can I use a UV objective for darkfield?

[mes0]

Hi, I'm wondering if I can use a UV lens for darkfield? The one I am looking at is 100x with an iris..

any help greatly appreciated.

Thanks.

[Oliver]

Hello,
High NA objectives often do not work well for darkfield, but maybe the iris can compensate this (link: http://www.olympus-ims.com/en/microscopes/faq/#15).

UV objectives are made of a material which allows UV light to go through (sample illuminated with UV from top, with the UV light passed through the objective itself from the top). These objectives also show little auto-fluorescence. These objectives also allow visible light (=the emitted fluorescent light) to go through, of course. Darkfield (DF) operates with visible light. In DP the main microscope light is blocked out with a patch stop, and the sample is illuminated from the side. This has nothing to do with UV light and therefore I see (from a transmission standpoint) no problem.

Here is more info: https://www.microscopyu.com/articles/op ... ecial.html

Regards, Oliver

[gekko]

If I may add my 2 cents' worth to what Oliver has said: with a 100x objective, even with the iris closed, you may still have to use a special darkfield condenser rather than a simple darkfield stop with a regular condenser (for example if the iris does not allow the objective's NA to be reduced sufficiently, say to about 0.5). In any case, you may need to oil the condenser to the bottom of the slide (but never oil a condenser with nominal NA of less than 1.0 to avoid damage).

[mes0]

Thanks guys. I appreciate the elaboration.

I have a couple oil darkfield condensers shipping my way, each with two funnel stops..maybe I should just hold off on picking up an iris lens until after i try the stops?

[gekko]

I think that the funnel stops were meant to be used with specific objectives (of the same vintage and brand as the funnel stops/DF condenser) and will not work generally. I hope Oliver or apochronaut or another member will correct me or give more details. What microscope/objectives do you have and what DF condenser are you getting?

[mes0]

http://www.ebay.ca/itm/221852105592?_tr ... EBIDX%3AIT

Here's the condenser.

I currently have an old Olympus KHC with crappy old non plan lenses (http://indoorledgrowing.com/microscopes/ for pictures of the lenses + scope)

I've ordered a new LED light source that I am going to try n hack into it (since it is only a 20w light), and I will try and hack one of these condensers onto it..
100x darkfield is a long shot with this scope, but I'm playing around and learning and having fun with it, so we'll see what happens..

What I actually want is an infinity system (looking at AO/reichert/leica), but waiting for the right one to show up could take awhile and I'm impatient and hoping my hack job on this olympus will satisfy me temporarily for very little investment...(got the scope for 20$ cdn, and condensers worked out to 75$ cdn each shipped)..

[gekko]

I think you've got a nice, very well-made microscope, with very good optics. Plan optics in my view (for what it is worth) are very desirable for photomicrography of thin sections, but for live critters that are three dimensional or for visual observation of anything, they are unnecessary. But why do you want infinity-corrected optics? As far as I know, they have no optical advantage over 160-mm tube length except that they allow you to insert thick filters and the like between the tube lens and the eyepiece (and most such scopes do not appear to have a slot to allow you to do that anyway)? I hope that you'll get other, more expert opinions, though.
By the way, I once got exactly the same AO darkfield condenser at the flea market, but I've never tried to use it so far. Maybe I should. I also bought a B&L old DF condenser that looks like it's never been used (and I've not tried that one either ).

[mes0]

That olympus is a tank! It's close to 15lbs of steel. I was quite amazed someone would actually sell something that heavy for 20 bucks....probably the scrap steel alone is worth more.

With infinity I can insert a teaching head, polarizing units, camera attachments etc...with a 160 I don't think that is an option..

I was under the impression that the optics were improved as things switched to infinity...but hey I'm in beginners corner for a reason
Perhaps the improvements are only slight...probably really depends on what brands and vintages more than just 160vsINF.

I definitely want to do photography with this and especially videography.
I have a very nice DSLR that I am eager to try out...

You definitely should give your condensers a try!! Thats why you bought them isn't it?
I asked Apocronaut about these particular condensers prior to purchase and indicated that he had enjoyed using similar condensers.

[gekko]

I think you got yourself a great deal for $20. Those should last forever.

You definitely should give your condensers a try!! Thats why you bought them isn't it?
I asked Apocronaut about these particular condensers prior to purchase and indicated that he had enjoyed using similar condensers.

Thank you: I might try one of them. I shall need to adapt it somehow to fit my microscope. I just looked at the AO one, and it requires a slide thickness of 1.15 to 1.25 mm, and, fortunately, the slides I normally use are (nominal) 1.2 mm, so I'm all set except for adapting it to the substage then I can try them (maybe) with my 40x fluor oil immersion which has an iris to change aperture (NA 0.8-1.3) or maybe I'm building castles in the air...

[einman]

I have stands that use 160 TL and those that are infinity. I have never found myself unable to use cameras etc on the infinity stands i could not find similar for the 160 TL stands. For pure research stands where you are adapting multiple accessories to a single stand infinity might be better. However, I tend to favor my 160 TL stands because of the greater choice in low cost objectives on E-bay.

For example I just snagged a Nikon Fluor 40X/1.30 oil with collar. Looks to be in excellent condition. The newer Nikon infinity CFI objective sells for $780 to several thousand dollars. I paid less than $200.

[gekko]

I just snagged a Nikon Fluor 40X/1.30 oil with collar.

That is exactly the one I have and that I mentioned above .

[einman]

Excellent Gekko! I am putting together a stand for oil immersion, not necessarily darkfield, but could be. All 160 TL objectives; A mix of Zeiss, Nikon and Leitz objectives.

[einman]

http://www.ebay.ca/itm/221852105592?_tr ... EBIDX%3AIT

Here's the condenser.

I currently have an old Olympus KHC with crappy old non plan lenses (http://indoorledgrowing.com/microscopes/ for pictures of the lenses + scope)

I've ordered a new LED light source that I am going to try n hack into it (since it is only a 20w light), and I will try and hack one of these condensers onto it..
100x darkfield is a long shot with this scope, but I'm playing around and learning and having fun with it, so we'll see what happens..

What I actually want is an infinity system (looking at AO/reichert/leica), but waiting for the right one to show up could take awhile and I'm impatient and hoping my hack job on this olympus will satisfy me temporarily for very little investment...(got the scope for 20$ cdn, and condensers worked out to 75$ cdn each shipped)..

I have an American Optical 20 series for sale on E-bay. Great scope. Might be more than you want to pay though.

[mes0]

I may have it watched. Have been watching 20's 120's and 420's looking for something that will work.

what is the link to your listing or is it listed for 395?