2X and 1x 195 Achromatic Objectives

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Saul
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2X and 1x 195 Achromatic Objectives

Post by Saul »

Anybody tried these objectives (ebay item#)
323010412678
323010411656
Are they good enough for the simple observation ?
Saul

zzffnn
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Post by zzffnn »

Saul,

Those are infinity objectives. I assume you want infinity version, not 160 mm tube length version?

Also they said working distance is 50-60mm. The objective itself may be 33-45mm. So parfocal height is 83- 105mm. You want to have a free vertical space of 105mm, from objective shoulder to subject plane in focus + enough space for subject thickness.

Most regular compound microscopes do NOT have space for parfocal height of 105mm. Most offer less than 80mm, if I remember correctly.

But I am guessing what you have is not a regular compound microscope. So as long as your space is tall enough, then they should work. Their optical quality and correction may not be that good though.
Selling my Canon FD 200mm F/2.8 lens

Saul
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Post by Saul »

Thanks Fan,

I suspect that seller made a mistake in his description, from the photo they look like finite. There are infinite versions of these objectives, like 323010413761.
Image
I would like to use them (finite) on the simple compound Amscope B490B type microscope for my grandson
Saul

zzffnn
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Post by zzffnn »

Saul,

Don't buy those objectives, unless you know for sure that AmScope would offer 105mm parfocal height. Most likely, the finite 160 tube versions won't focus on that AmScope.

They may work on a Nikon Optiphot, when you lower the stage height all the way to very minimal or use condenser mount. But Optiphot is a pretty tall scope with adjustable stage height. That AmScope does not look tall enough.

I suggest a simple dissecting microscope for your grandson. The cheapest one on eBay costs about $35. I still use one like that in the field, as it is very light and decent enough for up to 20-30x total visual magnification.

If you have to get a compound objective, this objective (which I have) will work on that AmScope for sure:
https://www.ebay.com/itm/AmScope-A2X-2X ... 0814100004

1x objective with short working distance is actually expensive and not easy to find cheaply. Most 1x objectives have a working distance that is way tooooo long to work on stage of compound microscope (usual range is around 160mm). Nikon 1.2 Plan 0.03 with iris is likely the cheapest candidate: https://m.ebay.com/itm/Nikon-1-2x-0-03- ... 2969940850

I bought mine for about $100, though I have seen it sold at around $70.

You can always use high eyepoint wide field 5x eyepieces with 2x objective to get 10x total visual magnification.
Selling my Canon FD 200mm F/2.8 lens

rjlittlefield
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Post by rjlittlefield »

I have an Amscope T490 -- same base as the B490.

It definitely does NOT support 105mm parfocal distance. It is nominal 45mm parfocal, and the total focus block travel is not quite 30 mm.

--Rik

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