Continuously variable darkfield / COL mask

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zzffnn
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Continuously variable darkfield / COL mask

Post by zzffnn »

Does any microscopist here have for sale or know of (an eBay search term of) a continuously variable darkfield / COL mechanical mask?

I like my Leitz Heine zoom condenser very much, and like to have a cheaper mechanical mask that does a similar thing for a regular condenser.

Something like the rosette part of this condenser:
http://www.ebay.com/itm/WATSON-amp-SONS ... 7675.l2557

I know it exists, but is rare.

I know of Zeiss pancratic condenser and Reichert Polyphos condenser but do not want those. I just want a universal mechanical rosette to put onto the focal plane of a regular condenser.

Thank you very much.
Selling my Canon FD 200mm F/2.8 lens

GaryB
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Joined: Fri Jul 29, 2016 12:18 pm

Post by GaryB »

I did a search on those a while back after seeing these on Molecular Expressions site https://micro.magnet.fsu.edu/primer/tec ... field.html to no avail. It may be possible to make a version of it using a small blacked cocktail umbrella as a pattern. Mounted on a spider, it could provide what's needed.

If I had a cocktail umbrella I'd try myself. It'd work if small enough. Hmm, where do I find one around here.... *rubs chin*

Cactusdave
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Joined: Tue Jun 09, 2009 12:40 pm
Location: Bromley, Kent, UK

Post by Cactusdave »

Usually called a leaf stop or variable leaf stop. They are quite rare but do occasionally turn up on Ebay. More useful information here http://www.olympus-lifescience.com/de/m ... darkfield/ Leaf stops are mentioned about half way down this informative page.
Leitz Ortholux 1, Zeiss standard, Nikon Diaphot inverted, Canon photographic gear

Ichthyophthirius
Posts: 1152
Joined: Thu Mar 07, 2013 5:24 am

Post by Ichthyophthirius »

Hi,

I've got one of these. From what I can see (I haven't dismantled it), they are not that complicated.

I'm waiting for someone to come up with a DIY version. You can build regular apertures with parts made by 3D printing or water jet cutting; shouldn't it be possible to build a reverse iris?

Someone needs to do the drawings :wink:

zzffnn
Posts: 1896
Joined: Thu May 22, 2014 1:25 pm
Location: Houston, Texas, USA
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Post by zzffnn »

Gary and Dave,

Yes, that was where I saw such a variable leaf mask initially.

Ichty,

I would be interested in such a 3D printing/DIY of reverse iris, if someone makes it. Use it with an aplanatic achromat condenser, results should be pretty good, even though there is no internal reflection mechanism (like that of Leitz Heine) to provide good light efficiency.
Selling my Canon FD 200mm F/2.8 lens

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