Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

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Hobbyst46
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Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#1 Post by Hobbyst46 » Sun Aug 01, 2021 4:33 pm

Hello all,
In 2017, Robert Otoole tested and suggested a simple inexpensive macro photography arrangement which comprised:
1. Camera body + suitable camera-to-tubing adapter (say, to M42)
2. An extension tube
3. A tube->RMS adapter
4. An inexpensive modern Plan 4X, 160mm objective with RMS thread,

All combined to give the appropriate 160mm distance from the camera sensor.
He showed very nice hand-held macro photos.

I fantasize on imitating his setup to image large diatoms. I just need items no 2 and 3 of the above list.
I already have 16mm+10mm extension rings and, together with my EOSM->M42 adapter, the total length is already 7-8cm
from the sensor (if the sensor is at the midpoint of the mirrorless camera thickness).
So, given that the 4X objective itself is ~3cm long, I need a ~6cm long extension tube to complete the distance of 16cm.
I found this on ebay:
https://www.ebay.com/itm/384184630819?_ ... %3A2047675

What do you think ?
Or should I better opt for a combination of shorter extension tubes ? I am trying to try this on the cheap... so no helicoids...

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#2 Post by Scarodactyl » Sun Aug 01, 2021 5:11 pm

A good m42 helicoid can be had for about 25 bucks, nothing too crazy. This type of setup is quite forgiving and should be easy to put together. You'd probably still want it to be on some sort of focus mount though--dof is quite thin at 4x for handheld work.

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#3 Post by patta » Sun Aug 01, 2021 5:22 pm

Most probably you already have items #2 and #3:
RMS adapter: microscope nosepiece
Tube: microscope tube

A microscope is the same setup, readily mounted with a solid stand, fine focus, illumination?
If one doesn't have a microscope, ok, it is cheaper to get only the 4x and mount it directly to the camera with tube spacers.
I've done the O'toole setup, but it is normally a pain because of difficulty in focus and vibrations. More than the helicoid, a focus rack is really helpful.
If you have a microscope, mount the camera on it, focus becomes easy and no more vibrations.
Look what crazy people do to get fine focus on the cheap
https://www.microbehunter.com/microscop ... ck#p105175

For anything mounted on a slide, I'd prefer the microscope
For super-macro of butterflies on the garden, or 3D macro subjects, ok, the O'toole is lighter and more portable, but needs more patience and superhuman steady hands..
Last edited by patta on Sun Aug 01, 2021 6:11 pm, edited 2 times in total.

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#4 Post by patta » Sun Aug 01, 2021 5:45 pm

Ok, sorry, if you want to make this setup
with tubes, non the one you linked, it is for telescope eyepieces; take just T2 tubes
https://www.ebay.co.uk/itm/124624199054 ... Sw4nNgSSKx
and a T2- rms adapter
https://www.ebay.co.uk/itm/372327978082 ... XQltxQ5vKZ
Be careful that there are around TWO M42 types of threads, the M42x1 (old camera mounts) and the T2, M42x0.75 (Telescope adapters, Tamron etc). stick to one, for example T2

yes it's getting expensive. Maybe more honest sellers on Aliexpress. Or better material at Rafcamera.
So, first you can also try out to temporarily mount the 4x objective with a cardboard tube & tape to the tubes you have, should work.

The 160mm, it is the distance between the 4x objective FLANGE (not the tip) and the sensor.

A valid alternative to tubes is to get a bellow rail and adapters, so you can adjust the distance at will; in this case they're M42x1
https://www.ebay.co.uk/itm/114275487485 ... SwBfhe9KX0

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#5 Post by Scarodactyl » Sun Aug 01, 2021 6:06 pm

Generic m42x1 spacers are pretty cheap if you're willing to wait for them to come in.
Bellows are good too, but I have found mine kind of annoying to use because the rail can stick out further than my working distance.

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#6 Post by Hobbyst46 » Sun Aug 01, 2021 6:59 pm

Thanks a lot, patta and Scarodactyl, for the enlightening remarks and suggestions.
I will definitely think it over and re-consider.

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#7 Post by patta » Sun Aug 01, 2021 7:00 pm

Oh another funny option is the Lomo "Mir 2"
it is a drawtube microscope; has built-in RMS adapter, tube and focus.
if you find a way to mount it to the camera
https://www.ebay.co.uk/itm/201686875878 ... SwNRdX-rVW
(should cost <50$)

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#8 Post by Hobbyst46 » Sun Aug 01, 2021 8:21 pm

patta wrote:
Sun Aug 01, 2021 5:22 pm
Most probably you already have items #2 and #3:
RMS adapter: microscope nosepiece
Tube: microscope tube
A microscope is the same setup, readily mounted with a solid stand, fine focus, illumination?
That is all true of course. The issue is, that the phototube on my old trinocular is long, so the distance from the objective flange to the top of the phototube is already ~15cm, and even with the minimum number of camera->tube adapters, the total length (thanks for correcting me earlier)
would be significantly longer than 16cm.

Another option is to install the camera on top of one of the bino tubes; by means of an adapter tube, of outer diameter 23.2mm, and its end - a male M42 (or T2, yes I am aware of the subtle difference); the total distance will be only slightly longer than 16cm, maybe. The adapter is a sort of glass-less, thin shoulder eyepiece attached to a male M42...

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#9 Post by Hobbyst46 » Mon Aug 02, 2021 6:57 am

Hobbyst46 wrote:
Sun Aug 01, 2021 8:21 pm
...to install the camera on top of one of the bino tubes; by means of an adapter tube, of outer diameter 23.2mm, and its end - a male M42 (or T2, yes I am aware of the subtle difference); the total distance will be only slightly longer than 16cm, maybe. The adapter is a sort of glass-less, thin shoulder eyepiece attached to a male M42...
Like this "23.2mm T Mount Microscope Lens Adapter Ring for Canon E Mount Camera M42x0.75mm"
for example; with/without the T2/M42 ring
Attachments
23.2mm-M42 adapter.jpg
23.2mm-M42 adapter.jpg (26.24 KiB) Viewed 8561 times

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#10 Post by patta » Tue Aug 03, 2021 7:50 am

Aha, now I understand
some more troubles:

1) Yes, the adapter you've linked is ok, but: the distance is even longer! The eyepiece ends at nominal 160mm, so mounting the adapter will put the sensor even more far away. The adapter in the photo seems to have no glass in it

2) the flange- sensor distance should be 150mm, not 160. 160 is the tube length, but the image is 10mm below (for DIN).

To get direct projection on the Eos M sensor:

you either smash the Canon M over the phototube

Or saw shorter the phototube

Or don't care about those 160/150mm and just mount it on the phototube, with shortest adapter you can; it will be 180mm or so
We'll all disapprove, the image won't be in same focus with the eyepieces, but works.

Or use eyepiece projection, or a camera adapter

Or, a nice new thing, you use a telescope Barlow lens as adapter, it lengthens the tube (similar to Homal eyepiece)
That is maybe what you described in post #8

About that, you have a trinocular head.
Does it have a lens at the base? Like, 1.25x? If yes, then the length becomes mòre than 150mm, and you may manage to mount the camera on the phototube at correct distance

If you have already a Macro lens for the EosM, you can mount camera w macro, so it focuses in the phototube, exactly where the image should be at 150mm (use the macro lens as projection relay)

The Otoole setup for direct projection is becoming more attractive...
Sorry if I'm just repeating things you know better than me...
Last edited by patta on Tue Aug 03, 2021 8:26 am, edited 2 times in total.

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#11 Post by patta » Tue Aug 03, 2021 8:06 am

Did you check where the image in the phototube actually lies?

Focus to a nice slide at the eyepiece
Take out one eyepiece, and hover it by hand over the phototube
Where you see the image in focus, there it is; 10mm below the eyepiece shoulder

Be careful not dropping the eyepiece in the phototube, or something expensive will be smashed (sad personal experience)

If the image is some cm over the phototube, you're in business!

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#12 Post by viktor j nilsson » Tue Aug 03, 2021 8:35 am

Haven't read this in detail. But did you consider the option of removing the head, and replacing it with an empty tube of the right length? It's a very convenient way of getting a stable vertical setup.

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#13 Post by patta » Tue Aug 03, 2021 8:36 am

Even one more option, then I'll stop spamming

The phototube of Zeiss GFL looks like it can be screwed away
In that case, you 3D print a tube of right length, or find the adapters needed, so to get direct projection.

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#14 Post by MichaelG. » Tue Aug 03, 2021 12:41 pm

patta wrote:
Sun Aug 01, 2021 7:00 pm
Oh another funny option is the Lomo "Mir 2"
it is a drawtube microscope; has built-in RMS adapter, tube and focus.
if you find a way to mount it to the camera
https://www.ebay.co.uk/itm/201686875878 ... SwNRdX-rVW
(should cost <50$)
I have one of those …
Please be aware that it has nothing that I would call a focus mechanism
i.e. there are no gears or levers.

In my limited experience: Extreme macro is much easier if you focus by adjusting the subject distance.
… Helicoids and Bellows are best reserved for adjusting magnification and/or optimising tube length.

MichaelG.
.
.
From an old LOMO catalogue
From an old LOMO catalogue
00F89652-A1D5-48D8-9B17-DB736EA326EB.jpeg (89.61 KiB) Viewed 8495 times
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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#15 Post by Hobbyst46 » Tue Aug 03, 2021 6:26 pm

Thank you patta, Viktor and MichaelG for the info and discussion
patta wrote:
Tue Aug 03, 2021 7:50 am
1) Yes, the adapter you've linked is ok, but: the distance is even longer! The eyepiece ends at nominal 160mm, so mounting the adapter will put the sensor even more far away. Thanks!
The adapter in the photo seems to have no glass in it It does not
To get direct projection on the Eos M sensor:
you either smash the Canon M over the phototube :shock:
Or saw shorter the phototube Impractical, since I only have one photo tube which, I need for ordinary photomicrography.

Or don't care about those 160/150mm and just mount it on the phototube, with shortest adapter you can; it will be 180mm or so Possibly, but I prefer to play by the book, 160mm

That is maybe what you described in post #8
About that, you have a trinocular head.
Does it have a lens at the base? No.
If you have already a Macro lens for the EosM, No
The Otoole setup for direct projection is becoming more attractive...
Sorry if I'm just repeating things you know better than me...It is all for a good purpose and I benefit from the comments and discussion.
So, from the combined comments and opinions about the O'toole setup:
1. A microscope is the way to go, to achieve accurate focus
2. Find a short phototube (actually, there exists a Zeiss single vertical tube head for these microscopes
3. And shorten it even further, to combine it with the glass-less 23.2mm->M42 adapter shown in the above photo, and somehow achieve a fixed, glass-less 150mm path.

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#16 Post by viktor j nilsson » Tue Aug 03, 2021 7:24 pm

I think that is one good option.

Another would be to remove the head, and replace it with one of these + some M42 extension tubes and maybe a focusing helicoid for fine tuning the tube length:

https://rafcamera.com/adapter-dt44mm-to-m42x1m?amp=1

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#17 Post by MichaelG. » Tue Aug 03, 2021 7:32 pm

Hobbyst46 wrote:
Sun Aug 01, 2021 4:33 pm
Hello all,
[…]
I already have 16mm+10mm extension rings and, together with my EOSM->M42 adapter,
[…]
I found this on ebay:
https://www.ebay.com/itm/384184630819

What do you think ?

.

Returning to your opening post ^^^

Please be warned: That ebay listing wrongly states that the thread is M42
But the detailed description identifies it as 0.75mm pitch [which is the T2 thread]
It will not fit your M42 adapter, or tubes.
M42 camera thread is 1mm pitch.

MichaelG.

.
Edit: __ I suggest searching ebay for ‘M42 Extension Tubes’ and grabbing a couple of sets that take your fancy.

Every tinkerer should have a few of these.
Last edited by MichaelG. on Tue Aug 03, 2021 7:48 pm, edited 1 time in total.
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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#18 Post by Hobbyst46 » Tue Aug 03, 2021 7:47 pm

MichaelG. wrote:
Tue Aug 03, 2021 7:32 pm
Please be warned: That ebay listing wrongly states that the thread is M42
But the detailed description identifies it as 0.75mm pitch [which is the T2 thread]
It will not fit your M42 adapter, or tubes.
M42 camera thread is 1mm pitch.
MichaelG.
Thanks, MichaelG. On behalf of previous comments, For other reasons, I abandoned the telescope adapter option.

Indeed, the Rafcamera adapter shown in the link from Viktor has an M42x1 thread.
My canon EOS-M camera mount ends in an M42 thread, but I must verify the T2 vs M42 in all these connectors. I have an M42->T2 ring adapter as well.

I fear that some of those very cheap thin-walled black adapter rings are randomly labelled "T2" or "M42" irrespective of their true size... just suspects
Last edited by Hobbyst46 on Tue Aug 03, 2021 7:55 pm, edited 1 time in total.

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#19 Post by MichaelG. » Tue Aug 03, 2021 7:51 pm

Hobbyst46 wrote:
Tue Aug 03, 2021 7:47 pm

My canon EOS-M camera mount ends in a T2 thread, M42x0.75.
.

Apologies … my misinterpretation.

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#20 Post by Hobbyst46 » Tue Aug 03, 2021 7:56 pm

No, a useful reminder ! The more talks about technical details, the better.

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#21 Post by Hobbyst46 » Tue Aug 03, 2021 8:02 pm

The Zeiss Standard head dovetail is of 44mm outer diameter. I measure 43.5mm on mine, but never mind. The same diameter on the dovetail of the simple condenser. I imagined I could utilize the dovetail from a "just for parts" simple condenser to build a head-phototube adapter and save me the need for a Rafcamera or similar adapter ($27 plus shipping).
BUT - the two dovetail outer tapers are not identical. That of the condenser is all the way conical, that of the head has a short conical section and a straight section. So, the condenser's dovetail does not fit the microscope head.

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#22 Post by Scarodactyl » Tue Aug 03, 2021 9:27 pm

This is not super expensive but not a perfect budget setup either unless you find an uncommon deal
https://www.photomacrography.net/forum/ ... 25&t=43640
Quite versatile though, easy to mount a variety of lenses.

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#23 Post by patta » Thu Aug 05, 2021 11:53 am

Post #16 seems to me the cleanest solution
Post #22, that is really great!
To keep well below 30$ budget.. that will need 3D printing the adapter, or gluing PVC pipes; either dovetail as post #16, or just the phototube. If you can make the drawing of the adapter, online 3D printing services are rather inexpensive. Whether the screw thread or the dovetail will fit exactly, that's a gamble! Just like getting a "for parts" used components...

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#24 Post by Hobbyst46 » Thu Aug 05, 2021 8:17 pm

patta wrote:
Thu Aug 05, 2021 11:53 am
Post #16 seems to me the cleanest solution Agreed, if I can find one at a reasonable price including postage
Post #22, that is really great!
To keep well below 30$ budget.. that will need 3D printing the adapter, or gluing PVC pipes; either dovetail as post #16, or just the phototube. If you can make the drawing of the adapter, online 3D printing services are rather inexpensive. Whether the screw thread or the dovetail will fit exactly, that's a gamble! Just like getting a "for parts" used components...
Will try to remove the head and experiment with makeshift dovetail adapters. I can wrap a 1mm OD or so wire around a dovetail taken from a simple Zeiss condenser (the simplest there is), and if it fits into the top dovetail on the stand, add the tubular adapter parts to find out the potential of the camera-160mm-4x objective combination.

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#25 Post by Chas » Fri Aug 06, 2021 2:40 pm

These are quite nice and ergonomic .. I have some black craft rubber foam inside it to kill reflections :
https://www.ebay.co.uk/itm/223966885284 ... Swu1VW53uk
Pic:
Cone 640 480.jpg
Cone 640 480.jpg (33.99 KiB) Viewed 8252 times
Last edited by Chas on Fri Aug 06, 2021 7:16 pm, edited 2 times in total.

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#26 Post by MichaelG. » Fri Aug 06, 2021 4:04 pm

Hobbyst46 wrote:
Sun Aug 01, 2021 4:33 pm

[…]

4. An inexpensive modern Plan 4X, 160mm objective with RMS thread,

All combined to give the appropriate 160mm distance from the camera sensor.
He showed very nice hand-held macro photos.

I fantasize on imitating his setup to image large diatoms.
Please forgive the delay in mentioning this, but … are you happy that 4x is the appropriate magnification ?

A ‘large’ diatom of [say] 300 microns would only produce a region of interest of 1200 on your camera sensor
… is that enough pixels ?

MichaelG.
.

Edit: __ according to this : https://www.digicamdb.com/specs/canon_eos-m/ the pixel pitch of the EOS-M is 4.29 microns
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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#27 Post by Hobbyst46 » Fri Aug 06, 2021 9:21 pm

MichaelG. wrote:
Fri Aug 06, 2021 4:04 pm
Please forgive the delay in mentioning this, but … are you happy that 4x is the appropriate magnification ?
A ‘large’ diatom of [say] 300 microns would only produce a region of interest of 1200 on your camera sensor
… is that enough pixels ?
Edit: __ according to this : https://www.digicamdb.com/specs/canon_eos-m/ the pixel pitch of the EOS-M is 4.29 microns
Not happy, yet curious how bad will the image be; maybe try a 10X objective as well as 4x.
Just playing ("tinkering" ?) with inexpensive macrophotography without proper macro equipment....

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#28 Post by MichaelG. » Fri Aug 06, 2021 9:33 pm

Simple arithmetic says that the 300 micron diatom would only be 280 pixels on your camera at 4x

Obviously worth a look, but …

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#29 Post by MichaelG. » Sat Aug 07, 2021 5:46 am

Also worth noting this, which Viktor has posted on another thread:
viewtopic.php?p=107931#p107931

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Re: Will the Otoole "extension tube+4x objective" macro setup perform on diatoms ?

#30 Post by Hobbyst46 » Sat Aug 07, 2021 8:46 am

MichaelG. wrote:
Fri Aug 06, 2021 9:33 pm
Simple arithmetic says that the 300 micron diatom would only be 280 pixels on your camera at 4x :(

Obviously worth a look, but …

MichaelG.
On behalf of the bolded words, I am playing with the thought... and counting every $ of expenditure.

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