Pocket microscope

phil m · Post by **phil m** » Sun Apr 26, 2015 1:43 pm

Bausch & Lomb made very durable little Brinell microscope at one time. They often show up on ebay, sometimes for very little. They can rest on a flat cast base about 2 inches in diameter with a hole in the centre. The optical tube focuses by push pull in a cast collar, which is adjustable for tension and smoothness. There is a moveable locating ring on the optical tube, so it can be adjusted so as to bring the objective into focus precisely at the surface of the base, so anything it is put on is in focus. It accepts 160mm R.M.S. Optics,top and bottom. They come with a 3.5 X .10 N.A objective and a 10X huygens eyepiece but I have used B&L 10X widefield in one , which gave a fairly flat image. A B&L 10X Planoscopic would give an even flatter image but with a narrower field.

The instrument has 45 degree mirror surrounding the objective, facing down, so turning the mirror towards a source of brightness gives a pretty well illuminated incident image. The base also has a convex circumferential reflector surface,of glossy white enamel on the upper surface of the cast base, facing upward, so there is some facility to use this with an external light source for transmitted illumination. It is very easy to fashion a small live box to fit into the objective well, so live specimens can be viewed by placing the microscope over a light source. A modern battery operated flat disc light would be ideal for that.

It is about 8 inches long and is a true pocket microscope. They originally came in a little wooden case about 9X3X3.

There was a thinner and slightly longer portable microscope version that came in a little leather case with a folding snap top. It had the same optics but of fixed focus, with the lower surface at a mirrored 45degree angle. Placing the end of the microscope near to the subject/object, resting on the same plane , gave an incident illuminated 35X image. Presumably it could be used over a backlit slide as well. Here is a picture of one, in its case:

Here is a picture of one, along with one equipped to receive a hardness tester and remote incident illuminator, as well as some other older pocket microscopes:

AdminCS edited formatting.

Chris S. · Post by **Chris S.** » Sun Apr 26, 2015 11:26 pm

pwnell wrote:As another example, my MP-E 65 lens at 5:1 can resolve different diatoms, small flatworms - even the zooxanthellae in the flatworms, zoothamnium etc. when zoomed in on a simple 18MP FF sensor. That kind of resolution is a great start. Going up to twice that and perhaps adding darkfield / polarization would be candy on top - as seeing vorticella / rotifers etc in BF is hard.

Waldo, if I had your requirements, I think I'd assemble the needed optics myself. Doing so doesn't seem difficult. After pondering your situation for a few days, what took shape in my mind's eye is similar to what Phil M posted about simple, vintage instruments. Phil's post has merit, but if I were in need of such a device, I'd prefer using hardware I assembled myself. This is because I could then modify it--very easily--as needed. Comparatively, a vintage, off-the-shelf, assemblage, could not be so easily modified.

What you're looking for seems easy enough. Start with a high quality finite objective and eyepiece, and put a tube of air between them.

Suppose you take a good 10x finite objective, such as the Nikon 10x/0.30 N Plan (nominal tube length 160mm, 10mm of which was allocated for the eyepiece), and stick it on a 150mm tube. Then place an eyepiece on the opposite end. Voila, instant microscope.

OK, you'd want to add a few frills. One frill would be a slide-holding attachment in front of the lens--simple enough. Another frill would be some means of focusing--also rather simple, though multiple approaches exist (you could adjust the distance between objective and subject, or adjust the distance between objective and eyepiece). You would want to flock the inside of this assemblage to avoid light refelecting within it and causing veiling flare. And since you want darkfield and polarization, you would need to add a few more frills. I'd see these as slightly more involved, but not all that difficult. A bigger frill would be an x/y slide movement to let you scan the across and up/down the slide; this could be done fairly easily, but would make the unit less pocketable.

I haven't completely thought through the design, but did look up a few potential components that I'll list here. These will be Edmund Optics C-mount components. Conversely, Thorlabs 1-inch tube components might do the job as well or better, and at a lower price, but I haven't looked them up for this use.

For the tube, consider Edmund Optics C-Mount Extension Tubes.

For the eyepiece holder, consider Edmund Optics Techspec C-Mount Microscope Eyepiece Mount.

For a spendy, but likely wonderful, focusing helicoid, consider the Edmund Optics Helicoid Barrel Accessory.

75RR · Post by **75RR** » Wed Apr 29, 2015 6:03 pm

I picked up a Walter Uhl Rod Microscope SM second hand locally a month or so ago.
Unfortunately I have not been able to find out what it costs in the shops.

It has a removable glass base to help flatten cloth and paper (printing and thread count).
Once removed one can view 3D objects or slides. (It is focusable)

Ocular is a standard 23mm - objective has a standard RMS thread. So one can swop them out.
It came with a 15x ocular and a 7x objective. That = 105x which was a little too much for me.
Put in an 8x ocular and a 3.2x objective, for a more usable 25x.
Have since then put the 7x objective back in giving 56x.
Ocular is held by a very small grub screw so it is more practical in the field to swop the objectives. Nice build quality as well.

If you like I can dismantle it and take photos so you can see how it is put together.

http://www.walteruhl.com/rokdownloads/D ... e%20SM.pdf

zzffnn · Post by **zzffnn** » Wed Apr 29, 2015 6:49 pm

The type of scope mentioned by 75RR has many versions on the market. They may even work with 10x-20x objectives, when you use a flat battery-powered LED light with diffusion at the bottom. This light may work: http://www.amazon.com/Fulcrum-30010-301 ... B000R7PM36

Better high eye point aftermarket eyepieces will also help, as portable scopes' eyepieces are usually pretty bad.

75RR · Post by **75RR** » Thu Apr 30, 2015 5:23 am

Just a quick heads up on adapting Rod Microscopes (well mine anyway)
The UHL objective is 15mm long.(Not counting threads)
Working distance is 14mm
While a 10x and a 25x will fit and the microscope can be focused, it is at the very top of its movement. If one turns it a little more it dismantles.
This is especially true of the 25x, making the the 10x at 38mm the maximum practical objective length.
At the other end of the range the larger objectives protrude beyond the stand, making the designed "stop" ineffective.
This is a concern as the objective is then unprotected.

The 3,2x objective I used is effectively the same size as the UHL 7x
The spiral focusing method works very well.
It is quick, smooth and maintains focus.

Note that in this image the microscope is focused on the paper it is on.

pwnell · Post by **pwnell** » Thu Apr 30, 2015 9:12 am

Guys - thanks so much for this information - I have seen the posts, will read them as soon as my work allows me to take a breath. Very excited to see all the possibilities.

Unfortunately I have all infinity objectives so I might need to look for some 160mm finite optics on ebay or somewhere...

zzffnn · Post by **zzffnn** » Thu May 28, 2015 2:42 pm

Waldo and anyone who is interested in pocket microscopes:

After some field testing, I would recommend trying the Meade Rediview pocket microscope (with 80x and 160x magnification and transmitted LED light). I bought a used one off eBay for $16.49 shipped and will buy a 2nd one in an eye blink if I see one for that price again. Currently, you have to pay $40 shipped for one of those. I won't buy a 2nd at that price, but if I don't have the 1st one and knowing the images I am getting, I would be willing to pay $40 for it.

Image quality (when viewed with eyes) is similar to the following photo (taken off a Chinese full-sized scope w/o condenser at 100x with cell phone), with 80x being better and 160x being similar:
http://www.photomacrography.net/forum/u ... hone_2.jpg

You should be able to tell Rotifer from Vorticella using this pocket microscope.

I have tried Klaus Kemp test plate too. Stock (integrated) LED light is weak and just enough for straight bright field. But you can use a small Cree LED flashlight instead and get darkfield or oblique. You will have to use a pocket tripod to hold the flashlight or microscope though.

Mechanics (slide holder and focusing) worked just fine for me at 80x or 160x. The scope has a tripod hole at the bottom. But I usually just hand-hold it.

The view field and eye point height is quite decent, even when I wore my strong prescription eye glasses (and I have astigmatism and always use wide field high eyepoint eyepieces).

The Amazon pocket scope that I mentioned before did not work in the field. Simply not enough light, as it is reflected (not transmitted) ight and working distance is too short.

I suspect 75RR's pocket scope requires a strong Cree flashlight as well, as it uses reflected light (which is less efficient than transmitted light when viewing pond life).

pwnell · Post by **pwnell** » Thu May 28, 2015 10:51 pm

Like this one? http://r.ebay.com/TySEfl

zzffnn · Post by **zzffnn** » Fri May 29, 2015 5:04 am

pwnell wrote:Like this one? http://r.ebay.com/TySEfl

Yes. It is similar to that Trekker pocket microscope described by Mic-UK: http://www.microscopy-uk.org.uk/mag/ind ... ekker.html

except that Meade Rediview offers higher magnification that is useful for pond life:

yvan_be · Post by **yvan_be** » Mon Nov 09, 2015 4:14 am

I used and still use a Zenit/LOMO SHM-1 or an YWM-1 as a pocket microscope. Well, more of a backpack microscope...
Those were sold at the time as a toy microscope, but they're equipped with decent 8x/0.20 and 20x/0.40 LOMO achromats and 7x, 10x and 15x Huyghian eyepieces.
These are offered for sale on ebay every once in a while for next to nothing.

See: http://www.microscopy-uk.org.uk/mag/ind ... -Lomo.html for some pictures and specifications.

zzffnn · Post by **zzffnn** » Sat Jan 16, 2016 12:10 pm

If Waldo or anyone is still looking for such a pocket scope (of up to 450x), here is one that costs about $43-$49 shipped to continental USA.

David Walker did a review of it 11 years ago:
http://www.microscopy-uk.org.uk/mag/art ... micro.html

In the following thread of mine, you would see sample photos it produced using Klaus Kemp test diatoms and an afocal camera:
http://www.microbehunter.com/microscopy ... =16&t=2246

The seller happens to live in my city and he still has >= 17 units to get rid of. We bought off 3 units from him. Seller used to sell such units at $75 each, but now he lost interest in them and just wants to get rid of his stock.

Considering the low cost, I like it for pocket use.

Interested individuals can contact the seller directly at:
bikash.ghosh at sbcglobal dot net

Edit: Here is seller's direct eBay listing with "Buy It Now" for $47 and free shipping within continental USA:

http://www.ebay.com/itm/micro-microscop ... 1830741617

I don't know if he can ship small quantities internationally to outside of USA. I am guessing he may not, since there is minimal (if any) profit.