Help Please with BHMJ to MM-11 lookalike

[dolmadis]

I purchased this 38kg monster unseen but for photographs. It came with no objectives, no eyepieces and no EPI Illuminator. But the BHMJ Focus Block is in perfect running condition. I took a chance based on the answer to the usual questions but with no warranty. There is some rust on retaining bolts etc., on the stand for me to stop/cure and the stage needs some work. The Trino is cleaner inside than you might expect. It all looks recently stripped down for sale of the lens system and the seller to me almost consigned it himself to the scrap skip thinking that nobody would surely want it.




As the title of my post suggests I wish to build a modified MM-11 'lookalike' for vertical use.

I will use initially my Nikon CFN Plan Objectives with CFW Eyepieces. The Nosepiece/Turret objective threads are M26 so I can use M26/RMS adapters. Then other adapters to mount enlarger lenses etc.,

I know very little about Olympus microscope systems and have read all I can on BHMJ focus blocks and direct projection from BHMJ on the forum.

And I would now welcome some help from Members before deciding on some options;

1. Retain the Trino? Would you recommend use in direct projection mode to a Canon DSLR? (Or optionally Oly EM-1 Micro 4/3.) What parts would be needed to be removed from the Trino (how)? Are there any named Oly parts (?) to be added? Other Parts?

2. Direct projection from nosepiece dovetail? Is this dovetail 42mm? I read the post from a few years ago where Members worked on a custom 42mm dovetail to M42 adapter. (Anyone have one they will never use for sale?) Or has anyone since used an off the shelf adapter (Where?). What other parts do I need please?

3. Is it practical to look out for a named Oly Part (?) for the EPI Illuminator? And usage value? (I have a Nikon Optiphot with EPI.)

I look forward to your help and guidance.

Many Thanks.



John

[Pau]

This seems a very good start point for a vertical setup!
Other people more used to Oly equipment will give more info and better advice, so I only can comment few points:

- the epiiluminator has inside a 180mm tube lens to work with infinite objectives, removing it the microscope is ready for 160 corrected objectives

- the epi condenser for the illuminator has been previously discussed: http://www.photomacrography.net/forum/v ... hp?t=32261

- The turret (nosepiece) is changeable, you can search one for RMS objectives for a BH2, maybe better than mounting adapters (both approaches will work)

[Ichthyophthirius]

Hi John,

The Olympus system for infinity metallurgical objectives is shown here: www.alanwood.net/downloads/olympus-bhm- ... ochure.pdf

As Pau said, the original setup included infinity-corrected objectives, the f=180 mm tube lens and compensating eyepieces.

If you want to use Nikon, you either have to use infinity-corrected objectives (and test how well the tube lens works for these) or remove the intermediate tube and use 160 mm objectives.

If this is the BH2-RLA brightfield/darkfield illuminator (looks like it) it would be great news. Darkfield epi illumination is vastly superior to brightfield epi but requires special objectives.

Regards, Ichty

[dolmadis]

Hi Pau and Ichty

Your observations on the EPI system places it as a jewel worth further investment. Thank you.

A BH2 RMS turret/nose piece is a good idea.

I hope those Members with experience of and information on direct projection on the Trino or nose piece come by.

I have tried quite a few of RAF's adapters in other contexts and they weren't quite right for my intended place.

Anyone...................is this an Oly Dovetail?

http://www.ebay.co.uk/itm/42mm-microsco ... SwImRYMV4p

Or does anyone else supply one?

Many thanks


John

[dolmadis]

Hi

I just found this one which proves that my spanish language skills are improving ( I am not serious I just looked at anything broadly matching in a Google search !!).

http://www.ebay.co.uk/itm/Cola-milano-a ... XQlgtSutFy

Sam suggests that a designation of a BH dovetail should be good for BH2.

Is BH a universal dovetail over the BH range?

Thanks


John

[Pau]

The spanish adapter is for T mount (m42x0.75) while the rafcamera's one is M42x1, more common with extension tubes, just different standards. (I natively understand Spanish )

Wait for measurements of a Oly user to be sure.

[Charles Krebs]

The replies you have gotten are dead on. I'll add a few more thoughts...

I once measured three Olympus BH dovetails and found the following:
A) 42mm, 6.02mm deep
B) 42.05mm, 6.05mm deep
C) 41.92mm, 6.07mm deep

I measured the narrow part of the sloped edge as 36.45mm

Olympus manufactured dovetails have a slightly chamfered edge at the widest point (where it measures 42mm). If that edge were simply beveled it would measure slightly larger (~ 42.9mm). The slope angle of the dovetail is 60 degrees.

The Olympus BH dovetail dimensions have been studied and measured in painstaking detail on the forum. Here is the most detailed thread:

http://www.photomacrography.net/forum/v ... hp?t=18614

The stand you show will make an excellent basis for a vertical "rig" (really... it already is!). But you do have some decisions to make.

The vertical illuminator component does "convert" it to an infinity scope with a 180mm tube lens. My experience has been that the results obtained with an Olympus 180mm tube lens when used with Mitutoyo or Nikon infinity objectives are just fine! (The Olympus tube lenses I have used are more recent, but no reason to expect any big change. As usual, try it and see... but I would not be too concerned in this regard.) The magnifications obtained with Nikon and Mitutoyo will be 10% lower than the designated magnification because of the tube length difference (180mm verses 200mm). The Olympus M-type infinity objectives that were made at the time of this illuminator required chromatic correction, but that was applied in the eyepieces not the tube lens (as is currently the case with Zeiss and Leica infinity systems). So it means no chromatic problems with current production Olympus objectives, Nikon CF or Mitutoyo. (A downside might be that there are many good deals on the older Olympus M-type infinity objectives, but then you get into the situation where you really should track down appropriate NFK photo-eyepieces or go afocal. Not fun or sometimes even practical.)

I am certainly a big "fan" of direct projection. But I have never tried it with the Olympus BH2-TR30 head you picture since the optics on my BHS require the use of NFK photoeyepieces. By removing the screws at the top on the trinocular tube you can remove the upper section (at the obvious division line). An external measurement of this section gives about 37mm, so it is unlikely that you could position a DSLR body in position for direct projection that would be parfocal with the eyepieces (DSLRs have a body depth around 44mm to 46.5mm). It certainly would appear to provide adequate working distance to accommodate the camera body depth of some of the mirrorless camera bodies out there, like the Olympus you mention (MFT has a body depth of 19.25mm). But naturally it would require a DIY mount adaptation.

[dolmadis]

Many Thanks Charles for the information.

I think that I will go with all of the options presented after refurb of the stand.

Sam, the seller at the Ebay adapter above, confirms that his dovetail is BH2 (to T2 and another adapter T2 to M42) but I do note the variation that you mention above.

I did find that amazing thread you mention. Luckily for us in the UK there is a UK member of the forum who I can ask if he can assist me with mods in case of need (hope).

So I can use my finite Nikon CFN Objectives (and others) on a direct projection from an RMS BH2 turret (replacement) with some experimentation on tube height to camera.

And the Olympus BH2-TR30 head together with the BH2-RLA (does looks like it Ichty and I am checking this out with the additional options you mention) gives wider benefits.

I have three infinite objectives, a Mitutoyo QV 2.5x, Mitutoyo Apo 10x 0.28 and a Nikon CF Plan 10X 0.30 WD 16.5. So I have no need right now to continue my quest for an economic source of compatible 52mm tubes to use with Raynox. I have an adapter from Astro sources that fits over a "trino chimney" which ends in a "42" thread so I can remove the upper part you mention and experiment.

Thank you so much Pau, Ichty and Charles for the help.

BR


John

[dolmadis]

I have removed the BH2-RLA (vertical illuminator) and detached from the Trino Head BH2-TR30 with a little struggle as the dovetail had jammed during transit.

Reinstalled on the BHMJ Nosepiece in place of the BH2-TR30

Reason for this would be to be able to try the option of direct projection from infinity objectives through the vertical illumination unit housing the infinity tube lens.

But does the illumination have to be provided through the BH2-RLA? Or can BF be selected and the diffused lighting of the subject be provided at stage level from LED's/Fibre sources?

I have used an LED Torch to confirm that a light path from beneath the BH2-RLA will exit from the top of the BH2-RLA. BF seemed to make no difference.

Is that a realistic test of what I want it to do?

(Taking it step by step and as I spend some time in Cyprus they say "sigar, sigar" = slowly,slowly.)

Many Thanks


John

[dolmadis]

Another day another question pops up if anyone can help.

Gary in this project (posted above by Pau) has been very helpful by PM.

http://www.photomacrography.net/forum/v ... hp?t=32261

Am I right in concluding that without the specific Olympus Objectives (mentioned by Ichty) that there will be nothing gained by adding the light source to the BH2-RLA for use with other infinity objectives?

I would welcome any thoughts that forum members might have about adding a stepper without drilling into the bottom of the BHMJ Focus block.

The "dovetailed rack" (best I can come up with) part of the focus mechanism rattles a bit laterally. Any ideas on how to fix this please? Can't find any clues on Google or Forum search.

Thanks


John

[ChrisR]

Am I right in concluding that without the specific Olympus Objectives (mentioned by Ichty) that there will be nothing gained by adding the light source to the BH2-RLA for use with other infinity objectives?

As I understand it (I'll be happy to be corrected) both Nikon and Olympus incident Brightfield/Darkfield objectives have a similar external annulus for illumination. The mirror in the epi lighting unit directs light down through that, optionally as well as the centre.
There is bound to be some overlap, but some difference, in the dimensions of the annuli (and the threads).
Nikon infinite BDs are 27mm threads
Nikon finite BDs are 26mm, 210mm tube length.

With the "wrong" manufacturer of BD objectives, I can imagine possible problems with illumination getting where it shouldn't ( & bouncing around) as well as not getting where it should. The length/spaces produced by any extra adapters could compound that.

For brighfield incident illumination the rear aperture of the objective is often quite small, so I wouldn't expect much problem. That would apply to Nikon , Mitutoyo, whatever.


I doubt there's much need to drill the BHMJ block. You have to support a motor somewhere, it's true. You could use a belt so the motor is somewhat remote.

I can't advise about dismantling the running part of the BHMJ, which as I remember it has balls running between rods. I did dismantle a similar one, rotating the rods 180º so a new side was presented to the balls. After cleaning and regreasing it ran much better. My block has four(?) painted-up grub screws externally, on one side, which I have successfully use to slightly tighten a (similar Oly) block. Small movements only, about 10º at a time to all four together.

[dolmadis]

Thanks for the great reply Chris. I will be looking out for a "reasonably priced" Nikon BD Infinite to try.

BR

John

[ChrisR]

There are some rear-end pictures at ebay item 291943593319. Somewhat damaged!

[dolmadis]

I just love the Description!...........In good condition!!..........no returns