long as you're in the correct range?

How convenient are the SM2RC Ring Slip Clamps for frequent exchange of a system? In case you want to have 2 systems, how easy and quick is it to remove the tubes from the ring clamps compared to having 2 full sets, including 2 sets of clamps, one dedicated for each system?

Also I wonder if it is worth the extra cost to have 2 systems compared to one system in normal orientation? I already have 2 ITL200 lenses, but getting a full second set of clamps, plates and tubes is costing me several hundred euros extra. If the difference between normal and reversed orientation for 5x and 10x lenses is small I don't think it's worth the money to have 2 systems?

Correct and incorrect. Theoretically it does matter, there should be a "best distance". However you're not going to really see the difference, if there's any to begin with. However as a standard, it's good to follow thorlabs' recommendation, so just put around 70mm of tubing in between. BTW this gap is called the infinity space.

Those clamps you linked are not convenient at all. For the variable tubes, the external spanner ring gets caught inside the collar.

This makes it impossible to just slide the tubes out while the arca-swiss plate is attached. It's pretty annoying. I had an arca-swiss plate custom made that comes with M4/8-32 sized through holes, but still it's a nuisance.
This can be a better choice: https://www.thorlabs.com/thorproduct.cf ... mber=SM2TC
Not cheap!

It's not easy, neither is it quick, it's also expensive. I have one setup for my frankenmeasurescope and another for my other TL, and a third one for my microscope. Swapping tubes around is very annoying, especially when you need to flock them. Thorlabs' tubes are unflocked.

That said, if you get the distances right, you should be able to change between 245-flange and 140-flange easily. It's only a matter of revering the ITL200 holder and adding in about 110mm of tubes. The ITL200 does protrude the holder by around 5mm, typically. You can counter that by buying their M38 spanner ring to make sure the ITL200 is completely hidden in the holder.

Your impression to me was, you wanted the best image quality no matter what with the system. I personally don't recommend reversing the ITL200 at all, despite my older posts advocating for it. The difference isn't that drastic, you go from "eh could be better" corners to "eh still not good" corners on FX. If you use crop bodies or if you crop the bad corners out, it makes less sense. You can easily make a 2-3 shot focus stacked panorama, electronic shutter means your mechanical shutter won't even get worn out.

Example:


A very simple 3-shot stitch. Bad corners no more.
(This wasn't done with the ITL200, the corners were still not the best on my tube lens, I use my ITL200 mainly for my frankenmeasurescope.)

[nielsgeode]

Your impression to me was, you wanted the best image quality no matter what with the system. I personally don't recommend reversing the ITL200 at all, despite my older posts advocating for it. The difference isn't that drastic, you go from "eh could be better" corners to "eh still not good" corners on FX. If you use crop bodies or if you crop the bad corners out, it makes less sense. You can easily make a 2-3 shot focus stacked panorama, electronic shutter means your mechanical shutter won't even get worn out.

Yes and no. I'm looking for good image quality, but I don't need or want to bother to squeeze out the last 3% with a large amount of effort or costs.

Stitching is a thing for me. On the one hand it's tempting to make super high-resolution images. On the other hand it takes so much time and I'm almost never able to make a proper stitch out of the individual output stacked files I make (in the attempts I have done in the past). The problem is that I stack crystals with perfectly straight lines and even the tiniest of mismatch in the frames during stitching is obvious from a mile away.

My other main reason for stitching is when the magnification is slightly off, for example an 8mm crystal with my fullframe sensor and 5x magnification (7.2mm fov). However, given the amount of stacks I want to do it's best to not be too picky for most of them and only put a lot of time/effort in the very best onces.

I think the best is to get the cheaper (annoying) clamps and make a fixed setup with the tubes, clamps and arca plate. For that one I mount the ITL in normal orientation. If I ever want something else I will get a second clamp, tubes, arca plate so I can swap the entire 'thing' at once. Should be much more practical.

[Macro_Cosmos]

Yes and no. I'm looking for good image quality, but I don't need or want to bother to squeeze out the last 3% with a large amount of effort or costs.

Stitching is a thing for me. On the one hand it's tempting to make super high-resolution images. On the other hand it takes so much time and I'm almost never able to make a proper stitch out of the individual output stacked files I make (in the attempts I have done in the past). The problem is that I stack crystals with perfectly straight lines and even the tiniest of mismatch in the frames during stitching is obvious from a mile away.

My other main reason for stitching is when the magnification is slightly off, for example an 8mm crystal with my fullframe sensor and 5x magnification (7.2mm fov). However, given the amount of stacks I want to do it's best to not be too picky for most of them and only put a lot of time/effort in the very best onces.

I think the best is to get the cheaper (annoying) clamps and make a fixed setup with the tubes, clamps and arca plate. For that one I mount the ITL in normal orientation. If I ever want something else I will get a second clamp, tubes, arca plate so I can swap the entire 'thing' at once. Should be much more practical.

Since it's the corners, I'm not sure if that's even 3% extra.

For crystals, yeah I would avoid stitching. There's lots of very fine and thin crystals, software hates it. I assume you won't need edge-to-edge sharpness then. I know a someone who does excellent crystal stacks, most of his time is spent cleaning up the tiny dust particles and imperfections in post. He uses a 10x, a Canon 5Dmk2, and a Sony a6300.

Another method that just sprung to my mind is simply reversing the entire thing. Get yourself a short-ish A-S rail, like this one: https://www.reallyrightstuff.com/MPR-113-SOAR-rail

If you ever want to mount the ITL200 in retro, just swap the entire thing around. Add tubes to the front and take ones from the rear. Just make sure the tube assembly is clamped with the ITL200 sandwiched in the centre of 2 collars.
Here's mine. I personally use the long rail to coarsely focus. Simply rearrange the collars a bit. Focus can still be adjusted with the variable tube by loosening the collar.