Objectives for epi illumination - an advice need

Marek Mis · Post by **Marek Mis** » Sun Apr 13, 2014 12:47 pm

Hello,

I am going to buy some good quality objectives (20X and 40X) for epi illumination (for example employing IKEA jansjo lamps) with long working distances, which do not need the cover slip.
I have the BH-2 Olympus microscope. Could anybody suggest any such objectives for me ? I would like good quality for the resonable price

Marek

ChrisR · Post by **ChrisR** » Sun Apr 13, 2014 3:56 pm

Are you using an EPI lighting component without the illuminator it's designed for?

Finite or infinite?

Chris S. · Post by **Chris S.** » Sun Apr 13, 2014 8:12 pm

My sense, reading Marek's query, is that he wants to use reflected light from sources placed near the subject, rather than use a coaxial episcopic illuminator.

If so, he would want objectives with long enough working distance to permit this sort of lighting.

Olympusman · Post by **Olympusman** » Tue Apr 15, 2014 7:55 am

Marek,
You might have a hard time getting light under the objective with those lamps. I use a two lamp gooseneck fiber optic unit but as had been noted working distances under the objectives can be limited. The best I can do is with my 4x and 10x objectives. 20x and higher I can't get any light under the objective to speak of.

Marek Mis · Post by **Marek Mis** » Sat Apr 19, 2014 10:27 pm

Thank you for your advices.
I am looking for some good quality long working distance objectives which are enough far away off the specimen. I know that some members of this forum use such objectives but I do not remember who it is.

I do not have any epi illuminator. I would like to use two or three Jansjo (IKEA) lamps. I simply need 20 X or 40 X extra long working distance objectives and I need some advice which of them are the best.

Somewhen I even managed to take the photomicrograph in epi illumination (consisting of two small LED pocket torchs) with my Olympus 20 X Splan Apo. But the quality of that image was not enough good. I am enclosing this image below.

Polllen grains

Marek

rjlittlefield · Post by **rjlittlefield** » Sun Apr 20, 2014 12:22 am

Marek Mis wrote:But the quality of that image was not enough good. I am enclosing this image below.

This image looks quite good to me. What about it bothers you? What would you like to have better?

--Rik

ChrisR · Post by **ChrisR** » Sun Apr 20, 2014 3:56 am

I simply need 20 X or 40 X extra long working distance objectives

The obvious first choices would be Mitutoyo then, for best, which are somewhat better and more expensive than Nikon ELWD Plan objectives, which also have shorter working distances.

Mitutoyos also come in SLWD versions, which have inferior NAs. It depends how much WD you need.
I've noticed some Olympus objectives with long working distances but know nothing of them.

Planapo · Post by **Planapo** » Sun Apr 20, 2014 10:34 am

Mitutoyo... Nikon...

Hmm...

if Marek wants to use his BH-2 Oly microscope and the matching Oly corrective eyepieces and corrective projectives (photo eyepieces) then with the already fully corrected Mitutoyos or Nikons aberrations will be re-introduced.

--Betty

ChrisR · Post by **ChrisR** » Sun Apr 20, 2014 12:36 pm

if Marek wants to use his BH-2 Oly microscope

Indeed Betty,

I was hung up on forum users' typical, more haphazard approach, with random hardware.
There would be ways to use some of the Nikon finites (assuming it's a finite BH2) with some other eyepiece, but the Mitutoyos would be more of a challenge.

Charles Krebs · Post by **Charles Krebs** » Mon Apr 21, 2014 11:13 pm

Marek,

I am amazed that you got that image with the 20X S Plan Apo. Its working distance is only 0.55mm, and the results without a cover slip have always looked soft to me.. this certainly does not.

Prior to the BH series Olympus made some M Plan objectives that I believe were finite type, but I don't know anything about them. If you look at some of the older brochures on Alan's site you might find some info:
http://www.alanwood.net/photography/oly ... loads.html

The "M" type objectives that were made for the BH series microscopes were the "LBM Infinity Corrected Optics". These required a 180mm tube lens that was built into the various vertical illuminators that Olympus made for the BH microscopes series. These also used the corrective eyepieces and NFK photoeyepieces. Are you currently set up with NFK photoeyepieces on your BH trinocular tube?

There was a 10/0.30 M S Plan with a 9mm working distance. a 20/0.46mm with a 3mm working distance, and a LWD 20/0.40 with a 7mm working distance. There was no 40X, but a LWD 50/0.60 with a 3mm working distance. (There were quite a few different objectives in this series but these are probably the most interesting for your use). Sometimes you can find one of the vertical illuminators pretty cheaply, especially if all you are really after is the tube lens part. The objectives in this series are pretty common on the used market.

The newer "M" type Olympus objectives (for BX series microscopes) also use a 180mm tube lens, but they no longer use the corrective eyepieces, as all chromatic corrections are made in the objective. Both of these series have RMS threads and are 45mm parfocal. So they would fit into a BH nosepiece and focus at the "right" distance.

Another option would be finite type "M" objectives like the Nikon M Plans that many use on bellows. They don't need a tube lens, but you would need to somehow raise your viewing head an additional 50mm since their tube length is 210mm. They should not be used with corrective photoeyepieces.

Marek Mis · Post by **Marek Mis** » Wed Apr 23, 2014 2:35 am

Thank you all for the advices.

Rik,
OK, this image is relatively good. But the main problem was the way of lighting it. It was extremaly difficult and unconvenient just because of very short working distance. Apart from this the possibilties of stacking are very limited.

Charlie,
Thank you very much for your exhaustive explanation.
Yes, I use NFK 2,5 photoeyepiece
I know about possibility of buying the vertical illuminator, but it is quite expensive. I wanted to use some appropriate objectives without any additional equipment.
As I understand all of these older "M" Olympus objectives are designed to be cooperating with the longer tubes and tube lenses.
So the vertical illuminator should be the best solution for me ...
Did you take any photomicrographs using such illuminator ? I am very wonder how they look like. I am afraid the lighting of the subjects is quite flat, without the shadows, what can make them slightly artificial.
If you took such photographs will you be so kind as to enclose any example ? It will give me the answer if it is worth of buing it.

Marek

Charles Krebs · Post by **Charles Krebs** » Wed Apr 23, 2014 11:32 am

Marek,

Did you take any photomicrographs using such illuminator ? I am very wonder how they look like. I am afraid the lighting of the subjects is quite flat, without the shadows, what can make them slightly artificial.

I've posted a fair number of images using an epi-illuminator, (both brightfield and darkfield). Often the darkfield epi was the better, and it was always necessary to use polarizers with the brightfield epi to reduce flare. Naturally I only posted ones that I felt worked pretty well with this type of light. There were quite a few cases where the lighting was not that exciting and didn't work well. For magnifications where you can get objectives that offer sufficient working distances to light "externally" you can get more dramatic and in many cases better light. (That is one reason I put together the MM-11. With that I can work comfortably up to 50X (on sensor) with direct projection, and usually establish more attractive lighting than would be provided by an epi-illuminator. But with high power objectives like a 100X that almost always have miniscule working distances, epi-illuminators can be useful).

The reason I mentioned possibly getting a vertical illuminator was basically to get access to the section with the tube lens. A BH2-UMA in good shape is expensive, but there were several other older models that incorporated the 180mm tube lens (offhand I don't recall the model names but it is not hard to find out what they were). It is not uncommon to find ones where the tubular "extension" that provides for the epi-illumination is broken (sometimes completely off!) or is missing key parts, but the basic section of the body that has the 180mm tube lens is in good shape. (I've seen such pieces go for around $100 or even less). If you will be lighting externally that is all you really need to make use of the Olympus "LBM Infinity Corrected Optics" that were made for the BH series. Since you are already set up with the NFK photoeyepiece, this seems to me to be a good option since you already have the proper corrective eyepieces for this series of objectives. As mentioned earlier they are RMS threaded and 45mm parfocal. They are quite plentiful on the used market, and with a little patience can usually be had quite reasonable prices.

If you took such photographs will you be so kind as to enclose any example ? It will give me the answer if it is worth of buing it.

Marek Mis · Post by **Marek Mis** » Sat Apr 26, 2014 9:27 pm

Charlie,

Thanks a lot for your help ! You gave me a plenty of links which will help me to take decision.
These images taken with illuminator are beautiful ! Especially in dark field.
But tell me additionally, do you mostly use the halogen lamp with this illuminator or external fiber illumination ? I am asking you about it because I could read in one of your comments that you used the fiber illumination.

Thank you once again

Marek

Objectives for epi illumination - an advice need

Objectives for epi illumination - an advice need

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