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Leitz/Leica/other microscope stand for photomacrography?

 
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enricosavazzi



Joined: 21 Nov 2009
Posts: 1212
Location: Borgholm, Sweden

PostPosted: Thu Mar 04, 2010 2:17 am    Post subject: Leitz/Leica/other microscope stand for photomacrography? Reply with quote

I am considering buying a second-hand microscope stand to modify for photomacrography (including stacking) above approximately 10x. I already have adequate stands for lower magnification, and most of the RMS photomacrographic lenses and microscope objectives for this use. I plan to put the microscope stand (modified by taking out any tube lenses, binocular head etc.) under an Aristophot stand that carries the camera and bellows to isolate the subject stage from camera vibration. I already have a fully equipped Zeiss Photomicroscope 1, but this is likely too heavy and large to put under a Multiphot/Aristophot stand (my Photomic has the bulky fluorescence add-on base with pumpkin illuminator and normal halogen illuminator sticking out at the rear), and has too much optical stuff between objective carrier and photo port to quickly switch between photomicrography and photomacrography.

I am considering a Leitz Laborlux or a Leica Galen stand, which are relatively small without being toy-like. Which one would offer the most advantages for photomacrography? (e.g., long travel of the coarse focusing rack, fine focusing that does not need to be backed up at the end of a short movement range). I am familiar with the older one-knob fine/coarse control of older Leitz stands, but both above types have dual knobs, and I don't have direct access to one of these stands.

I am aware of the Nikon and Olympus focusing racks often used in photomacrography, which have internal planetary gears. The Nikon Labophot stand is usually equipped with an equivalent focusing rack, but is rather difficult to find in good condition. The Olympus B* stands seem to be equipped with similar racks. Is any of these stands clearly better for photomacrography than the Leitz/Leica alternatives?
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Charles Krebs



Joined: 01 Aug 2006
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Location: Issaquah, WA USA

PostPosted: Thu Mar 04, 2010 11:51 am    Post subject: Reply with quote

Enrico,

I have no familiarity with the Leitz stands you are talking about. But have pretty significant experience with the Nikon Labophots and Olympus BH series ("A" and "2"). Any of these would work nicely for you needs. Both have full length fine focus travel, with no need to ever "back-track" the fine focus. The Olympus dial is calibrated 2 micron per tick mark, and visually it's not hard to set 1 micron intervals, so you can work easily with a 40X objective. (Never really checked the Labophot, but if you are interested I can).

If buying a used Labophot you need to be sure the fine focus works smoothly. There is a plastic pinion gear on the fine focus shaft that is prone to cracking if the lube has dried out and the knob "forced". My understanding is that Nikon does not offer the part any longer. Although I have seen custom made metal ones. (I've often wondered if that particular gear was make this way on purpose so as to be "sacrificial" to prevent damage to the metal gear-train). If the scope is lubed adequately it's not really a problem, and it's an excellent focus mechanism. (Olympus, and perhaps others, also have a plastic gear, but it seems to be less commonly a problem).

If you haven't seen it already check out NikonUsers hacked BHM here:
http://www.photomacrography.net/forum/viewtopic.php?t=6070&postdays=0&postorder=asc&start=15
If you really get a good deal on a stripped down stand this approach is an option.

You might also keep an eye out for the Olympus CH stands. They were the series "below" the BH, but they have a nice coarse/fine focus mechanism. (Calibrated at 2.5 micron per "tick").
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Choronzon



Joined: 21 Feb 2010
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Location: Chicago USA

PostPosted: Sun Mar 07, 2010 7:25 am    Post subject: Reply with quote

Enrico,
If I was pursuing this direction, I would look for a stand that allowed the stage carrier to be lowered or raised on a dovetail, to allow much thicker specimens than microscope slides. Such stands would be a Nikon Optiphot 1 or 2, Leitz Ortholux 2, or Leitz Orthoplan. Also the Olympus BH2, I believe, has this capability. All of them have the "infinate" fine focus, as opposed to fine focus knob stops. I would stay away from the Galen stand, as in my opinion, it's one of the worst stands ever made of the era. If cost is an issue, I would go with an Optiphot 1, also it would be fairly easy to motorize. Be aware, however, that when you motorize one of these Japanese stands with plastic fine focus shaft gearing, that the lifetime becomes shortened. Yes, the Olympus also have plastic fine shaft gears, I think I still have one or two rolling around in the bottom of my tool kit.
Also, there was, back in the day, a Nikon stand, called the Optiphot M, without any transmitted light capability. It had the stage lowering dovetail, and removeable nosepiece. These should be cheap by now, and may be just the ticket. I personally have both an Orthoplan, and Ortholux 2, my favorite Leitz stands.
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enricosavazzi



Joined: 21 Nov 2009
Posts: 1212
Location: Borgholm, Sweden

PostPosted: Mon Mar 08, 2010 1:41 pm    Post subject: Reply with quote

Charles Krebs wrote:
Enrico,

I have no familiarity with the Leitz stands you are talking about. But have pretty significant experience with the Nikon Labophots
...
If buying a used Labophot you need to be sure the fine focus works smoothly. There is a plastic pinion gear on the fine focus shaft that is prone to cracking if the lube has dried out and the knob "forced". My understanding is that Nikon does not offer the part any longer. Although I have seen custom made metal ones.



Thanks Charles. I do happen to have a Nikon rack similar to the ones used in the Labophot, but just the rack (old type with small fine focus knob, it did come with a right-angle bracket with head and nosepiece bayonets that I removed, and attached a quick-release plate and socket; see picture). This rack catches slightly, but noticeably, at one specific position of the fine focus knob. I would like to disassemble it to see if it is a cracked gear or a piece of crud in the gears, but I cannot see an obvious way. Do you have any information?

I have been looking for Labophot and Olympus stands on eBay, but it seems that most have trouble with the focus mechanism (either explicitly mentioned or "between the lines"). Nothing I would feel confident to buy, or the price is too high. Depending on price and on how the Labophot rack is made internally (number of gears etc.) I might try to buy a beat-up Labophot stand for parts and either fix my present focusing rack or use its parts to fix the stand. If there is only one gear of the type that usually breaks in a rack, however, this is not a safe bet, and I might end up with two racks, both with the same broken gear.

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Charles Krebs



Joined: 01 Aug 2006
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Location: Issaquah, WA USA

PostPosted: Mon Mar 08, 2010 2:57 pm    Post subject: Reply with quote

Enrico,
Quote:
This rack catches slightly, but noticeably, at one specific position of the fine focus knob

Obviously I don't know what the problem is, but....

I've experienced this with Labophots. On disassembly this plastic pinion gear (which is attached to the fine focus shaft that runs through to both sides) was found to be cracked, but still held firm to the shaft. As a result the fine focus would still work, but there was a slight "catch" when the section with the crack came around and meshed with the next gear.

It's been some years since I disassembled a Labophot, so I'm a little "foggy" ( Wink ) as to the exact procedure (it's all sort of run together with 3 or 4 other models I've disassembled since). As I remember, removing the fine focus shaft was pretty simple (very little to take apart, and you don't get into the coarse focus or the other gearing at all), and you can't get into much trouble. I don't know if your focus block will be the same, but on my Labophot stands there is a single set screw on each of the fine focus knobs. I'm pretty sure this removed the knobs (if not, check for end caps and remove them to reveal any locking collars or nuts. I think it will be pretty obvious one the knobs are removed. The shaft, with attached gear will pull out from the side that has the additional gearing. I should mention that my experience is with the Labophot I (the Optophot models also used the same part). The Labophot II changed the shaft design, but I would be surprised if it were not a simple procedure as well.

If this is the problem you could double check with Nikon. The part came as the shaft with the gear attached. As I mentioned, I seem to recall hearing that they were no longer available, but I never actually checked myself. (Nikon is pretty good about dealing with individuals for parts). If this is the issue and it is not available and you with to pursue a repair I might be able to locate the source for the custom made metal replacement. (I saw it some time ago, and it was not cheap then... seem to remember about $80).

Note added.... I just checked and found the metal replacement... now $120...OUCH!
http://www.microscopesolutions.com/component/page,shop.product_details/category_id,24/flypage,shop.flypage/product_id,39/option,com_virtuemart/Itemid,32/vmcchk,1/

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RogelioMoreno



Joined: 20 Nov 2009
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PostPosted: Mon Mar 08, 2010 4:54 pm    Post subject: Reply with quote

Charles Krebs wrote:


Note added.... I just checked and found the metal replacement... now $120...OUCH!
http://www.microscopesolutions.com/component/page,shop.product_details/category_id,24/flypage,shop.flypage/product_id,39/option,com_virtuemart/Itemid,32/vmcchk,1/[/size]


I replaced my fine focus shaft and that was the only one that I could find. It is all made of metal, there should not be any future problem (I hope).

To remove the fine focus shaft:
1. Remove both fine focus knobs by loosing the hex screw that keep them in place.
2. On the side that has the numeric scale, remove the metal ring that cover the coarse knob using a small screwdriver, insert the screwdriver inside the small half-circle that you will find at the edge of the ring that cover the corse knob.
3. Remove the 3 screw that keep the coarse knob in place and remove the coarse knob.
4. Now you can see the gear of the fine focus shaft, pull the shaft to remove it.

Rogelio
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enricosavazzi



Joined: 21 Nov 2009
Posts: 1212
Location: Borgholm, Sweden

PostPosted: Mon Mar 08, 2010 11:48 pm    Post subject: Reply with quote

RogelioMoreno wrote:


I replaced my fine focus shaft and that was the only one that I could find. It is all made of metal, there should not be any future problem (I hope).

To remove the fine focus shaft:
1. Remove both fine focus knobs by loosing the hex screw that keep them in place.
2. On the side that has the numeric scale, remove the metal ring that cover the coarse knob using a small screwdriver, insert the screwdriver inside the small half-circle that you will find at the edge of the ring that cover the corse knob.
3. Remove the 3 screw that keep the coarse knob in place and remove the coarse knob.
4. Now you can see the gear of the fine focus shaft, pull the shaft to remove it.

Rogelio


Thanks Rogelio, the rack disassembles as you say. I am going to order one, or maybe two, of the replacement shafts while they are still available (it might be good to have a spare for a future stand/rack purchase).

In my case the plastic gear is not cracked but visibly worn. The shaft was also accidentally bent then straightened, so it is a good idea to change it anyway.
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RogelioMoreno



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PostPosted: Tue Mar 09, 2010 4:59 am    Post subject: Reply with quote

enricosavazzi wrote:

Thanks Rogelio, the rack disassembles as you say. I am going to order one, or maybe two, of the replacement shafts while they are still available (it might be good to have a spare for a future stand/rack purchase).

In my case the plastic gear is not cracked but visibly worn. The shaft was also accidentally bent then straightened, so it is a good idea to change it anyway.


Enrico, now that the fine focus was removed, check the grease to no be sticky.

Rogelio
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enricosavazzi



Joined: 21 Nov 2009
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Location: Borgholm, Sweden

PostPosted: Tue Mar 23, 2010 8:25 am    Post subject: Update: Leica Galen III stand Reply with quote

As an update, I bought a Leica Galen III stand, despite the recommendation to the contrary by Choronzon (above). The reason that made me decide is that the fine focusing mechanism is of the infinite type with planetary gears, just like the Nikon and Olympus ones often discussed in this forum, with a large scale apparently graduated in 100 ticks and 200 µm per turn. The total travel is 30 mm (of which the top 10-12 mm can be blocked by a variable stop, to prevent a collision between objectives and cover glass). The specimen stage is quite usable, the 1.25 NA condenser a bit oversimplified.

The Galen stand is indeed poor in a few respects, like fixed nosepiece for only four objectives, nylon rack of the condenser focuser and non-centerable critical illuminator (Herr Köhler must be turning in his grave). I would not use nor recommend it for serious microscopy. It may have been designed mainly as a student microscope, but it is quoted surprisingly often in the "Materials and methods" section of biomedical papers.

The coarse/fine focus mechanism seems fine, but I might investigate a slight tendency of the fine focus knob to rotate when the stage is under load - apparently not enough friction, so some adjustment might be needed [Edit: actually, it seems I had overtightened the friction control of the coarse focus. When undone, the coarse focus knob feels unusually "soft", but the fine focus knob stays put]. The slider that carries the stage/condenser rides on ball bearings and was quite wobbly. Someone without a clue had attempted (and failed) to fix it, but it was a 5 minutes job to bring it back to specs. Other than this, the stand seems to have been used extremely little, with none of the usual nicks, dings and wear. Perhaps it developed the wobble shortly after its purchase and was simply stripped of optical parts and put in storage.


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enricosavazzi



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PostPosted: Thu May 13, 2010 3:09 am    Post subject: Olympus CH stand Reply with quote

One more update - I got a complete Olympus CH microscope at about half the price I paid for the Leica Galen stand I discussed above, and could not resist the offer. Here are my impressions.

Like the Leica Galen, this is not a stand I would recommend for microscopy. The illuminator and condenser are oversimplified, with practically no adjustments (not even a condenser rack, although the condenser has a plastic helicoid sleeve).

The interesting thing is of course the fine focusing mechanism with planetary gears, which, like in the Galen, Nikon, Olympus BH and other stands discussed in this bulletin board, allows the whole range of movement of the rack. As usual, the fine focus scale is graduated in 100 ticks and 200 µm per turn. I would rank this stand as worse than the Leica Galen, for the following reasons:
- Shorter range of focus movement (slightly more than 20 mm, compared to the usual 30 mm).
- "Feel" of the focus controls is slightly rougher.
- Fine focus scale difficult to see (moulded in black plastic, not painted white).
- Edge of the objective revolver is not knurled, which forces one to change objectives by pushing or pulling the latter.
- One gear of the stage micrometer is fully exposed, and is easy to touch accidentally.

In spite of these problems, this stand is quite usable for manual stacking (albeit with a more restricted choice of lenses, because of the reduced focus movement) and is potentially modifiable for automatic stacking.


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rjlittlefield
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PostPosted: Fri May 14, 2010 1:52 am    Post subject: Re: Olympus CH stand Reply with quote

It is interesting to see what range of capabilities there are in a single "model" from one manufacturer.

I have an Olympus CH base also, but it differs from Enrico's in every point that he mentions:
- condenser rack present
- 30 mm of focus movement
- fine focus scale painted white
- edge of objective revolver is knurled
- no exposed gears on stage positioner

The design of mine appears "older" than Enrico's, more angular and rugged somehow. See HERE for illustration.

--Rik
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enricosavazzi



Joined: 21 Nov 2009
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PostPosted: Tue May 18, 2010 11:28 am    Post subject: Reply with quote

As a third review of a focusing rack, here are my impressions of an Olympus BX30MF. This is not a complete stand, but what one could call a "focusing rack on a stick" plus nosepiece. It has a built-in revolving nosepiece of generous size, with space for five RMS objectives. The right-angle bracket on which the nosepiece is mounted is an integral part of the sliding mechanism and cannot be separated from the focuser. On the top side of the bracket is a female conical bayonet that seems to fit well a Zeiss 43.5 mm bayonet (the most common Zeiss size). This makes it easy to find a physically compatible microscope tube or head. The column hole in the mount accepts a 32 mm (1 1/4") round column, which can be found as stock metal (of course a fitting stand will be my next project). There may well be ready-made stands for stereomicroscopes with a column of this size. The particular interest of a column-mounted focuser is that it allows the distance from the baseplate or stage to be increased arbitrarily, thus allowing the use of lenses with any useful focal length and working distance.

There is a fair amount of play of the slide when pushing it upwards, which is taken up by the weight of the slide. It is irrelevant with the focuser mounted vertically as designed to be used, but if you need to mount the focuser horizontally, you need to spring-load it. It appears that Olympus makes, or made, a spring-loaded mechanism to counterbalance the weight of heavy microscope parts mounted atop the moving platform (the weight of microscope camera, head and axial/fluorescence illuminator can add up quickly). This mechanism attaches to two threaded holes at the top of the mount. Probably it will not be necessary to add a counterweight mechanism for the limited weight of a DSLR and extension tubes or bellows. This probably means that the mechanical slide and the focuser mechanism are overspecified for my use (which is only good).

It is a simple matter to remove the revolver (via three screws), and feasible to mount a stage in its place, if desired. The bayonet mount for the microscope head could be used for this purpose. I believe I will keep the revolver, since I already have stands with focusers connected to the stage.

The coarse and fine movement of the rack is 30 mm. As usual, the fine focusing knob is graduated in 100 ticks and 200 µm per turn. The rack is quite wider than the one of an Olympus CH stand. It might or might not be similar to the one of BH stands. The knobs of the fine focuser are covered with easily removable, press-fit rubber handles that increase the diameter and make focusing more precise. The "feel" of the focuser is very smooth, a great improvement over the one of the Olympus CH stand mentioned above and quite better than the Nikon Labophot rack and Leica Galen III stand. The knurled rim of the objective revolver is also very comfortable to operate. I believe the BX30 components were made mainly for assembling custom-configured industrial microscopes.

I hope this will be my last review of a fine focuser or microscope stand for a while - I believe I now have enough of them to permanently mount all of my most useful RMS lenses. Albeit, interesting stuff seems to be auctioned in clusters, so one never knows...
Incidentally, there is a microscope advertised right now as eBay item 250603126141 that uses the same focusing block (I have no connection to the seller).


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