Zeiss Achromat 40x/0.85 oil

75RR · Post by **75RR** » Tue May 24, 2016 3:36 pm

Has anyone used a Zeiss Achromat 40x/0.85 oil and have they found it a useful objective to have?

The Zeiss Optical Systems brochure mentions two 40/0.85 oil achromats, one with a recommended cover slip of 0.17mm and the other 1.5mm.
How does one distinguish between them?
All the Zeiss Achromat 40x/0.85 oil I have seen are marked 160/ - , would this be the 0.17mm one or the 1.5mm?

Perl · Post by **Perl** » Tue May 24, 2016 11:38 pm

Hi
Look like its miss matched text
this lens never existed
and if you look at lens you see
its not desigend for oil ( it shall be flat with end of metal then )

Regards
Pär

75RR · Post by **75RR** » Wed May 25, 2016 1:10 am

Hi Perl, thanks for heads up.

Had not noticed the lens. It does look recessed.

Had a look in the: Zeiss_prices_7-1-74 Catalogue and they have the same specs.

Perl · Post by **Perl** » Wed May 25, 2016 1:14 am

Hi

Yes its possible
Lens on picture anre not an oil lens

Best Regards
Pär

75RR · Post by **75RR** » Wed May 25, 2016 1:38 am

Had another look for images that showed the front lens.
First image is a closeup of the same objective - seller has added more images.
Second image is of the same type of objective.
First image would seem to be missing the top lens. That seem right?

Perl · Post by **Perl** » Wed May 25, 2016 1:58 am

Hi
More that the first pic showing an top lens
not in right position

Regards
Pär

Pau · Post by **Pau** » Wed May 25, 2016 4:44 am

Pelr, I can easily read Oel in the first picture, it's without doubt an oil immersion lens.

No idea about its usefulness, I'm not tempted to buy achromats, maybe would be nice as complementary objective to use with other immersion ones. For this NA I'm more tempted by dry corr objectives.
An excellent alternative is the Leitz NPL or PL Fluotar 50X 1.00 oel, a plan fluorite that in fact behaves like a Plan Apo.

The front lens effectively seems weird, don't buy it without a solid no asking full return policy.
I think that at NA 0.85 with oil immersion 0.02mm of cover glass thickness difference will not be relevant (for a dry lens will be)

zzffnn · Post by **zzffnn** » Wed May 25, 2016 6:13 am

Oel means oil immersion.

40/0.085 oel is useful for:

1) when there is too much water gap between cover slip and subject, as immersion objectives at that NA are much less sensitive than dry ones with that (oel or WI has much less spherical aberration).

3) when you lose your subject with your higher mag high NA oel objectives, this can be an intermediate scanner (after 4x or 10x objectives, which can look through a drop of oil)

If your seller is Curt or Paul Martin, then you should ask them directly about 0.17 vs 1.5 mm cover. They know their trade and catalog numbers, more so than hobbyists. They offer excellent return policy too. They will likely pay your return shipping, if they cause the return by their mistakes.

Absence of specific designation, "-" should mean 0.17 mm. 1.5 mm is probably too much to correct for NA 0.85, even for oel.

Angle of those two photos are different and cannot be compared. The first magnified image has some reflection that is difficult to avoid and could cause your confusion.

75RR · Post by **75RR** » Wed May 25, 2016 7:16 am

... maybe would be nice as complementary objective to use with other immersion ones.

Thanks Pau,
Yes the idea was/is to complement my existing oil objectives.
Have a 63x and a 100x so a 40x when combined with my Optovar at 1.25x looks to give a nice range.
40x - 50x* - 63x - 78x* - 100x - 125x*
* multiplied by Optovar

The first magnified image has some reflection that is difficult to avoid and could cause your confusion.

Thanks zzffnn,
A better photo would definitely help. Awaiting seller's reply.

Ichthyophthirius · Post by **Ichthyophthirius** » Wed May 25, 2016 2:10 pm

Hi,

Pär is right. The front glass plate of the objective in the picture is missing. It's broken and in this condition, it can't be used for oil immersion.

There are two versions of this objective:

461706: for use without coverglass or with a thin cover glass 0.17 mm (marked "-") and working distance 0.35 mm

461708: for use through a slide or culture vessel of about 1.5 mm thickness (marked "1.5") and working distance also 0.35 mm

I have the 461706; it's a great objective for observation and usually you can get it for a very low price. It's a big improvement on a 40:1 NA 0.65 dry objective for resolution and especially for thick mounts for reduced spherical aberration. Objects in thick balsam mounts are crystal-clear. Also a good scanning objective. Not so good for photography because it's not plan and it has visible colour fringes. http://www.mikroskopie-forum.de/index.p ... c=14817.60

Better for photography is the Zeiss Planapochromat 40/1,0-0,6 Oel Iris "46 17 46" which also has a good working distance of 0.22 mm (!). It's many microscopist's favourite objective but it's difficult to get one that is without delamination. I have one with light delamination and it's still great to work with.

Regards, Ichty

75RR · Post by **75RR** » Wed May 25, 2016 3:01 pm

Many thanks Ichty,
your review was just what I was looking for.

Pity about the lens on the objective but good to know.
Can't imagine why the seller has not mentioned it. He is supposed to have a good rep.

Super link! Great objective comparison. Google translate and I are wading through it. :)

Perl · Post by **Perl** » Wed May 25, 2016 11:39 pm

Hi
once again then

This lens are not going to work with oil

1: Look at top lens ( totaly wrong position )
2: Missing parts or wrong asseblied lens

Regards
Pär

Perl · Post by **Perl** » Wed May 25, 2016 11:41 pm

Pau:
Pelr, I can easily read Oel in the first picture, it's without doubt an oil immersion lens.

Hallo i think everybody here can that , but as i wrote
there are somthing wrong with the lens here

/ Pär

75RR · Post by **75RR** » Thu May 26, 2016 3:37 am

Thanks Pär,
I agree, you never said it wasn't an oil lens, just that it could not be used as one because it was broken.
An indifferent photo did not help the rest of us in this diagnosis. Well spotted.
Thanks again for your input.

Glen

Choronzon · Post by **Choronzon** » Thu May 26, 2016 5:42 am

Just an FYI for all about immersion lenses; DIN standards are black ring at the tip for oil immersion, white ring at the tip for water, and orange ring for glycerine OR multi immersion. Easy to identify this way, unless it's been aggressively cleaned by generations of lens wipers, and the ring has been wiped off.
Also this lens in question, was an entry level clinical lens to count blood without having to coverslip the slide. Very economical for labs back in the day.
And, yes, the front element has fallen out, so not much use for anything except a nosepiece dust plug.