DIC Microscope

[mike42]

I'm looking around for a DIC capable microscope mainly for viewing pond water critters. Understand there are two types: transmitted and reflective, but not sure if either is superior to the other in viewing protists. Anyone out there had experience in viewing protists with DIC microscope? There's a Canadian on eBay offering DIC in the $1000 - $2000 range. Sounds a little too good to be true.

[Scarodactyl]

That listing looks wack to me.
You need transmitted dic, not epi. Epi is for looking at reflective surfaces.

[dtsh]

If it's the same one, I had looked at it for the stand but I don't know enough about DIC to know if it's all there. It's eBay, so if you're not pressed for time you could get it and if it's not complete return it for a full refund (seller pays shipping if it's not as described (i.e. not a working DIC microscope)).

I completely understand the hessitation, having seen it myself and thought about it. There appears to be only one prism with it, which could be normal, but if different magnifications or other changes require different prisms you're likely out of luck as I have seen exceedingly few DIC setups in that brand.

[ScienceMatters]

That Canadian eBay seller has been posting microscopes with “PlasDic” (you can google it) and not making it very clear that it is not traditional DIC. It’s tough to find a transmitted light scope with a true DIC system for less than a few thousand or more, unfortunately.

[mike42]

Thanks for all the comments. Adequately answered a number of questions I had. Doesn't look like I'll be buying anytime soon.

[apochronaut]

Here is the Nomarski DIC Diastar. https://www.ebay.com/itm/CAS-Reichert-D ... ect=mobile

It is likely that the Microstar plas DIC is at least partially legit. Plas DIC uses a slit condenser below the stage and the prism and polarizer are above the specimen. Pretty simple . If the slider is remote from the objective one slider can be used with more than one objective. The system is basically identical to the slit condenser interference contrast that PZO included in their broad Interference Contrast kit. It had a Nomarski system as well, all designed by Max Pluta and made by PZO from the early 70's. One difference though, is that Pluta's system used a polarizer below the stage too, the same as that Microstar has. The Zeiss patent then is slightly different than Pluta's.
Anyway, the Microstar looks like a Reichert attempt to make a budget DIC system, since they already had a relatively nice Nomarski system.
They were probably using up old series 10/20 DIC nosepieces with the slider channel and at least 2 of the objectives are marked strain free. Older objectives too, so that all looks right, just from another era.
The one odd thing about it is that those 34mm parfocal objectives don't belong with that head. Viewing them through a series 400 head gives a terrible image, full of spherical aberration and all kinds of ca.

However, I have seen the 400 head used on later 150s and 1820s, which both used the 34mm objectives, so maybe they made a modified 400 series head for those applications. Perhaps a series 100 telan lens in it or other corrective modifications?

[PeteM]

In addition to the wrong objectives for the head (plus another that looks an even worse fit), the top slider with the stick-on PlasDic label doesn't look to be the proper A.O./Reichert one - at least in comparison to the one I have. If so we have none of the four DIC prisms that should be in the condenser and some unknown DIY prism/polarizer (??) above the objectives. What we might have is some sort of polarization and oblique?

Most of the extra cost of a DIC system is in the prisms. These typically range from $200 to $500 each, used, and around $1000 or more new. That scope seems to be missing five OEM prisms it should have. Curt's listing (the Diastar, linked above) does have all right components and is priced accordingly.

[apochronaut]

Plas DIC or the Pluta slit condenser Interference contrast system do not use condenser prisms. They use a slit condenser .

[PeteM]

Right. But it looks to be a DIY effort and is most certainly not a Reichert offering. It would help to know exactly what prism is being used in the top slider - anyone recognize it?

Even a properly configured PlasDic sytem is limited to about 400x - DIC's superior resolution really begins to shine with something like a 60x PlanApo.

http://microscopy.berkeley.edu/courses/ ... asdic.html

[wabutter]

I can assure you it was not an AO/Reichert/Leica offering. There were many third party modification to most major brands of microscope for what was essentially an oblique illumination slit condenser and slit at the back aperture of the objective. Commonly known as Hoffman Modulation. The patents ran out (forgive my old brain) I think in the 90’s. It could be wrong on this.
Hoffman would modify the big four objectives and condensers as an OEM type operation. As changes came to objective design it became harder to access the exit pupil to the objectives.
HM offered advantage over DIC when used with plastic specimen vessels , especially on inverted scopes. Hence I think that was the reference to PlasDIC.
Leica did dabble in HM concept later on with the DMIL inverted scope. I can’t remember if it made into the DM IRB, but it was not branded PlasDIC.

[apochronaut]

Might explain why the photos are black and white. The really odd thing is they used a series 10 nosepiece , crudely spraypainted to match the colour scheme of the Microstar! Where did they get the nosepieces with slider channels in them, just like the ones used on the series 10 DICV and the series 21? There were no DIC nosepieces for the 100 series of microscopes, and the DIC nosepieces made for the 400 series were 6 hole, interchangeable dovetailed. Could work on a 410 but in need elsewhere, which the 10 nosepieces with slider channels were not.
AO did not sell many DIC 10/20 microscopes. They would have had a lot of nosepieces with slider channels sitting in the warehouse.

[dtsh]

Might explain why the photos are black and white. The really odd thing is they used a series 10 nosepiece , crudely spraypainted to match the colour scheme of the Microstar! Where did they get the nosepieces with slider channels in them, just like the ones used on the series 10 DICV and the series 21? There were no DIC nosepieces for the 100 series of microscopes, and the DIC nosepieces made for the 400 series were 6 hole, interchangeable dovetailed. Could work on a 410 but in need elsewhere, which the 10 nosepieces with slider channels were not.
AO did not sell many DIC 10/20 microscopes. They would have had a lot of nosepieces with slider channels sitting in the warehouse.

Nice spotting the 10 series turret. It's hard to tell from the images, but one of them with a closeup of the nose looks to have some tooling marks where the slider goes, so perhaps they are machining series 10 parts due to availability. It speaks volumes to the attention to detail one might expect when they can't even bother getting good paint coverage.