Heine Condenser vs an Oil Darkfield Condenser for Darkfield.

Here you can discuss different microscopic techniques and illumination methods, such as Brightfield, Darkfield, Phase Contrast, DIC, Oblique illumination, etc.
Post Reply
Message
Author
MicroMan2
Posts: 158
Joined: Tue Oct 14, 2014 4:20 pm
Location: Canada,Alberta

Heine Condenser vs an Oil Darkfield Condenser for Darkfield.

#1 Post by MicroMan2 » Tue Jun 28, 2022 1:03 am

Hello, right now I am fretting over a decision to potentially buy a Heine Condenser for Darkfield illumination. However, while the Heine is versatile in being able to transition between Phase, COL and Darkfield through a myriad of objectives; I am wondering if the excess cost justifies the Heine over dedicated condensers that are specific to different techniques Eg. A Darkfield condenser for darkfield. A phase set specific for PC, etc. My microscope is a n Olympus BHS with DIC but I would like to complement it with other techniques and I am curious to see everyone's input on the Heine regarding its pros and cons. Thank you for reading this forum post.

User avatar
blekenbleu
Posts: 299
Joined: Tue Feb 25, 2020 5:55 pm
Location: South Carolina low country
Contact:

Re: Heine Condenser vs an Oil Darkfield Condenser for Darkfield.

#2 Post by blekenbleu » Tue Jun 28, 2022 1:32 am

I suppose that a phase condenser can be used for darkfield;
at least, that is what I intend to try.
Metaphot, Optiphot 1, 66; AO 10, 120, EPIStar, Cycloptic

apochronaut
Posts: 6268
Joined: Fri May 15, 2015 12:15 am

Re: Heine Condenser vs an Oil Darkfield Condenser for Darkfield.

#3 Post by apochronaut » Tue Jun 28, 2022 2:25 am

The purpose of sn oil immersion DF condenser is to maximize the N.A. of a high resolution objective. Since the objective N.A. must be about .2 N.A. lower than the minimum N.A. of the condenser ; the higher the condenser N.A. , the higher the usable N.A. of the objective and thus the higher the resolution.
Heine condensers have a reasonably high N.A., so can perform very well for high resolution D.F. but there are condensers with a higher N.A. , so theoretically they should be able to provide slightly higher resolution. It isn't really a question of whether a Heine condenser is better than an oil DF condenser but which oil DF condenser because thqere are many permutations.
Normally too, most DF oil condensers are limited in their ability to be used with objectives below 40X because they have a limited illumination circle. Heine condensers can fill a wider field, so are useful over a broader range of magnifications than say a paraboloid or cardioid. . There are other condenser types such as Toric condensers that can do this too. Toric condensers are good from a 10X to 100X or higher objective.
Always though, there must be a way of limiting the N.A. of a high resolution DF objective : either an iris or funnel/diapragm stop.

Phase condensers are only useful for dry DF with objectives of 40X or below, sometimes only 20X.

MicroMan2
Posts: 158
Joined: Tue Oct 14, 2014 4:20 pm
Location: Canada,Alberta

Re: Heine Condenser vs an Oil Darkfield Condenser for Darkfield.

#4 Post by MicroMan2 » Tue Jun 28, 2022 3:24 am

Thanks for the reply, apochronaut. I also have some further questions on the Heine. Are there scenarios where the Heine or a variable DF condenser is more effective in imaging than DIC for maximizing contrast and resolution.

PeteM
Posts: 2982
Joined: Tue Dec 06, 2016 6:22 am
Location: N. California

Re: Heine Condenser vs an Oil Darkfield Condenser for Darkfield.

#5 Post by PeteM » Tue Jun 28, 2022 3:52 am

Your BHS DIC condenser should have phase rings included along with the prisms. With those, you should be able to get darkfield and oblique effects up to about 200-400x as "blekenbleu" and "apochronaut" suggest.

That would leave high magnification / oil immersion darkfield. I'd think a dedicated Olympus darkfield condenser, while not cheap, would be a bit cheaper than a Heine (about half of which seem to be missing the oil immersion cap) and likely to perform a bit better as well.

FWIW, I've just picked up a Heine condenser and adapted it to fit Nikon and Olympus scopes. Initial impression? It's pretty cool, but doesn't support the lowest magnification phase objectives. In addition, the Heine condenser from end to end is tall enough (66mm or so) to be a struggle to fit between the bottom of the stage and the condenser carrier at its lowest position for some scopes other than the intended Leitz.
.
.
HeineCondenser.png
HeineCondenser.png (325.11 KiB) Viewed 1983 times

User avatar
zzffnn
Posts: 3200
Joined: Sat Jun 20, 2015 3:57 am
Location: Houston, Texas, USA
Contact:

Re: Heine Condenser vs an Oil Darkfield Condenser for Darkfield.

#6 Post by zzffnn » Tue Jun 28, 2022 5:07 am

Microman2,

Heine will keep its resale value (it is a collector’s item); so you shouldn’t lose money if you don’t like it.

I sold my Heine after I got my PZO DIC set. I have also used a few dedicate oil darkfield condensers for high magnification darkfield and played with lots of COL / oblique techniques.

Heine has a very narrow illumination cone. The advantage is that it can provide slightly higher objective NA in darkfield, if your slide is perfectly clean and thin (note this is difficult to achieve with live water mount; mostly only expertly mounted diatoms slides are that perfect). Also Heine provides very quick transitions between illuminations, which is nice.

The disadvantage is that Heine’s narrow illumination cone produces quite some halos (donut bokeh) in phase contrast and COL. My eyes hate that busy background effect and much prefer background to melt away (as in DIC). Also Heine needs a lot of light, because it pass through such a narrow light cone.

Personally, I don’t think darkfield condenser needs to be variable. Yes, darkfield can be visually more pleasing than DIC for some subjects; though all dedicated oil darkfield condensers can do that (variable DF is mostly unnecessary).

So personally, for my situation, I don’t think Heine is worth to keep; but I don’t use phase contrast that much (and Heine is very versatile and useful for phase). So your situation may be different.

My compromise (poor man’s Heine) is a modified phase turret condenser with DIY darkfield masks of 3 different sizes and 2 high NA phase annuli. I am able to obtain decent immersion (NA around 0.7-0.8) darkfield that way, along with 40x and 100x phase with a quick turn of the condenser turret, though a dedicated oil darkfield condenser still produces better DF. My poor man’s Heine also provides adjustable oblique, using those DIY masks. I like this option, because it complements DIC and costs no more than $85 USD from me. When I need the best darkfield imaging, I would swap in a dedicated oil darkfield condenser.

MicroMan2
Posts: 158
Joined: Tue Oct 14, 2014 4:20 pm
Location: Canada,Alberta

Re: Heine Condenser vs an Oil Darkfield Condenser for Darkfield.

#7 Post by MicroMan2 » Tue Jun 28, 2022 11:27 am

Thank you for all the replies. One final note is that are oil darkfield immersion condensers able to provide DF from
0.40 to .70NA?

apochronaut
Posts: 6268
Joined: Fri May 15, 2015 12:15 am

Re: Heine Condenser vs an Oil Darkfield Condenser for Darkfield.

#8 Post by apochronaut » Tue Jun 28, 2022 11:34 am

Everything boils down to a budget and your universal type system makes a lot of sense. It is difficult to overcome condenser limitations without extending the system at some cost..
In the Heine, they tried to address those limitations but not perfectly successfully. Having the dual N.A. ranges helps in order to lower the N.A. and increase coverage.

I have the facility of being able to use a broad range of phase as well as DF and several interference types and if I had to limit myself to one of those contrast enhancement techniques I would probably choose the Toric DF condenser. It supports a broad range of objectives from 10X up to and beyond 100X, with excellent resolution at the high end, nudging an N.A. of 1.0., so equivalent to phase All you need is the condenser, BF objectives which most already have and in order to maximize the condenser's capability : some way of controlling the N.A. of any objectives over 1.0 AND you need a bright light source. It is hard to get around that.

There is another contrast enhancement system that doesn't get much notice. The variable slit condenser. PZO used one in their Polarizing Interference kit and Goerz offered one in the 60's/70's as a stand slone kit. The PZO uses a variable shape and oblique shift slit and the Goerz uses an oblique shift variable width slit. The Goerz also has a dry and oil ( 1.2 ) DF cap.
Both are quite effective in enhancing contrast and giving a 3 D. image. If one looks around : somewhere in the 150.00 range should land one. Sleeve mounts, easily adaptable to dovetails with a little design work.

apochronaut
Posts: 6268
Joined: Fri May 15, 2015 12:15 am

Re: Heine Condenser vs an Oil Darkfield Condenser for Darkfield.

#9 Post by apochronaut » Tue Jun 28, 2022 11:48 am

MicroMan2 wrote:
Tue Jun 28, 2022 11:27 am
Thank you for all the replies. One final note is that are oil darkfield immersion condensers able to provide DF from
0.40 to .70NA?
The N.A. doesn't matter with oil DF condensers. They work with any N.A. about .2 below their minimum N.A. However, the f.o.v. does matter. Oil DF condensers have a narrow f.o.v or illumination circle. and their usefulness is determined by the field coverage required. With a 20 mm f.n. 10X eyepiece, all will work down to a 40X objective, some to a 25X. Few to 20X.
The Toric is an exception, covering down to 10X.

Post Reply