Leitz Phaco 1 EF L32/0.40 160/- Objective

[ChrisR]

Leitz Wetzlar Phaco 1 EF L32/0.40 160/- 519437
Is this objective intended for looking down into water at bugs?

The WD is about 7mm.

There's no diaphragm. (I have another, non phase, which has one).

Then a query about Phase -
I have a Leitz HMP (with the Pol parts).
I also have a 402a phase condenser which fits the slot.

But the scope came with 170TL objectives
Apart from the small error due to TL, are these parts likely to be compatible?

Is "Phaco" just what Leitz calls "phase"?

There's a 170TL version too : https://www.ebay.com/itm/Leitz-Wetzlar- ... SweDdaovAN)

Edit - I found some answers but more questions.
Diavert manual http://www.micromagus.net/Microdocs/diavert_manual.pdf
says things about the Condenser 91, aperture 0.25 which I assume means the NA is then low enough not to show aberrations from the coverslip error.
I'm still not sure if a 402a would suit, when non-inverted.

(The same page also states what NPl means, which we were fussing over, years ago.)

[zzffnn]

ChrisR,

Leitz document says Phaco means "phase contrast Zernike" (not Pv variable phase of Heine). If you see a dark phase ring at objective back lens, then it is a phase objective.

In general, 7mm WD is quite long for NA 0.40. That is why Leitz called it "L": long working distance.

Usually, NA 0.4 objective will have a phase ring aperture of around NA 0.20 (phase ring in objective is usually half the native aperture, though there are exceptions). So in phase mode, such objective will view through 1mm or so water without any image degradation.

That "-" dash means with or without cover slip.

Edit:
I don't have specification for 160mm 32/0.40. But Leitz gave the same "code no." "519437" to their 170/-/45mm 32/0.40 Phaco 1 version. That objective has WD of 6.4mm and is an achromat.

[Ichthyophthirius]

Leitz Wetzlar Phaco 1 EF L32/0.40 160/- 519437
Is this objective intended for looking down into water at bugs?

It is usually intended to be used looking up. On an inverted microscope, through the base of a thicker vessel. This particular objective is designed for cover glass thicknesses 0.17-0.3 mm, WD is 6.55 mm. See the Labovert manual, page 12 http://www.frankshospitalworkshop.com/e ... manual.pdf

The NA of 0.4 is very low for a 32:1 objective, so there is little degradation of the image when looking through a slide or a layer of water. NA 0.4 is usually the highest NA on the little inverted microscopes that are used in tissue culture labs. Zeiss had a similar F-LD 32/0.40 160/1.2. The image quality is not great; much nicer to use a 20/0.40 with correction collar (Nikon, Olympus).

The EF 32/0.40 160/- should be fully compatible with your 170 mm microscope. The 2 mm difference in tube length doesn't matter for an objective 32:1. The size of the phase ring Phaco 1 should also be the same.

Condenser 91 (NA 0.25) sounds like a long working distance condenser for an inverted microscope. You should also be able to use the 402a condenser; however, I don't know if you have to/would be able to swing out the front lens for Phaco 1. Maybe you can swing out the front lens and use the Phaco 2 or Phaco 3 ring? Give it a try.

Regards, Ichty

[ChrisR]

Thanks Ichthy. That Labovert looks nice.
Makes sense.
I find I have Nikon 20x/0.4/0-2 Ph2, though the WD is much less.

No inverted scope likely to be coming though, so may let the Leitz go.

[zzffnn]

ChrisR,

Icthy is surely right about NA 0.40 being somewhat low for 32x. Maybe that is also why it offers LWD.

Does your 32/0.4 objective say "160/-" on its shell?

I would consider it contradictory, if that is the case, as Icthy's pdf clearly says 0.17-0.3mm for the same objective.

My Leitz catalog refers 170/- 32/0.4o version as "DO" = with or without cover too.

But I remember some manufacturer actually use "-" for "cover depth does not matter, within reasonable error range", instead of "usable with or without cover".

Is that the case here, Ichty? I am just curious. Thank you for sharing.

[Ichthyophthirius]

But I remember some manufacturer actually use "-" for "cover depth does not matter, within reasonable error range", instead of "usable with or without cover".

That's right, "cover glass thickness does not matter, taking into consideration magnification and NA"

Which for a 10/0.25 160/- means with or without cover glass and for a Planapo 63/1.40 160/- oil, a cover glass between 0.16 and 0.19 mm. So the "-" can mean different things.

Maybe here the "-" is a bit misleading; "0.17-0.3" would have been better but in real life, they are often used through 1.2 mm slides or 2 mm plastic. The image isn't great but it's enough to check a cell culture.

Regards, Ichty

[ChrisR]

Does your 32/0.4 objective say "160/-" on its shell?

Yes. It doesn't look exactly like the 170 versions - as though it's a different generation.