Newbie Requests Help Identifying Some Microscope Objectives

[Ray Jade]

I’ve been reading and learning from this forum for the last few months and very much appreciate the open, sharing and patient dialogue.

I’ve a general interest to develop some skills in macro photography and perhaps microscopy and am slowly adding adapters and other kit.

Some years ago I was given a couple of surplus microscopes, a bag of bits and a couple of extra objectives. I can’t find much info on any of it and so would appreciate any insight or pointers anyone can offer:

Vickers binocular metallurgical microscope, Instrument Number M121924 (don’t know if this is model or serial number).

Objectives (all Vickers):
5 / 0.15 N9393
10 / 0.25 H1322
100 / 1.3 C7438 oil
40 / 0.64 K973 met

I’m assuming the format is ‘magnification / acceptance angle' but I don’t know what the codes mean. ‘Oil’ presumably is design of oil immersion but what ‘met’ is I don’t know?

Will Wetzlar binocular transmitted light microscope. No model or serial number identified. Course focusing does not work – I’ve had it apart and it seems a polyamide worm-gear that controls the stage is split. Reparable?

Objectives:
Will Wetzlar 160/- 4/0.10
Will Wetzlar 160/- 10/0.25
Will Wetzlar 160/0.17 40/0.65
‘BN’ 643360 40 0.75 (the ‘BN’ is Cyrillic with the ‘N’ reversed compared to the Latin alphabet.)

Nikon 21500 M10 0.25
Nikon 71471 M40 Plan 0.65

I’m assuming the best of the bunch are the Nikons and that they are nothing special.

Any information welcome; would any of the work reasonably mounted on a DSLR?

Thanks.

[zzffnn]

Welcome to the forum, Ray.

Those objectives that are 10x or less powerful can be used on DSLR, with plain extension tubes of around 150mm. Though your image cone may or may not cover your DSLR sensor well and you may get chromatic aberration. At 40x and above, they can be difficult to use on DSLR.

The objective label format you have there (40 / 0.64 K973 met) is magnification / numeric aperture catalog number(?not sure) and application (met means metallurgical = use without cover slip).

Numerical Aperture is defined as the Sine of half of the angle of light acceptance cone. Larger NA value produces the same effects as wider lens aperture.

Oil means oil immersion.

160 means 160mm tube length optical correction.

That gear is reparable, if you can find/make a replacement.

That "BN" objective is likely a LOMO water immersion objective that can be use with or without cover slip. Roughly in Cyrillic, that "B" means water, reversed "N" means immersion. LOMO marks their oil immersion as "MN".

[ChrisR]

metallurgical microscope

Does it have "epi" (top, through-objective) lighting - it would stick out sideways from above the turret. It might be missing.

[Ray Jade]

metallurgical microscope

Does it have "epi" (top, through-objective) lighting - it would stick out sideways from above the turret. It might be missing.

It does. There's an aperture with iris on the head with the objectives and a lamp assembly also with an iris. Lamp has a mains voltage transformer. Judging from the wiring, it's pretty old maybe 1960's.

All seems functional if grimy. The irises move but there's some rusting.

[Ray Jade]

Welcome to the forum, Ray.

Those objectives that are 10x or less powerful can be used on DSLR, with plain extension tubes of around 150mm. Though your image cone may or may not cover your DSLR sensor well and you may get chromatic aberration. At 40x and above, they can be difficult to use on DSLR.

The objective label format you have there (40 / 0.64 K973 met) is magnification / numeric aperture catalog number(?not sure) and application (met means metallurgical = use without cover slip).

Numerical Aperture is defined as the Sine of half of the angle of light acceptance cone. Larger NA value produces the same effects as wider lens aperture.

Oil means oil immersion.

160 means 160mm tube length optical correction.

That gear is reparable, if you can find/make a replacement.

That "BN" objective is likely a LOMO water immersion objective that can be use with or without cover slip. Roughly in Cyrillic, that "B" means water, reversed "N" means immersion. LOMO marks their oil immersion as "MN".

Thanks for the info especially on the LOMO.

I'll have a go with the 5x and see. I'm guessing that optical quality has improved in recent years an even low cost objectives may out perform them.

I'd deals like to get that gear replaced and make the microscope functional again. Lots of tiny things charging around in my pond, and boxes of old microfossils to go though.


Thanks for your help