Affordable finite low magnification oil iris objective list

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zzffnn
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Affordable finite low magnification oil iris objective list

Post by zzffnn »

Dear all,

I am buying a ~$200 USD finite ~40x oil iris objective for darkfield and COL, please kindly let me know your recommendations.

I would require it:

1) be equipped iris diaphragm , with NA ranging from about 0.6 to about 0.8 (wider range is fine, though 0.6-0.8 is required);
2) be of "oel" or oil type immersion (not water / dry objective);
3) have parfocal height of 33mm or 45mm (37mm old Leitz plus Leitz Plezy lens adapter will work too; but 34mm parfocal old Nikon would not work, 36mm parfocal Olympus would not be ideal);
4) provides around 40x at 160mm tube length

I already have: two 33mm parfocal oil immersion objectives at 25x NA 0.6 (adapted LOMO 190TL achromat) and 60x NA 0.7-1.0 (LOMO apo) and one 45mm parfocal objectives at 100x NA 1.32 iris (Zeiss Jena NF apo).

From Ichthyophthirius' list at http://www.photomacrography.net/forum/v ... nification
I gethered this list:

quote
Best buy:
Zeiss Planapo 40/1.0 Oil Iris (breathtaking contrast; good working distance; iris for darkfield use)

Inexpensive alternatives:
Leitz NPL Fluotar 40/0.70
Zeiss Achromat 40/0.85 Oil (very good for visual; long working distance; not so great for photos)
Zeiss Neofluar 40/0.75

Affordable alternatives:
Leitz NPL Fluotar 50/1.00 (very high contrast, good for photos; excellent all-rounder)
Leitz Achromat 50/1.00 W water immersion (very good for visual; long working distance; not so great for photos)
Leitz PL Apo 40/0.75
Zeiss Apo 40/1.0 Oil Iris
unquote

Would you please help me remove the dry objectives and add you recommnedations, if you are certain that they are oil immersion type?

The Zeiss Planapo 40/1.0 Oil Iris is slightly too expensive for my casual use, though I will consider it, if it is right at $200 USD shipped.

Another one I would consider is Nikon (45mm) plan achromat 50x 0.85.

I know at oil immersion NA around 0.6-0.8, tube length difference of 10mm is not detrimental. So an 170mm Leitz oil objective will work, as long as it comes with Leitz Plezy adapter. I understand eyepiece compensation may be different, but can tolerate that in this case.

Anything else I should look into? Thank you very much!

I understand have 33mm and 45mm objectives together in the same 5-hole nosepiece is not convenient, though it will work in my hands. I will simple shim a 45mm parfocal dry 10x to be pilot lens for my 45mm parfocal 100x. My 33mm parfocal 25x oil objective has long working distance to be pilot lens for my LOMO 60x iris objective.

Macro_Cosmos
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Re: Affordable finite low magnification oil iris objective list

Post by Macro_Cosmos »

Nu Life Sciences A 50x NA1.00 oil immersion, 160mm. Seen them for $80.
Not ideal, ~36mm parfocal, but really good image quality.
Could just make a parfocalising adaptor, to 45mm.

DPlan 50x NA 0.9 oil iris.
(More or less same as above, cheap too)

zzffnn
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Re: Affordable finite low magnification oil iris objective list

Post by zzffnn »

Thank you very much, Macro_Cosmos.

Your suggestion sounds attractive, though that 36mm parfocal height may cause me some headaches on the same nosepiece with 45mm and 33mm heights:

I don't have a Leitz Plezy yet (though I wouldn't mind buying one, to shim to 45mm). And to shim an extra 1mm, I don't remember whether or not I can do it with tiny rubber bands. 1mm will need lots of dedicated shim rings. Rubber bands are convenient, tunable and thick, but I don't remember it 1mm would be too much.

Is that Nu life Sciences 50x NA 1.0 iris an achromat? It doesn't say apo or fl(uorite) on it. There is an "A" on its shell, which I don't know what it means.

The Zeiss 40x NA 1.0 iris apo is what I am also considering now, though I haven't found one listed for under 200 USD.

Compared to the Zeiss apo, I am guessing the Nu Life 50x + Leiz Plezy + shim ring solution is neither convenient nor cost effective, but hey, it gets me another DIY opportunity to play with other short Leitz / Olympus options in the future!

zzffnn
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Re: Affordable finite low magnification oil iris objective list

Post by zzffnn »

I am also wondering for NA 1.0 COL, which condenser solution I should use:

1) a DIY patch stop centered perfectly at my turret condenser (with phase annulus replaced with a bigger DIY patch stop), even though the turret condenser does not have internal mirror surface typical of dedicated darkfield condensers;

or

2) a dry 0.7-0.9 dakrfield condenser (but I think its stop size at NA 0.7 is too small for nice contrasty NA 1.0 COL, even though it has internal mirror surface for better light efficiency).

I am leaning towards 1) here. Size matters when it comes to stop size.

I am fortunate have a very powerful 30W LED, so light is enough for anything (even for 100x objective NA 1.1 darkfield using a Leitz Heine).
Selling my Canon FD 200mm F/2.8 lens

Pau
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Re: Affordable finite low magnification oil iris objective list

Post by Pau »

This is not what you're asking (no iris) but the Leitz NPL Fluotar 50x/1.00 oel 160/0.17 I own is really excellent, in fact it seems apo or at least better colour corrected than any of the other NPL fluotars and PL fluotars I have. It is very good for dark field with the 1.2-1.4 oil DF condenser
With a bit of patience it could be found within your budget.
Pau

zzffnn
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Re: Affordable finite low magnification oil iris objective list

Post by zzffnn »

Thank you, Pau.

That Leitz is a great objective and many microscopists have recommended that to me.

For this inquiry / purchase though, I do require an oil iris objective. But I will definitely keep that NPL Fluotar 50x/1.00 in mind for the future.

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