Mitutoyo 10 Objective Tube Lens Tests

[RobertOToole]

Excellent Rik, thanks for the explanation.



Robert

[hero]

This discussion is relevant to my situation as the purchaser of one of Robert's Mitutoyo 10x objectives (thanks!); I now find myself in the peculiar circumstance of having an objective but...no tube lens. I have scoured the forums and looked at all kinds of arcane setups and tests but am no closer to deciding on what to do.

I am also a bit embarrassed to say that I don't even know which threaded mount or adapter is needed to fix the objective to the tube lens. I'm guessing it's M40? If so, where to get this?

Think of me as a clean slate: I have a full frame EF mount camera on one end, and a 10x BD Plan on the other, and need to connect the two without causing a mild case of insanity.

I suspect that the Raynox DCR 150 is the way to go....Wemacro offers this: https://www.wemacro.com/?product=raynox ... -tube-lens which is quite economical, but it doesn't have the right threaded adapter. Then there's this from MJKZZ: http://www.mjkzz.com/product-page/varia ... ith-clamps which looks more solid, but again, not sure about the thread size.

If this helps, moderate field curvature is not an issue for my use case, but chromatic aberrations must be minimized, even at the expense of some corner sharpness. I don't need to push the magnification down, but I do want the image circle to cover the full frame sensor.

[RobertOToole]

Mitutoyo 10x 0.28 + ITL200 Normal mount at infinity has field curvature + soft corners + CAs. Poor results overall but the center is sharp.

Mitutoyo 10x 0.28 + ITL200 Reverse mount at infinity has perfect sharp corners and zero CAs and only some slight curvature.

Robert, can you clarify what distance(s) you were using between objective and ITL200?

It's not in front of me now but have a 75mm long tube with only internal/female threads to use as my standard TL to objective tube since the ITL200 adapter has only external/male threads and 75mm seems to work well with almost all of the TLs that I use.

The reason I ask is that I recently noticed in reviewing some of my early tests, using a distant object and aperture to stand in for an idealized objective, that in the corner of an FF frame,

The Thorlabs has very little color fringing when used at recommended separation (upper right), but develops significant color fringing when used with no separation (upper left).

I would not doubt that, I did try a few different TL-Obj extension lengths for all the tube lenses in my tube lens test that I shared here and only 1 or 2 performed better with minimal separation. I just checked my test online and I noted that fact for a few lenses like the Century Diopters. Minimal separation resulted in increased CAs. I should have just went with Thorlans advice and saved myself a lot of work!

The Mitutoyo has more color fringing than the Thorlabs under recommended separation (lower right), but it doesn't change much and has less fringing than the Thorlabs when used with no separation (lower left).

So, even without an objective, with the ITL200 it obviously matters quite a lot where the exit pupil of the objective is located.

--Rik

Thanks for the notes.


Robert

[RobertOToole]

This discussion is relevant to my situation as the purchaser of one of Robert's Mitutoyo 10x objectives (thanks!)

Thank you.

One good thing about that objective is that it was tested a few times and it a really good performer. On Ebay it can be a gamble with some of the sellers.

I now find myself in the peculiar circumstance of having an objective but...no tube lens. I have scoured the forums and looked at all kinds of arcane setups and tests but am no closer to deciding on what to do.

This test was done in August:

https://www.closeuphotography.com/tube-lens-test

I am also a bit embarrassed to say that I don't even know which threaded mount or adapter is needed to fix the objective to the tube lens. I'm guessing it's M40? If so, where to get this?

M40 x 0.706 pitch (36 TPI) adapters with these threads can be easily found on Ebay. I will grab you a link.

Think of me as a clean slate: I have a full frame EF mount camera on one end, and a 10x BD Plan on the other, and need to connect the two without causing a mild case of insanity

.

There are lots of good posts here on the forum I can post links for a few.

I suspect that the Raynox DCR 150 is the way to go....Wemacro offers this: https://www.wemacro.com/?product=raynox ... -tube-lens which is quite economical, but it doesn't have the right threaded adapter. Then there's this from MJKZZ: http://www.mjkzz.com/product-page/varia ... ith-clamps which looks more solid, but again, not sure about the thread size.

Raynox are excellent but mounting these can be a hassle.

If this helps, moderate field curvature is not an issue for my use case, but chromatic aberrations must be minimized, even at the expense of some corner sharpness. I don't need to push the magnification down, but I do want the image circle to cover the full frame sensor.

That should not be a problem.

There was a seller on Ebay with the ITL200 tube lens for $169, this was one of the best lenses in my test. I will check this for you now.

[RobertOToole]

Tube lens test on a full frame camera:

http://www.photomacrography.net/forum/v ... hp?t=23898

How to setup a tube lens:

http://www.photomacrography.net/forum/v ... hp?t=12147

The set-up that I use:

https://www.closeuphotography.com/52mm-setup

[RobertOToole]

Sorry the Thorlabs ITL200 tube lens seller on Ebay does not list that lens any longer:

https://www.ebay.com/sch/dgold32/

[RobertOToole]

RAf Camera has a 52mm > M40 36 tpi adapter:

https://www.ebay.com/itm/M40x36tpi-fema ... 3337159026?

Rise (UK) 42mm to M40 x 0,75 adapters will allow a Mitutoyo BD Plan objective to fully thread even though the threads are technically wrong. These are easy to find on Ebay.

[mjkzz]

and with 245mm extension implies total magnification to be more than 12.25x (because of flange distance), to validate that, maybe shooting a ruler to get actual magnification.

Peter,

With 245mm of extension on the ITL200 in reverse with the Mitutoyo 10x I measured 2.33 mm or 10.08x at the sensor.

OK, the 245mm is when you reverse it. But still . . . well, I gave up. Thanks for your hard work.

I know what you mean Peter don't worry. That is why I am testing even if it doesn't always make sense.

When used in its specified orientation, the ITL 200 has a weakly telephoto design: the lens-to-sensor distance is less than the focal length.

When the lens gets reversed, it becomes a weak retrofocus design: the lens-to-sensor distance is then more than the focal length.

In both cases, when the rear lens is focused at infinity the overall magnification is determined by the ratio of focal lengths of the front and rear lenses. The lens-to-sensor distance is not relevant except that it must be whatever is needed to make the rear lens focus at infinity.

BTW, for me the published setup of the ITL200 in fact did have the correct distances, to within measurement error of my experimental results with infinity focus. See https://www.photomacrography.net/forum/ ... 772#235772 for more information. If I read the surrounding discussion correctly, some of Robert's early observations had been contaminated by accidentally grabbing a wrong lens at one point.

So your results imply I need to learn more about optics, ie, I believe real experiments over my understand of theory

Yep. The part you need this time is about telephoto and retrofocus designs, in particular the relationship between principal planes and the lens barrel.

--Rik

Wow, cool, thanks Rik, learning new stuff everyday here!

[typestar]

... It would be interesting to test all objectives with a very short tube lens, short enough to show at least a trace of vignetting. A 90mm or 100mm or 105mm lens, for example.

Thanks for the idea Lou....
I can try each objective with one good shorter tube like a Sigma 150mm or the Makro-symmar 120.

Dear Robert, I am also very exited in your 10x testing
AND - not only because of a shorter overall setup length -- many of us are interested in pushed down lens with VERY short tube lenses, from 90 mm to max. 135 mm.
So - could you consider in this 10x testing also the 20x Mitutoyo M Plan APO -- way pushed down also -- because of its large image field... ? Or do you think its another test necessary... ?

Good luck for your work!

All the best: christian

[RobertOToole]

... It would be interesting to test all objectives with a very short tube lens, short enough to show at least a trace of vignetting. A 90mm or 100mm or 105mm lens, for example.

Thanks for the idea Lou....
I can try each objective with one good shorter tube like a Sigma 150mm or the Makro-symmar 120.

Dear Robert, I am also very exited in your 10x testing
AND - not only because of a shorter overall setup length -- many of us are interested in pushed down lens with VERY short tube lenses, from 90 mm to max. 135 mm.
So - could you consider in this 10x testing also the 20x Mitutoyo M Plan APO -- way pushed down also -- because of its large image field... ? Or do you think its another test necessary... ?

Good luck for your work!

All the best: christian

Hi Christian,

Yes I do plan to run the 10x lenses with a couple of short tube lenses.

Maybe Makro Symmar 120 and something shorter.

I also plan to run a test on 20x Objectives later this year once I am done with the 10x units.

[Guppy]

Hello

I have a question for Robert
https://www.closeuphotography.com/tube-lens-test

Tube Lenses shorter than 200mm
Thorlabs ITL200
Reverse mount:
Overall: 9.6
Center: 8.5
Corner: 8.5
Chromatic Aberration Control: 10

8.5 + 8.5 + 10 = 27
27 / 3 = 9 !
and not Overall: 9.6

Or is Overall 9 ?

Thanks
Kurt

[RobertOToole]

Hello

I have a question for Robert
https://www.closeuphotography.com/tube-lens-test

Tube Lenses shorter than 200mm
Thorlabs ITL200
Reverse mount:
Overall: 9.6
Center: 8.5
Corner: 8.5
Chromatic Aberration Control: 10

8.5 + 8.5 + 10 = 27
27 / 3 = 9 !
and not Overall: 9.6

Or is Overall 9 ?

Thanks
Kurt

Sorry for the typo, I was tired at that point having been testing for a few hours.

I think the score for the ITL200 short focus is better than 9. Its up closer to 9.5 or 9.6 and up with the best lenses I tested.

Thanks.

[Guppy]

Hallo

I use full frame Nikon D810 with MITUTOYO M Plan Apo 10X/0.28 ?/0 f=200 and ITL200 revers.

Tube Lenses shorter than 200mm is in my measurements (8:1)
in the corner unacceptable.

Reverse with 230mm (10:1) is the resolution in the corner more than 80% from the center.
That is an acceptable result for me.

Kurt

[Guppy]

Hello

Results:
MITUTOYO M Plan Apo 10X/0.28 ?/0 f=200 and ITL200 revers
Distance between lens and ITL200 revers = 80mm
Distance between ITL200 revers and Sensor (Nikon D810) = 230mm
10:1 with Nikon D810 full frame
Center = 950 LP/mm
Corner = 780 LP/mm

MITUTOYO M Plan Apo 20X/0.42 ?/0 f=200 and ITL200 revers
Distance between lens and ITL200 revers = 80mm
Distance between ITL200 revers and Sensor (Nikon D810) = 220mm
20:1 with Nikon D810 full frame
Center = 1350 LP/mm
Corner = 1300 LP/mm, with litle, litle bit of CA, but not disturbing
The corners are a bit darker, but that's no problem

Kurt

[rjlittlefield]

Kurt, just to clarify...

Results:
MITUTOYO M Plan Apo 10X/0.28 ?/0 f=200 and ITL200 revers
Distance between lens and ITL200 revers = 80mm
Distance between ITL200 revers and Sensor (Nikon D810) = 230mm
10:1 with Nikon D810 full frame
Center = 950 LP/mm
Corner = 780 LP/mm

MITUTOYO M Plan Apo 20X/0.42 ?/0 f=200 and ITL200 revers
Distance between lens and ITL200 revers = 80mm
Distance between ITL200 revers and Sensor (Nikon D810) = 220mm
20:1 with Nikon D810 full frame
Center = 1350 LP/mm
Corner = 1300 LP/mm, with litle, litle bit of CA, but not disturbing
The corners are a bit darker, but that's no problem

Your LP/mm numbers refer to resolution on subject, right?

--Rik