MicrobeHunter.com Microscopy Forum

At 1000x magnification, with the aperture of the condenser at its smallest, there is not enough light, the image is to dark. I have to open the aperture a bit. Opening to much reduces contrast. (I use a 30W light bulb, at least that's what I think is installed) Based on this, it seems like you begi...

If you print concentric circles on a sheet of acetate and put it in the filter tray you can use a phase telescope to look at it at the back focal plane (with the correct objective in place) and see how large the rings need to be.

I have the non-phase version of the Fluor 40x 0.85 with correction collar. I also have the 10x and 20x Fluor CF objectives from the same series. Unfortunately, I cannot compare them to the Plan Fluor objectives as I have never used any of those. The Plan Fluor were some of the last objectives Nikon ...

The condenser caps have been printed, painted flat black with enamel paint, and the half-ball lenses have been glued in place with transparent silicone glue. I will be trying them out soon, but I first need to deal with some other issues. First, I need to clean up a little silicone that ended up on ...

Also described on P60 in the more detailed instruction book, scanned here:
http://www.microscopy-uk.org.uk/mag/art ... n-book.pdf

Thanks for your input! With your helpful nudge, I actually think that I managed to find it myself. I think this objective was made for the Leitz Panphot polarizing microscope. Here's the scanned manual: http://www.science-info.net/docs/leitz/Panphot-6-57.pdf On Page 13, it lists a Coated fluorite oi...

This funny little objective popped up in my eBay searches: https://www.ebay.com/itm/164084835993 https://i.ebayimg.com/images/g/GokAAOSw0vZcYJSL/s-l1600.jpg It's an extremely short-nosed little Leitz 80x Fl (Fluorite?) oil objective with a 1.30 NA intended for a 215mm tube length and no cover slip. ...

If you would like to distribute a few as a standard target and compare microscopes, I would be happy to put one under a Wild M3 and an M7S, take some pictures and add them to a thread. I think that's a great idea! Agreed ... A super test-piece for distribution [ 250 near identical items ] I’m in En...

Whether your condenser performs adequately dry in the .70-1.00 N.A. corridor, should be fairly easy to determine during use. You have the up to .70 version without the immersion cap and the oil immersion version with cap at whatever N.A. it ends up at as comparisons, that is presuming you have an o...

Btw, I just sent the .STL files for a new 39.5mm condenser sleeve adapter + oil caps (11.12mm and 12mm) to the SLS printer at work. They've been rather slow to respond, so I'm not sure how long it'll take. https://i.imgur.com/dMQzmNI.jpg The "snap-on" fit of the 39.5mm adapter sleeve is a little exp...

Item 8 in the ‘Directions for Use’ seems quite explicit about usage of the immersion cap: http://microscope.database.free.fr/Accessories_manuals_files/51-21%20Phase%20contrast%20equipment%20with%20the%20Heine%20condenser.pdf MichaelG. Thanks, I actually haven't looked at that for a while. What exac...

By the way, here are the two lenses I bought if anyone is interested:
https://www.aliexpress.com/item/32902662159.html
https://www.aliexpress.com/item/32973679058.html

I recieved the two BK7 hemispherical lenses yesterday and I've done some quick experiments. They were quite promising! I first tried to simply place a lens inside the "bowl" of the lower unit and using the condenser dry (didn't want to risk getting oil in the condenser). This, however, resulted in a...

Thanks a ton for your input, Phil! Reading your post and the AO patent has gotten me a lot further to understanding what is going on. The left hand image is only a partial representation. If a close look is taken, the the upper plano/convex lens is only allowed to settle into the well below, as far ...

With these kind of hemispheric top lenses, you have to consider "how thick" your slide glass will be. Note the tight tolerances for oil DF condensers. BR, John Thanks for the input, John. Do you have a grasp of what aspects of the hemispheric lens that will determine if the top lens will fit a stan...

Very interesting document, I'll have closer read when I find time. I think we have the same version of the patent. There is clearly a slight discrepancy between Fig. 1a and Fig. 3. The lens in 3a looks very much like a half sphere, whereas the one in Figure 3 has been ground down ~0.5 mm or so. Its ...

if the lens turn out to be mounted slightly at an angle. Perhaps you can assemble it upside down so the barrel front and the lens rest on a piece of plastic foil on a piece of flat glass. I suspect that the original centring/levelling method might have been to spin the assembly in the lathe, and us...

Lakeside No. 70C is a remarkable [and ‘reassuringly expensive’] cement, widely used when preparing thin petrographic sections. ... It may be very suitable for this job. http://www.lakeside-products.com/html/cement.html Regrettably; although its properties are well described, I have never found its ...

In my quest to better understand the optical behaviour of hemispheric lenses and their relationship to NA, I stumbled upon this recent paper that provides a systematic overview of microscope objective designs. The authors put together a large database on patented objective designs and classified the...

Hi Victor, that is an interesting project! Pete's hint with the porosity is good, you should fill the pores before use. Epoxy glue becomes failry fluid when warmed a bit an woulp probably soak into the pores well. Silicone doesn't have much glueing force so I would choose something else to take up ...

Thanks, PeteM. I'm thinking it might be wise to use one adhesive to keep the glass in place, and another to seal the gap. Maybe enamel paint for the seal. Or Shellac? I don't plan to clean it with Xylene so that should be OK. I had a little closer look at the patent, and in Figure 1A the top lens lo...

Neat arrangement! I had a look at the original paper. I am toying with the idea of building my own LED-based EPI fluorescence illuminator. One of the problems I've faced when designing a fully Köhler capable illuminator is that it quickly becomes rather long and large. This link gave me the idea tha...

I have a Leitz Heine, but no oil cap. After looking in vain for an affordable oil cap, I've started thinking about making my own. I've studied the patent a bit, and the oil cap simply looks like a hemispheric (half ball) lens that fits into the concave surface of the upper lens: https://i.imgur.com/...

abednego1995 wrote: ↑

Mon Jan 27, 2020 2:30 am

Viktor, thank you for the Paolo Pozzi reference. I had some difficulty in determining objective BFPs on my bench so this method is excellent.

BR,
John

Glad I could give something back, your input has been exceedingly helpful to me.

Regarding the case where there is single objective-side prism, but multiple condenser prisms, we discussed this in the photomacrography.net thread as well: https://www.photomacrography.net/forum/viewtopic.php?t=38955&highlight= In it, Ichty wrote: The single [objective-side] prism is designed to mat...

Another thing. In abednego's post above, note the formula: http://www.photomacrography.net/forum/userpix/5919_Untitled12_1.jpg where: fc: condenser focal length alphaQ: condenser prism wedge angle fob: objective focal length alpha: objective prism wedge angle One aspect that I haven't seen discussed...

Re: shear angles and focal planes, we had a nice discussion about this over at photomacrography.net, see especially the posts by abednego: https://www.photomacrography.net/forum/viewtopic.php?t=38955&highlight= My own attempts to do Diy DIC with my set of Nikon Epi DIC prisms is slowly moving forwar...

No need to búy it, you can read the chapter here:

https://www.researchgate.net/publicatio ... microscopy

Yes, I'd be very surprised if a single darkfield stop performed OK with 4x, 10x and 40x objectives. Trying some of the phase inserts seems like a good idea. Glad you got the CT-5 telescope working, it'll help immensely for you to understand what's going on. Also, I haven't used Olympus objectives my...

Have you checked the back focal plane of your objective when set up for darkfield? Do you have a phase telescope? It sounds like you may be getting some light spill near the periphery of the rear aperture. No phase on microscope. What is the back focal plane of the objective? That sounds promisimg ...